Although diffuse large B-cell lymphoma (DLBCL), the most common type of non-Hodgkin lymphoma, was once considered to be a single disease, novel insights into its biology have revealed that it is molecularly heterogeneous. Technologies such as gene expression profiling have revealed that DLBCL consists of at least three distinct molecular diseases that have disparate outcomes following standard therapy. These subtypes arise from different stages of B-cell differentiation and are characterized by distinct oncogenic activation mechanisms. This knowledge has led to the investigation of strategies and novel agents that have selective activity within molecular subtypes and sets the stage for an era of precision medicine in DLBCL therapeutics, where therapy can be ascribed based on molecular phenotype. This work offers the chance of improving the curability of DLBCL, particularly in the activated B-cell subtype, where standard approaches are inadequate for a high proportion of patients.

See all articles in this CCR Focus section, “Paradigm Shifts in Lymphoma.”

Clin Cancer Res; 20(20); 5182–93. ©2014 AACR.

Diffuse large B-cell lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma diagnosed in the United States each year. Although the addition of rituximab to cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) improved curability of the disease, there remain a significant proportion of patients for whom standard therapy is ineffective (1). Over recent years, the availability of gene expression profiling and other high-resolution genetic technology has provided novel molecular insights into DLBCL and revolutionized our understanding of its biology (2–5). We now appreciate that this disease constitutes several molecular subtypes, originating from different stage of B-cell differentiation (3, 6–10). Most cases arise either from a germinal center B cell (GCB) or an activated B cell (ABC) that is blocked during plasmacytic differentiation. When these two subgroups were first identified, GCB DLBCL constituted 45% to 50% of cases—some DLBCL tumors did not fit into either GCB or ABC definitions and were called “unclassifiable.” Later, another subtype called primary mediastinal B-cell lymphoma (PMBL) that makes up 10% of cases was also recognized. This new molecular taxonomy for DLBCL is important because distinct subtypes have disparate outcomes following standard therapy (11). This lays the foundation for testing new agents and novel strategies in distinct subtypes of DLBCL and investigating whether they have selective activity within these.

The applicability of gene expression profiling (GEP) and this new molecular taxonomy to clinical practice has been challenging, though, as GEP using microarrays on RNA derived from frozen tissue is not widely available and is expensive to perform. Therefore, many groups investigated the use of relatively inexpensive immunohistochemical methods and developed immunohistochemistry algorithms to predict cell of origin (12–14). While these techniques have been somewhat helpful, they have demonstrated varying degrees of concordance with microarray results, limiting their usefulness (15–18). Therefore, novel, more accurate assays to predict cell of origin are needed. Recently, quantitation of gene expression in formalin-fixed paraffin-embedded tissue (FFPET) was shown to be feasible in lymphoma cases, and the Lymphoma and Leukemia Molecular Profiling Project recently described a robust method for cell of origin assignment using a 20-gene assay (Lymph2Cx)—with this digital gene expression (NanoString)–based test, importantly, there was >95% concordance of cell of origin assignment between two laboratories (15, 19). The assignment of cell of origin by this assay also appeared more robust than by the widely used Hans algorithm (Fig. 1). This assay also has a rapid turnaround time of 36 hours, suggesting that it could be used for patient selection in prospective clinical studies and ultimately in the community for determination of upfront therapy, pending the results of ongoing studies.

Figure 1.

Patients with DLBCL outcomes following R-CHOP according to the cell of origin (COO; in the independent validation cohort). A, progression-free survival (PFS) for COO assignment using the “Hans” algorithm. B, overall survival (OS) for COO assignment using the “Hans” algorithm. C, PFS in the COO groups as determined by the Lymph2Cx assay. D, OS in the COO groups as determined by the Lymph2Cx assay. E, PFS in the COO groups determined by the gold-standard method applying the previously described model to gene expression on frozen tissue (FT). F, OS in the COO groups determined by the gold-standard method. The P values are from log-rank tests comparing the ABC and GCB groups. The log-rank tests are one sided in the direction of greater hazard for ABC. RR, relative risk (with the 95% confidence interval in brackets) associated with the ABC group compared with the GCB group. Republished with permission of the American Society of Hematology from ref. 19: Scott DW, Wright GW, Williams PM, Lih CJ, Walsh W, Jaffe ES, et al. Determining cell-of-origin subtypes of diffuse large B-cell lymphoma using gene expression in formalin-fixed paraffin-embedded tissue. Blood 2014;123:1214–7. Permission conveyed through Copyright Clearance Center, Inc.

Figure 1.

Patients with DLBCL outcomes following R-CHOP according to the cell of origin (COO; in the independent validation cohort). A, progression-free survival (PFS) for COO assignment using the “Hans” algorithm. B, overall survival (OS) for COO assignment using the “Hans” algorithm. C, PFS in the COO groups as determined by the Lymph2Cx assay. D, OS in the COO groups as determined by the Lymph2Cx assay. E, PFS in the COO groups determined by the gold-standard method applying the previously described model to gene expression on frozen tissue (FT). F, OS in the COO groups determined by the gold-standard method. The P values are from log-rank tests comparing the ABC and GCB groups. The log-rank tests are one sided in the direction of greater hazard for ABC. RR, relative risk (with the 95% confidence interval in brackets) associated with the ABC group compared with the GCB group. Republished with permission of the American Society of Hematology from ref. 19: Scott DW, Wright GW, Williams PM, Lih CJ, Walsh W, Jaffe ES, et al. Determining cell-of-origin subtypes of diffuse large B-cell lymphoma using gene expression in formalin-fixed paraffin-embedded tissue. Blood 2014;123:1214–7. Permission conveyed through Copyright Clearance Center, Inc.

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All three subtypes of DLBCL are characterized by distinct genetic aberrations, though there is some overlap observed (Fig. 2). For example, the GCB subtype, which is most commonly encountered, is associated with markers of the germinal center such as CD10 as well as the BCL6 gene (20). The key molecular feature of the ABC subtype is constitutive activation of the NF-κB pathway with high expression of NF-κB target genes. BCL2 is expressed by both the GCB and ABC subtypes—in the GCB subtype, its expression is typically associated with a t(14:18) translocation, whereas in the ABC subtype, its expression reflects NF-κB activation (6). These contrasting molecular features suggest distinct derivations of the GCB and ABC subtypes from different stages of B-cell differentiation. Importantly, following standard immunochemotherapy (R-CHOP), the outcome for patients with the ABC versus the GCB subtype appears to be inferior (11; Fig. 2).

Figure 2.

Oncogenic pathways for GCB, ABC, and PMBL DLBCLs. These subtypes originate from various stages of B-cell differentiation and acquire distinct oncogenic abnormalities as shown. AID, activation-induced cytidine deaminase; ITAM, immunoreceptor tyrosine-based activation motifs. Blue lines, activation; red lines, indicate inhibition. From ref. 102. New England Journal of Medicine. Lenz G, Staudt LM. Aggressive lymphomas. Vol. 362, pp. 1417–29. Copyright © 2010. Massachusetts Medical Society. Adapted with permission from Massachusetts Medical Society.

Figure 2.

Oncogenic pathways for GCB, ABC, and PMBL DLBCLs. These subtypes originate from various stages of B-cell differentiation and acquire distinct oncogenic abnormalities as shown. AID, activation-induced cytidine deaminase; ITAM, immunoreceptor tyrosine-based activation motifs. Blue lines, activation; red lines, indicate inhibition. From ref. 102. New England Journal of Medicine. Lenz G, Staudt LM. Aggressive lymphomas. Vol. 362, pp. 1417–29. Copyright © 2010. Massachusetts Medical Society. Adapted with permission from Massachusetts Medical Society.

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The third subtype of DLBCL is called primary PMBL and is typically diagnosed in young female patients. It is putatively derived from a thymic B cell and shares many clinical and molecular features with classical Hodgkin lymphoma of the nodular sclerosis type (21–23). GEP studies have shown that PMBL and classical Hodgkin lymphoma share a third of their genes, and in fact, very rarely, mediastinal lymphomas with histologic features intermediate between PMBL and classical Hodgkin lymphoma (mediastinal gray zone lymphoma) are diagnosed (24, 25). It is important to consider that unlike the other subtypes of DLBCL, PMBL has defective immunoglobulin production and does not express surface immunoglobulin. Therefore, strategies targeting B-cell receptor signaling are unlikely to be helpful in this subtype.

Most newly diagnosed patients with DLBCL receive rituximab in combination with a chemotherapy backbone consisting of CHOP. This backbone has been used since the early 1970s when doxorubicin was added to cyclophosphamide, vincristine, and prednisone (CVP), and CHOP became the first curative regimen in DLBCL, highlighting the critical role of anthracyclines. Later, in an attempt to improve upon the results with CHOP, subsequent studies focused on the empiric addition of drugs to the regimen. This did not improve survival, however, as evidenced in a pivotal randomized study comparing CHOP with second- and third-generation regimens, where there was no evidence of superiority (but higher toxicity) with the latter approaches (26). Later, other groups, such as The Deutsche Studiengruppe für Hochmaligne Non-Hodgkin'Lymphome (DSHNHL), also attempted to improve upon the outcomes with CHOP. They carried out four-arm studies of CHOP, where they tested different schedules of the regimen (every 14 vs. every 21 days) with or without etoposide (CHOEP) in both older (>60 years) and younger (≤60 years) patients (27, 28). Although CHOEP-21 benefited patients ≤60 years and CHOP-14 patients >60 years, these survival gains did not remain significant with the addition of rituximab [following a study from Groupe d'Etudes des Lymphomes de l'Adulte (GELA) that showed a survival advantage in older patients treated with R-CHOP versus CHOP; refs. 27–31]. The RICOVER-60 study was a randomized comparison in elderly patients of 6 versus 8 cycles of CHOP-14, with or without rituximab (30). Although the DSHNHL found no significant differences in survival between the two groups, they concluded that R-CHOP-14 should be adapted as the new standard based on historical comparisons in this population (30). Subsequently, however, two randomized studies—one in all age groups (≥18 years) and the other in older patients (>60 years)—showed no benefit of R-CHOP-14 over R-CHOP-21, and hence, the latter remains the standard (32, 33; Fig. 3).

Figure 3.

Evolution of DLBCL therapeutics. Schema of progress in DLBCL clinical trials over the past 30 years. This schema shows selected randomized studies in DLBCL from the pre- to post-rituximab eras and within molecular subtypes of DLBCL. m-BACOD, methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, dexamethasone; ACVBP, dose-intensified doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone; R-CHOP-I, R-CHOP ibrutinib; R2-CHOP, R-CHOP with lenalidomide (Revlimid); RB-CHOP, R-CHOP with bortezomib. *, in non-GCB DLBCL.

Figure 3.

Evolution of DLBCL therapeutics. Schema of progress in DLBCL clinical trials over the past 30 years. This schema shows selected randomized studies in DLBCL from the pre- to post-rituximab eras and within molecular subtypes of DLBCL. m-BACOD, methotrexate, bleomycin, doxorubicin, cyclophosphamide, vincristine, dexamethasone; ACVBP, dose-intensified doxorubicin, cyclophosphamide, vindesine, bleomycin, and prednisone; R-CHOP-I, R-CHOP ibrutinib; R2-CHOP, R-CHOP with lenalidomide (Revlimid); RB-CHOP, R-CHOP with bortezomib. *, in non-GCB DLBCL.

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Other researchers have investigated increased dose-intensity approaches as an alternative to R-CHOP. Rituximab with doxorubicin (Adriamycin), cyclophosphamide, vindesine, bleomycin, and prednisone (R-ACVBP) was compared with R-CHOP-21 in a randomized study performed by the GELA group, in patients under 60 years with an age-adjusted International Prognostic Index (IPI) score of 1 (34). Although the R-ACVBP arm demonstrated an improved progression-free survival (PFS; 87% vs. 73%), the significant hematologic toxicity of the regimen confines its use to younger patients, and it is not feasible for most (older) patients who have DLBCL. This restricts its potential to replace R-CHOP as the universal platform for this disease. Other intensive approaches, such as using autologous stem cell transplantation in the upfront setting, have been tried but they have never shown a clear benefit over R-CHOP alone and are associated with much higher toxicity (35). Another increased dose-intensity regimen is dose-adjusted etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin with rituximab (DA-EPOCH-R; ref. 36). Following promising activity in NCI and Cancer and Leukemia Group B (CALGB) single-arm studies, a randomized study (that incorporated molecular profiling) comparing DA-EPOCH-R with R-CHOP recently completed accrual, and results are awaited (37).

This is the most common subtype of DLBCL and represents almost all cases (excluding PMBL) that are diagnosed in children, adolescents, and young adults (38). Though it appears to have a much better outcome compared with ABC DLBCL following standard therapy, approximately 30% of patients with GCB DLBCL do not achieve cure with R-CHOP (11). The BCL6 gene is a transcriptional repressor and has been shown to be a critical regulator of the germinal center with important roles in the regulation of apoptosis, lymphocyte activation, and the DNA damage response (39). Although up to 40% of GCB DLBCL cases harbor a BCL6 chromosomal translocation, deregulated BCL6 may also result from mutations not involving the BCL6 locus (20). Translocations and somatic mutations of BCL6 can augment the inhibitory effect of BCL-2 on the apoptotic stress response, resulting in tumor proliferation and treatment failure. This suggests that BCL6 is an important therapeutic target in GCB DLBCL (40).

Specific small-molecule inhibitors of BCL-6 are currently in development (40–42). One such inhibitor—called 79–6 complex—works by binding to the BCL6 BTB domain corepressor binding groove (41). Strategies such as histone deacetylation inhibition—to overcome the repressive effects of BCL6 on p53 and cell-cycle–inhibitory proteins—are also potentially interesting in DLBCL (43, 44). One recent study demonstrated that treatment of DLBCL cell lines with pan-deacetylone inhibitors in combination with niacinamide produced synergistic toxicity in GCB over ABC subtypes and led to acetylation of BCL6 and p53 (44). In a phase I proof-of-principle study, 24% of patients with relapsed lymphoma attained a response to vorinostat and niacinamide.

Cells in the germinal center are rapidly dividing and topoisomerase II dependent, and therefore strategies that target topoisomerase II are rational in GCB DLBCL. Agents such as etoposide can inhibit topoisomerase II via ubiquitin-mediated protein degradation and possibly transcriptional inhibition resulting in downregulation of BCL6 (45). This is interesting when one considers the improvement in event-free survival in younger patients when etoposide is added to CHOP (CHOEP vs. CHOP alone). Younger compared with older patients have a much higher proportion of GCB DLBCL, and this may explain the benefit of adding etoposide in this group (27, 28). Though any survival benefit of adding etoposide did not persist with the addition of rituximab to CHOP (R-CHOEP), the earlier results suggest that GCB DLBCL may be sensitive to strategies that incorporate topoisomerase inhibition (29). The DA-EPOCH-R regimen includes the topoisomerase II inhibitors etoposide and doxorubicin, and topoisomerase II inhibition is optimized by the continuous infusion of agents in addition to pharmacodynamic dosing. This ensures adequate steady-state concentrations that may be critical in tumor cell kill (36). Following DA-EPOCH-R in patients with DLBCL, the outcome of the GCB subtype was particularly promising—at a median follow-up of 5 years, event-free survival (EFS) ranged from 95% to 100% (46, 47).

The histone methyltransferase enhancer of Zeste homolog 2 (EZH2) is another interesting therapeutic target in GCB DLBCL (48–50). In GCB DLBCL, gain-of-function mutations in the H3K27 methyltransferase EZH2 are present in 25% of GCB DLBCL. Inhibitors of EZH2 are toxic to GCB cell lines and are currently in development and may be helpful in this subtype (48, 49).

ABC DLBCL is rarely diagnosed in children and younger patients and proportionally increases in incidence with advancing age. Results from many studies suggest that it is the subtype with the worst outcome following standard therapy, so novel approaches are particularly needed for these patients (11, 51). These tumors have constitutive activation of the NF-κB pathway that drives tumor proliferation and survival and confers chemotherapy resistance. The NF-κB pathway is also important in marginal zone B-cell lymphomas, and Zucca and colleagues (52) discuss this in this CCR Focus edition. Early studies by Davis and colleagues (53) validated NF-κB as a therapeutic target in ABC DLBCL. In both GCB and ABC cell lines, an inhibitor of IκB kinase (which is critical for activation of NF-κB) was tested and showed differential activity within ABC cell lines. Subsequently, a clinical study was developed based on the hypothesis that inhibiting NF-κB in DLBCL might sensitize ABC (but not GCB) DLBCL to chemotherapy (54). The investigational agent in the clinical study was bortezomib, a proteasome inhibitor that prevents the degradation of phosphorylated IκBa in the proteasome, which leads to inhibition of NF-κB activity in ABC DLBCL cell lines in vitro. Bortezomib was tested in combination with anthracycline-based chemotherapy (DA-EPOCH) in relapsed and refractory DLBCL, and molecular subtype was determined (where possible by gene expression profiling) on study entry. Patients with the ABC versus the GCB subtype had a significantly superior overall response rate (83% vs. 13%; P = 0.0004) and median overall survival (OS; 10.8 vs. 3.4 months; P = 0.0026). The results of this study and others suggest that there is a basis for developing novel therapeutic strategies directed at individual molecular subtypes, and currently, randomized studies testing R-CHOP with or without bortezomib are under way in newly diagnosed patients with non–GCB DLBCL (Table 1; ref. 55).

Table 1.

Selected ongoing studies in newly diagnosed patients with DLBCL assessing the addition of novel agents to immunochemotherapy

StudyEligibilityArmsStudy agent
REMoDLB Newly diagnosed patients with DLBCL. Stage I bulky and stages II–IV. All receive 1 cycle of R-CHOP. Then, ABC patients are randomized. R-CHOP Bortezomib 
  vs.  
  R-CHOP-B  
PYRAMID Newly diagnosed non-GCB patients, all stages. R-CHOP Bortezomib 
  vs.  
  Vc-R-CHOP  
LYM2034 Newly diagnosed non-GCB patients, stages II–IV. R-CHOP Bortezomib 
  vs.  
  Vc-R-CAP  
PHOENIX Newly diagnosed non-GCB patients, stages II–IV. R-CHOP Ibrutinib 
  vs.  
  I-R-CHOP  
ECOG1412 Newly diagnosed DLBCL, stage II bulky disease and stages III–IV. R-CHOP Lenalidomide 
  vs.  
  R2-CHOP  
StudyEligibilityArmsStudy agent
REMoDLB Newly diagnosed patients with DLBCL. Stage I bulky and stages II–IV. All receive 1 cycle of R-CHOP. Then, ABC patients are randomized. R-CHOP Bortezomib 
  vs.  
  R-CHOP-B  
PYRAMID Newly diagnosed non-GCB patients, all stages. R-CHOP Bortezomib 
  vs.  
  Vc-R-CHOP  
LYM2034 Newly diagnosed non-GCB patients, stages II–IV. R-CHOP Bortezomib 
  vs.  
  Vc-R-CAP  
PHOENIX Newly diagnosed non-GCB patients, stages II–IV. R-CHOP Ibrutinib 
  vs.  
  I-R-CHOP  
ECOG1412 Newly diagnosed DLBCL, stage II bulky disease and stages III–IV. R-CHOP Lenalidomide 
  vs.  
  R2-CHOP  

Abbreviations: A, doxorubicin (Adriamycin); B, bortezomib; I, ibrutinib; R2-CHOP, rituximab, lenalidomide (Revlimid), CHOP; Vc, bortezomib (Velcade).

Over the past few years, our understanding of various mechanisms of NF-κB activation in ABC DLBCL has evolved significantly, and this has paved the way for the development of several new classes of agents that target NF-κB. In particular, recent work has underlined the importance of chronic B-cell receptor (BCR) signaling as well as activating mutations in CARD11 and MYD88 in driving NF-κB (Fig. 4; refs. 56–59). As a result, several specific inhibitors of critical pathways that drive NF-κB activation are in development (60). An important step in the activation of NF-κB by BCR signaling is regulated by Bruton tyrosine kinase (BTK), and several specific inhibitors of BTK are now in clinical development. One of these—ibrutinib—selectively kills cell lines with chronic active BCR signaling. Ibrutinib covalently inhibits BTK and is orally bioavailable (56). Recently, a multicenter study tested ibrutinib in 70 patients with relapsed and refractory DLBCL. Twenty-nine cases included had ABC DLBCL, 20 had GCB DLBCL, and 21 cases were “unclassifiable” (61). Interestingly, there was selective activity within the ABC group. Although the overall response rate was 23%, 41% of patients with ABC DLBCL responded compared with only 5% in the GCB group (P = 0.007); ABC patients also showed a trend toward better survival (than GCB patients; ref. 9; 76 vs. 3.35 months; P = 0.099). This selective activity of ibrutinib within the ABC subtype supports the role of BCR signaling in the activation of ABC DLBCL but not GCB DLBCL (56). One very interesting component of this study was the mutational status analysis of individual tumors. When correlated with outcome, tumors with BCR and MYD88 mutations had a high response rate, whereas those with CARD11 mutations did not, highlighting the dominance of downstream signaling in the latter group (61). On the basis of the selective activity of ibrutinib in ABC DLBCL, a randomized study of R-CHOP versus R-CHOP with ibrutinib is under way in newly diagnosed patients with non–GCB DLBCL (Table 1). Several other inhibitors of BTK are also in development (62).

Figure 4.

Map of BCR and MYD88 signaling pathways and potential targets. Signaling through BCR leads to downstream activation of the NF-κB transcription factor, which is a driver pathway in ABC DLBCL. Signaling also activates the AKT/MTOR and MAP kinase pathways. Constitutive MYD88 signaling is an alternative pathway leading to NF-κB activation. Reprinted from ref. 69. Cancer Cell, Vol. 21, Yang Y, Shaffer AL 3rd, Emre NC, Ceribelli M, Zhang M, Wright G, et al., Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma, p. 723–37. Copyright 2012, with permission from Elsevier.

Figure 4.

Map of BCR and MYD88 signaling pathways and potential targets. Signaling through BCR leads to downstream activation of the NF-κB transcription factor, which is a driver pathway in ABC DLBCL. Signaling also activates the AKT/MTOR and MAP kinase pathways. Constitutive MYD88 signaling is an alternative pathway leading to NF-κB activation. Reprinted from ref. 69. Cancer Cell, Vol. 21, Yang Y, Shaffer AL 3rd, Emre NC, Ceribelli M, Zhang M, Wright G, et al., Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma, p. 723–37. Copyright 2012, with permission from Elsevier.

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Several other kinase inhibitors that target ABC DLBCL are under investigation. Enzastaurin is an oral potent inhibitor of protein kinase C β, which is a serine/threonine kinase. It is amplified through the BCR signaling pathway and likely plays a critical role in NF-κB activation. However, recently, a phase III study investigating its activity in the prevention of relapse in DLBCL was stopped early as disease-free survival was no better than it was with placebo in patients at high risk of relapse following rituximab-based chemotherapy. Fostamatinib, an Syk inhibitor, has shown activity across a wide range of lymphomas including DLBCL but has not demonstrated selective activity within ABC DLBCL (63). The PI3K/AKT/mTOR signaling pathway appears to be important in these tumors as evidenced by the fact that both temsirolimus and everolimus, which inhibit mTOR, have induced remissions over several different lymphoma types (64–66). The optimal targets of this pathway are unknown, but upstream molecules, such as AKT or PI3K, may be particularly promising. Idelalisib is a potent inhibitor of PI3K p110δ and results in the blockade of constitutive PI3K signaling in vitro. Although it is effective in indolent B-cell lymphomas, it has not shown activity in DLBCL so far (67, 68). MYD88 is another potentially important target in ABC DLBCL as it is mutated in approximately 30% of cases (58). It activates NF-κB via a signaling cascade involving IRAK1 and IRAK4. IRAK4 activity is critical for the oncogenic effect of MYD88, and IRAK4 inhibitors have selective activity in ABC cell lines (58). These agents, therefore, represent another rational therapeutic strategy for ABC DLBCL.

Immunomodulatory agents such as lenalidomide are another interesting class to consider. Lenalidomide selectively kills ABC DLBCL cells in vitro by augmenting IFNβ production through its effects on IRF4 (69). It has selective activity in the ABC group as evidenced by a phase II study in relapsed and refractory DLBCL, in which the response rate was much higher in patients with ABC versus GCB DLBCL (55% compared with 9%; ref. 70). Lenalidomide has been safely combined with R-CHOP (R2-CHOP), and in two studies, the combination has demonstrated high efficacy in patients with newly diagnosed DLBCL (71, 72). In a recent report of 64 patients with DLBCL, there was no significant difference in the 24-month PFS and OS of GCB versus non-GCB patients who received R2-CHOP (73). In contrast, PFS and OS of the non-GCB group were significantly inferior in a comparison control group who received R-CHOP. On the basis of these results, a randomized phase II study is under way in previously untreated patients.

Approximately 10% of DLBCL cases harbor an MYC rearrangement, and this has been associated with an inferior outcome following R-CHOP chemotherapy (74–76). Cases that harbor an additional BCL2 (or BCL6) translocation have been termed “double-hit” lymphomas and have a particularly poor outcome following standard therapy (77). Most of these are of GCB derivation. At this time, optimal therapy for these diseases has not been defined and there is no definite role for upfront transplantation (78). Recently, there has been much interest in so-called “double-expressor” lymphomas that have high protein expression of MYC and BCL2 but without translocations. These are usually of non-GCB origin, and like “double-hit” lymphomas also have a poor outcome following standard therapy (79, 80). On the basis of efficacy in Burkitt lymphoma, the DA-EPOCH-R regimen was retrospectively assessed in both MYC-rearranged and MYC-negative DLBCL, and there was no difference in outcome between the two groups (81–83). A multicenter prospective study is under way to test the regimen in MYC-rearranged DLBCL. Strategies in development to specifically target MYC include small-molecule inhibitors of the bromodomain and extraterminal domain family (BET) chromatin–associated proteins such as JQ1 and I-BET 151. Although they have shown preclinical activity in tumors harboring rearrangements of MYC, they also seem to be active in nontranslocated cancers with deregulation of MYC at the posttranscriptional level (84). As Aurora kinase function is needed for the maintenance of MYC-driven lymphoma, Aurora kinase inhibitors are interesting agents and in development (85).

BCL2 is expressed in both GCB and ABC DLBCLs. It is typically associated with a t(14:18) translocation in GCB DLBCL and is a marker of NF-κB activation in ABC DLBCL. The association between BCL2 overexpression and outcome is complex—although older studies suggested that it portended a poor prognosis, more recent studies have not found this. Several specific inhibitors of BCL2, such as navitoclax and ABT-199, are in development (86).

PMBL comprises 10% of DLBCL cases and is predominantly diagnosed in young females. It arises in the mediastinum and is derived from a thymic B cell (21). Although it is recognized as a subtype of DLBCL, it clinically and molecularly resembles nodular sclerosing Hodgkin lymphoma arising in the mediastinum. Its molecular profile is very different from either GCB or ABC DLBCL and is much closer to nodular sclerosing Hodgkin lymphoma, with which it shares a third of its genes (24).

Because of the rarity of PMBL, there has been a lack of prospective studies and therefore poor consensus on how best to approach its management (22). Early studies, which were performed by Italian groups, suggested that mediastinal radiotherapy was a critical component of curative therapy and it continues to be widely used. One early study that established this standard tested MACOP-B (methotrexate, leucovorin, doxorubicin, cyclophosphamide, vincristine, prednisone, and bleomycin) followed by consolidative radiation therapy. Although 66% of patients were gallium positive at the end of chemotherapy, this reduced to 19% after mediastinal radiation, suggesting that radiation was critical (87). Dose intensity has always been considered to be important in PMBL therapeutics, and given the close relationship of PMBL to nodular sclerosing Hodgkin lymphoma—where dose intensity is beneficial—this is not unexpected (88). Many retrospective studies assessed the role of dose intensity, including one where MACOP-B and VACOP-B (etoposide, doxorubicin, cyclophosphamide, vincristine, prednisone, bleomycin) were compared with CHOP; the outcome in the CHOP group was inferior, suggesting a role for dose intensity in PMBL, and this was demonstrated in other studies (89–91). However, due to the rarity of PMBL, there have not been any prospective randomized studies of dose-intense versus conventional approaches.

Most studies have suggested a benefit to using rituximab in PMBL. In a subgroup analysis of the MabThera International Trial (MInT) that was confined to patients with PMBL, the additive benefit of rituximab in combination with CHOP-like regimens was assessed (92). Patients who received rituximab had a superior 3-year event-free survival (78% vs. 52% in the chemotherapy arm alone)—because of small numbers, an OS difference was not appreciated. Most patients in this analysis received preplanned mediastinal radiation which improved remission rates (93, 94). It is important to consider that the MInT study was confined to patients with a low IPI score (≤1) and therefore did not include the entire spectrum of patients with this disease. Other studies have evaluated R-CHOP in patients of all risk groups with the disease. One of these retrospectively evaluated 58 patients of all IPI groups treated with R-CHOP (followed by mediastinal radiation in 77% of responders; ref. 94). There was a high rate of primary induction failures (21%), and the overall PFS at 5 years was 68% (94). Another retrospective study evaluated R-CHOP followed by ifosfamide, cyclophosphamide, and etoposide without radiation and reported a PFS of 78% at 3 years (95). Recently, the International Extranodal Lymphoma Study Group reported a 5-year PFS rate of 86% in 125 patients with PMBL who received different immunochemotherapy regimens followed by radiation in the majority of cases (96).

Though combined modality treatment is very effective in PMBL, the addition of mediastinal radiation is clearly associated with significant long-term morbidities (97). The increased risk of breast cancer is particularly problematic. Although lower doses of radiation may reduce these risks, this has not been clearly demonstrated yet (98). In an attempt to develop a strategy that removed the need for radiation, an NCI study investigated the dose-adjusted EPOCH-R regimen without radiation in PMBL and included all risk groups of patients (37). In 51 patients, EFS and OS rates were 93% and 97%, respectively, at a median follow-up of 5 years, and consolidation mediastinal radiation was administered to just 2 patients (99). In 16 additional patients with PMBL who received the regimen at another center, EFS and OS were 100% without radiation. On the basis of these promising results, the approach is being tested by other groups, and an early report from a German pediatric/adolescent study demonstrated high efficacy without radiation (100). Future strategies in PMBL should continue to focus on reducing toxicity and testing rational and promising novel agents (101).

We are entering an era of precision treatment of distinct subtypes of DLBCL. Though once considered to be a single-disease entity, there is now recognition that DLBCL is clinically and molecularly heterogeneous and, importantly, distinct subtypes have disparate outcomes following standard therapy. One big challenge has been the ability to correctly diagnose molecular subtypes in the clinic, but recent studies have shown that quantitation of gene expression in FFPET is feasible with a very short turnaround time, suggesting broad applicability in the future. Recent studies have demonstrated that certain novel agents have differential activity within subtypes of DLBCL. There are now ongoing studies investigating distinct approaches within molecular subtypes of the disease. It is likely in the future that selection of upfront therapy for patients with DLBCL will be determined based on molecular phenotype.

No potential conflicts of interest were disclosed.

Conception and design: K. Dunleavy, W.H. Wilson

Development of methodology: W.H. Wilson

Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): W.H. Wilson

Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis): K. Dunleavy, W.H. Wilson

Writing, review, and/or revision of the manuscript: K. Dunleavy, M. Roschewski, W.H. Wilson

Study supervision: W.H. Wilson

1.
Coiffier
B
,
Thieblemont
C
,
Van Den Neste
E
,
Lepeu
G
,
Plantier
I
,
Castaigne
S
, et al
Long-term outcome of patients in the LNH-98.5 trial, the first randomized study comparing rituximab-CHOP to standard CHOP chemotherapy in DLBCL patients: a study by the Groupe d'Etudes des Lymphomes de l'Adulte
.
Blood
2010
;
116
:
2040
5
.
2.
Lohr
JG
,
Stojanov
P
,
Lawrence
MS
,
Auclair
D
,
Chapuy
B
,
Sougnez
C
, et al
Discovery and prioritization of somatic mutations in diffuse large B-cell lymphoma (DLBCL) by whole-exome sequencing
.
Proc Natl Acad Sci U S A
2012
;
109
:
3879
84
.
3.
Lenz
G
,
Wright
GW
,
Emre
NC
,
Kohlhammer
H
,
Dave
SS
,
Davis
RE
, et al
Molecular subtypes of diffuse large B-cell lymphoma arise by distinct genetic pathways
.
Proc Natl Acad Sci U S A
2008
;
105
:
13520
5
.
4.
Zhang
J
,
Grubor
V
,
Love
CL
,
Banerjee
A
,
Richards
KL
,
Mieczkowski
PA
, et al
Genetic heterogeneity of diffuse large B-cell lymphoma
.
Proc Natl Acad Sci U S A
2013
;
110
:
1398
403
.
5.
Shipp
MA
,
Ross
KN
,
Tamayo
P
,
Weng
AP
,
Kutok
JL
,
Aguiar
RC
, et al
Diffuse large B-cell lymphoma outcome prediction by gene-expression profiling and supervised machine learning
.
Nature Med
2002
;
8
:
68
74
.
6.
Alizadeh
AA
,
Eisen
MB
,
Davis
RE
,
Ma
C
,
Lossos
IS
,
Rosenwald
A
, et al
Distinct types of diffuse large B-cell lymphoma identified by gene expression profiling
.
Nature
2000
;
403
:
503
11
.
7.
Wright
G
,
Tan
B
,
Rosenwald
A
,
Hurt
EH
,
Wiestner
A
,
Staudt
LM
. 
A gene expression-based method to diagnose clinically distinct subgroups of diffuse large B cell lymphoma
.
Proc Natl Acad Sci U S A
2003
;
100
:
9991
6
.
8.
Bea
S
,
Zettl
A
,
Wright
G
,
Salaverria
I
,
Jehn
P
,
Moreno
V
, et al
Diffuse large B-cell lymphoma subgroups have distinct genetic profiles that influence tumor biology and improve gene-expression-based survival prediction
.
Blood
2005
;
106
:
3183
90
.
9.
Green
MR
,
Monti
S
,
Dalla-Favera
R
,
Pasqualucci
L
,
Walsh
NC
,
Schmidt-Supprian
M
, et al
Signatures of murine B-cell development implicate Yy1 as a regulator of the germinal center-specific program
.
Proc Natl Acad Sci U S A
2011
;
108
:
2873
8
.
10.
Abramson
JS
,
Shipp
MA
. 
Advances in the biology and therapy of diffuse large B-cell lymphoma: moving toward a molecularly targeted approach
.
Blood
2005
;
106
:
1164
74
.
11.
Lenz
G
,
Wright
G
,
Dave
SS
,
Xiao
W
,
Powell
J
,
Zhao
H
, et al
Stromal gene signatures in large-B-cell lymphomas
.
N Engl J Med
2008
;
359
:
2313
23
.
12.
Hans
CP
,
Weisenburger
DD
,
Greiner
TC
,
Gascoyne
RD
,
Delabie
J
,
Ott
G
, et al
Confirmation of the molecular classification of diffuse large B-cell lymphoma by immunohistochemistry using a tissue microarray
.
Blood
2004
;
103
:
275
82
.
13.
Choi
WW
,
Weisenburger
DD
,
Greiner
TC
,
Piris
MA
,
Banham
AH
,
Delabie
J
, et al
A new immunostain algorithm classifies diffuse large B-cell lymphoma into molecular subtypes with high accuracy
.
Clin Cancer Res
2009
;
15
:
5494
502
.
14.
Meyer
PN
,
Fu
K
,
Greiner
TC
,
Smith
LM
,
Delabie
J
,
Gascoyne
RD
, et al
Immunohistochemical methods for predicting cell of origin and survival in patients with diffuse large B-cell lymphoma treated with rituximab
.
J Clin Oncol
2011
;
29
:
200
7
.
15.
Coutinho
R
,
Clear
AJ
,
Owen
A
,
Wilson
A
,
Matthews
J
,
Lee
A
, et al
Poor concordance among nine immunohistochemistry classifiers of cell-of-origin for diffuse large B-cell lymphoma: implications for therapeutic strategies
.
Clin Cancer Res
2013
;
19
:
6686
95
.
16.
Culpin
RE
,
Sieniawski
M
,
Angus
B
,
Menon
GK
,
Proctor
SJ
,
Milne
P
, et al
Prognostic significance of immunohistochemistry-based markers and algorithms in immunochemotherapy-treated diffuse large B cell lymphoma patients
.
Histopathology
2013
;
63
:
788
801
.
17.
Gutierrez-Garcia
G
,
Cardesa-Salzmann
T
,
Climent
F
,
Gonzalez-Barca
E
,
Mercadal
S
,
Mate
JL
, et al
Gene-expression profiling and not immunophenotypic algorithms predicts prognosis in patients with diffuse large B-cell lymphoma treated with immunochemotherapy
.
Blood
2011
;
117
:
4836
43
.
18.
Ott
G
,
Ziepert
M
,
Klapper
W
,
Horn
H
,
Szczepanowski
M
,
Bernd
HW
, et al
Immunoblastic morphology but not the immunohistochemical GCB/nonGCB classifier predicts outcome in diffuse large B-cell lymphoma in the RICOVER-60 trial of the DSHNHL
.
Blood
2010
;
116
:
4916
25
.
19.
Scott
DW
,
Wright
GW
,
Williams
PM
,
Lih
CJ
,
Walsh
W
,
Jaffe
ES
, et al
Determining cell-of-origin subtypes of diffuse large B-cell lymphoma using gene expression in formalin-fixed paraffin-embedded tissue
.
Blood
2014
;
123
:
1214
7
.
20.
Pasqualucci
L
,
Migliazza
A
,
Basso
K
,
Houldsworth
J
,
Chaganti
RS
,
Dalla-Favera
R
. 
Mutations of the BCL6 proto-oncogene disrupt its negative autoregulation in diffuse large B-cell lymphoma
.
Blood
2003
;
101
:
2914
23
.
21.
Swerdlow
S
,
Campo
E
,
Harris
NL
,
Jaffe
ES
,
Pileri
SA
,
Stein
H
, et al
editors
. 
WHO classification of tumours of haematopoeitic and lymphoid tissues
. 4th ed.
Lyon (France)
:
IARC Press
; 
2008
.
22.
Dunleavy
K
,
Grant
C
,
Eberle
FC
,
Pittaluga
S
,
Jaffe
ES
,
Wilson
WH
. 
Gray zone lymphoma: better treated like Hodgkin lymphoma or mediastinal large B-cell lymphoma?
Curr Hematol Malig Rep
2012
;
7
:
241
7
.
23.
Gunawardana
J
,
Chan
FC
,
Telenius
A
,
Woolcock
B
,
Kridel
R
,
Tan
KL
, et al
Recurrent somatic mutations of PTPN1 in primary mediastinal B cell lymphoma and Hodgkin lymphoma
.
Nat Genet
2014
;
46
:
329
35
.
24.
Rosenwald
A
,
Wright
G
,
Leroy
K
,
Yu
X
,
Gaulard
P
,
Gascoyne
RD
, et al
Molecular diagnosis of primary mediastinal B cell lymphoma identifies a clinically favorable subgroup of diffuse large B cell lymphoma related to Hodgkin lymphoma
.
J Exp Med
2003
;
198
:
851
62
.
25.
Wilson
WH
,
Pittaluga
S
,
Nicolae
A
,
Camphausen
K
,
Shovlin
M
,
Steinberg
SM
, et al
A prospective study of mediastinal gray zone lymphoma
.
Blood
2014
;
124
:
1563
9
.
26.
Fisher
RI
,
Gaynor
ER
,
Dahlberg
S
,
Oken
MM
,
Grogan
TM
,
Mize
EM
, et al
Comparison of a standard regimen (CHOP) with three intensive chemotherapy regimens for advanced non-Hodgkin's lymphoma
.
N Engl J Med
1993
;
328
:
1002
6
.
27.
Pfreundschuh
M
,
Trumper
L
,
Kloess
M
,
Schmits
R
,
Feller
AC
,
Rube
C
, et al
Two-weekly or 3-weekly CHOP chemotherapy with or without etoposide for the treatment of elderly patients with aggressive lymphomas: results of the NHL-B2 trial of the DSHNHL
.
Blood
2004
;
104
:
634
41
.
28.
Pfreundschuh
M
,
Trumper
L
,
Kloess
M
,
Schmits
R
,
Feller
AC
,
Rudolph
C
, et al
Two-weekly or 3-weekly CHOP chemotherapy with or without etoposide for the treatment of young patients with good-prognosis (normal LDH) aggressive lymphomas: results of the NHL-B1 trial of the DSHNHL
.
Blood
2004
;
104
:
626
33
.
29.
Pfreundschuh
M
,
Trumper
L
,
Osterborg
A
,
Pettengell
R
,
Trneny
M
,
Imrie
K
, et al
CHOP-like chemotherapy plus rituximab versus CHOP-like chemotherapy alone in young patients with good-prognosis diffuse large-B-cell lymphoma: a randomised controlled trial by the MabThera International Trial (MInT) Group
.
Lancet Oncol
2006
;
7
:
379
91
.
30.
Pfreundschuh
M
,
Schubert
J
,
Ziepert
M
,
Schmits
R
,
Mohren
M
,
Lengfelder
E
, et al
Six versus eight cycles of bi-weekly CHOP-14 with or without rituximab in elderly patients with aggressive CD20+ B-cell lymphomas: a randomised controlled trial (RICOVER-60)
.
Lancet Oncol
2008
;
9
:
105
16
.
31.
Coiffier
B
,
Lepage
E
,
Briere
J
,
Herbrecht
R
,
Tilly
H
,
Bouabdallah
R
, et al
CHOP chemotherapy plus rituximab compared with CHOP alone in elderly patients with diffuse large-B-cell lymphoma
.
N Engl J Med
2002
;
346
:
235
42
.
32.
Cunningham
D
,
Hawkes
EA
,
Jack
A
,
Qian
W
,
Smith
P
,
Mouncey
P
, et al
Rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone in patients with newly diagnosed diffuse large B-cell non-Hodgkin lymphoma: a phase 3 comparison of dose intensification with 14-day versus 21-day cycles
.
Lancet
2013
;
381
:
1817
26
.
33.
Delarue
R
,
Tilly
H
,
Mounier
N
,
Petrella
T
,
Salles
G
,
Thieblemont
C
, et al
Dose-dense rituximab-CHOP compared with standard rituximab-CHOP in elderly patients with diffuse large B-cell lymphoma (the LNH03–6B study): a randomised phase 3 trial
.
Lancet Oncol
2013
;
14
:
525
33
.
34.
Récher
C
,
Coiffier
B
,
Haioun
C
,
Molina
TJ
,
Fermé
C
,
Casasnovas
O
, et al
Intensified chemotherapy with ACVBP plus rituximab versus standard CHOP plus rituximab for the treatment of diffuse large B-cell lymphoma (LNH03–2B): an open-label randomised phase 3 trial
.
Lancet
2011
;
378
:
1858
67
.
35.
Holte
H
,
Leppa
S
,
Bjorkholm
M
,
Fluge
O
,
Jyrkkio
S
,
Delabie
J
, et al
Dose-densified chemoimmunotherapy followed by systemic central nervous system prophylaxis for younger high-risk diffuse large B-cell/follicular grade 3 lymphoma patients: results of a phase II Nordic Lymphoma Group study
.
Ann Oncol
2013
;
24
:
1385
92
.
36.
Wilson
WH
,
Grossbard
ML
,
Pittaluga
S
,
Cole
D
,
Pearson
D
,
Drbohlav
N
, et al
Dose-adjusted EPOCH chemotherapy for untreated large B-cell lymphomas: a pharmacodynamic approach with high efficacy
.
Blood
2002
;
99
:
2685
93
.
37.
Wilson
WH
,
Dunleavy
K
,
Pittaluga
S
,
Hegde
U
,
Grant
N
,
Steinberg
SM
, et al
Phase II study of dose-adjusted EPOCH and rituximab in untreated diffuse large B-cell lymphoma with analysis of germinal center and post-germinal center biomarkers
.
J Clin Oncol
2008
;
26
:
2717
24
.
38.
Oschlies
I
,
Klapper
W
,
Zimmermann
M
,
Krams
M
,
Wacker
HH
,
Burkhardt
B
, et al
Diffuse large B-cell lymphoma in pediatric patients belongs predominantly to the germinal-center type B-cell lymphomas: a clinicopathologic analysis of cases included in the German BFM (Berlin-Frankfurt-Munster) Multicenter Trial
.
Blood
2006
;
107
:
4047
52
.
39.
Basso
K
,
Dalla-Favera
R
. 
Roles of BCL6 in normal and transformed germinal center B cells
.
Immunol Rev
2012
;
247
:
172
83
.
40.
Cerchietti
L
,
Melnick
A
. 
Targeting BCL6 in diffuse large B-cell lymphoma: what does this mean for the future treatment?
Expert Rev Hematol
2013
;
6
:
343
5
.
41.
Cerchietti
LC
,
Ghetu
AF
,
Zhu
X
,
Da Silva
GF
,
Zhong
S
,
Matthews
M
, et al
A small-molecule inhibitor of BCL6 kills DLBCL cells in vitro and in vivo
.
Cancer Cell
2010
;
17
:
400
11
.
42.
Granadino-Roldan
JM
,
Obiol-Pardo
C
,
Pinto
M
,
Garzon
A
,
Rubio-Martinez
J
. 
Molecular dynamics analysis of the interaction between the human BCL6 BTB domain and its SMRT, NcoR and BCOR corepressors: the quest for a consensus dynamic pharmacophore
.
J Mol Graph Model
2014
;
50
:
142
51
.
43.
Pasqualucci
L
,
Dominguez-Sola
D
,
Chiarenza
A
,
Fabbri
G
,
Grunn
A
,
Trifonov
V
, et al
Inactivating mutations of acetyltransferase genes in B-cell lymphoma
.
Nature
2011
;
471
:
189
95
.
44.
Amengual
JE
,
Clark-Garvey
S
,
Kalac
M
,
Scotto
L
,
Marchi
E
,
Neylon
E
, et al
Sirtuin and pan-class I/II deacetylase (DAC) inhibition is synergistic in preclinical models and clinical studies of lymphoma
.
Blood
2013
;
122
:
2104
13
.
45.
Kurosu
T
,
Fukuda
T
,
Miki
T
,
Miura
O
. 
BCL6 overexpression prevents increase in reactive oxygen species and inhibits apoptosis induced by chemotherapeutic reagents in B-cell lymphoma cells
.
Oncogene
2003
;
22
:
4459
68
.
46.
Dunleavy
K
,
Little
RF
,
Pittaluga
S
,
Grant
N
,
Wayne
AS
,
Carrasquillo
JA
, et al
The role of tumor histogenesis, FDG-PET, and short-course EPOCH with dose-dense rituximab (SC-EPOCH-RR) in HIV-associated diffuse large B-cell lymphoma
.
Blood
2010
;
115
:
3017
24
.
47.
Wilson
WH
,
Jung
SH
,
Porcu
P
,
Hurd
D
,
Johnson
J
,
Martin
SE
, et al
A Cancer and Leukemia Group B multi-center study of DA-EPOCH-rituximab in untreated diffuse large B-cell lymphoma with analysis of outcome by molecular subtype
.
Haematologica
2012
;
97
:
758
65
.
48.
Morin
RD
,
Johnson
NA
,
Severson
TM
,
Mungall
AJ
,
An
J
,
Goya
R
, et al
Somatic mutations altering EZH2 (Tyr641) in follicular and diffuse large B-cell lymphomas of germinal-center origin
.
Nat Genet
2010
;
42
:
181
5
.
49.
Garapaty-Rao
S
,
Nasveschuk
C
,
Gagnon
A
,
Chan
EY
,
Sandy
P
,
Busby
J
, et al
Identification of EZH2 and EZH1 small molecule inhibitors with selective impact on diffuse large B cell lymphoma cell growth
.
Chem Biol
2013
;
20
:
1329
39
.
50.
Bohers
E
,
Mareschal
S
,
Bouzelfen
A
,
Marchand
V
,
Ruminy
P
,
Maingonnat
C
, et al
Targetable activating mutations are very frequent in GCB and ABC diffuse large B-cell lymphoma
.
Genes Chromosomes Cancer
2014
;
53
:
144
53
.
51.
Fu
K
,
Weisenburger
DD
,
Choi
WW
,
Perry
KD
,
Smith
LM
,
Shi
X
, et al
Addition of rituximab to standard chemotherapy improves the survival of both the germinal center B-cell-like and non-germinal center B-cell-like subtypes of diffuse large B-cell lymphoma
.
J Clin Oncol
2008
;
26
:
4587
94
.
52.
Zucca
E
,
Bertoni
F
,
Vannata
B
,
Cavalli
F
. 
Emerging role of infectious etiologies in the pathogenesis of marginal zone B-cell lymphomas
.
Clin Cancer Res
2014
;
20
:
5207
16
.
53.
Davis
RE
,
Brown
KD
,
Siebenlist
U
,
Staudt
LM
. 
Constitutive nuclear factor kappaB activity is required for survival of activated B cell-like diffuse large B cell lymphoma cells
.
J Exp Med
2001
;
194
:
1861
74
.
54.
Dunleavy
K
,
Pittaluga
S
,
Czuczman
MS
,
Dave
SS
,
Wright
G
,
Grant
N
, et al
Differential efficacy of bortezomib plus chemotherapy within molecular subtypes of diffuse large B-cell lymphoma
.
Blood
2009
;
113
:
6069
76
.
55.
Ruan
J
,
Martin
P
,
Furman
RR
,
Lee
SM
,
Cheung
K
,
Vose
JM
, et al
Bortezomib plus CHOP-rituximab for previously untreated diffuse large B-cell lymphoma and mantle cell lymphoma
.
J Clin Oncol
2011
;
29
:
690
7
.
56.
Davis
RE
,
Ngo
VN
,
Lenz
G
,
Tolar
P
,
Young
RM
,
Romesser
PB
, et al
Chronic active B-cell-receptor signalling in diffuse large B-cell lymphoma
.
Nature
2010
;
463
:
88
92
.
57.
Lenz
G
,
Davis
RE
,
Ngo
VN
,
Lam
L
,
George
TC
,
Wright
GW
, et al
Oncogenic CARD11 mutations in human diffuse large B cell lymphoma
.
Science
2008
;
319
:
1676
9
.
58.
Ngo
VN
,
Young
RM
,
Schmitz
R
,
Jhavar
S
,
Xiao
W
,
Lim
KH
, et al
Oncogenically active MYD88 mutations in human lymphoma
.
Nature
2011
;
470
:
115
9
.
59.
Ceribelli
M
,
Kelly
PN
,
Shaffer
AL
,
Wright
GW
,
Xiao
W
,
Yang
Y
, et al
Blockade of oncogenic IkappaB kinase activity in diffuse large B-cell lymphoma by bromodomain and extraterminal domain protein inhibitors
.
Proc Natl Acad Sci U S A
2014
;
111
:
11365
70
.
60.
Fontan
L
,
Yang
C
,
Kabaleeswaran
V
,
Volpon
L
,
Osborne
MJ
,
Beltran
E
, et al
MALT1 small molecule inhibitors specifically suppress ABC-DLBCL in vitro and in vivo
.
Cancer Cell
2012
;
22
:
812
24
.
61.
Wilson
W
,
Gerecitano
J
,
Goy
A
,
Vos
Sd
,
Kenkre
V
,
Barr
P
, et al
The Bruton's Tyrosine Kinase (BTK) inhibitor, ibrutinib (PCI-32765), has preferential activity in the ABC subtype of relapsed/refractory de novo diffuse large B-cell lymphoma (DLBCL): interim results of a multicenter, open-label, phase 2 study [abstract]
.
Blood (ASH Annual Meeting Abstracts)
2012
;
120
:
686
.
62.
Hendriks
RW
,
Yuvaraj
S
,
Kil
LP
. 
Targeting Bruton's tyrosine kinase in B cell malignancies
.
Nat Rev Cancer
2014
;
14
:
219
32
.
63.
Friedberg
JW
,
Sharman
J
,
Sweetenham
J
,
Johnston
PB
,
Vose
JM
,
Lacasce
A
, et al
Inhibition of Syk with fostamatinib disodium has significant clinical activity in non-Hodgkin lymphoma and chronic lymphocytic leukemia
.
Blood
2010
;
115
:
2578
85
.
64.
Smith
SM
,
van Besien
K
,
Karrison
T
,
Dancey
J
,
McLaughlin
P
,
Younes
A
, et al
Temsirolimus has activity in non-mantle cell non-Hodgkin's lymphoma subtypes: The University of Chicago phase II consortium
.
J Clin Oncol
2010
;
28
:
4740
6
.
65.
Witzig
TE
,
Geyer
SM
,
Ghobrial
I
,
Inwards
DJ
,
Fonseca
R
,
Kurtin
P
, et al
Phase II trial of single-agent temsirolimus (CCI-779) for relapsed mantle cell lymphoma
.
J Clin Oncol
2005
;
23
:
5347
56
.
66.
Barnes
JA
,
Jacobsen
E
,
Feng
Y
,
Freedman
A
,
Hochberg
EP
,
LaCasce
AS
, et al
Everolimus in combination with rituximab induces complete responses in heavily pretreated diffuse large B-cell lymphoma
.
Haematologica
2013
;
98
:
615
9
.
67.
Gopal
AK
,
Kahl
BS
,
de Vos
S
,
Wagner-Johnston
ND
,
Schuster
SJ
,
Jurczak
WJ
, et al
PI3Kdelta inhibition by idelalisib in patients with relapsed indolent lymphoma
.
N Engl J Med
2014
;
370
:
1008
18
.
68.
Lannutti
BJ
,
Meadows
SA
,
Herman
SEM
,
Kashishian
A
,
Steiner
B
,
Johnson
AJ
, et al
CAL-101, a p110 selective phosphatidylinositol-3-kinase inhibitor for the treatment of B-cell malignancies, inhibits PI3K signaling and cellular viability
.
Blood
2010
;
117
:
591
4
.
69.
Yang
Y
,
Shaffer
AL
 3rd
,
Emre
NC
,
Ceribelli
M
,
Zhang
M
,
Wright
G
, et al
Exploiting synthetic lethality for the therapy of ABC diffuse large B cell lymphoma
.
Cancer Cell
2012
;
21
:
723
37
.
70.
Hernandez-Ilizaliturri
FJ
,
Deeb
G
,
Zinzani
PL
,
Pileri
SA
,
Malik
F
,
Macon
WR
, et al
Higher response to lenalidomide in relapsed/refractory diffuse large B-cell lymphoma in nongerminal center B-cell-like than in germinal center B-cell-like phenotype
.
Cancer
2011
;
117
:
5058
66
.
71.
Nowakowski
GS
,
LaPlant
B
,
Habermann
TM
,
Rivera
CE
,
Macon
WR
,
Inwards
DJ
, et al
Lenalidomide can be safely combined with R-CHOP (R2CHOP) in the initial chemotherapy for aggressive B-cell lymphomas: phase I study
.
Leukemia
2011
;
25
:
1877
81
.
72.
Vitolo
U
,
Chiappella
A
,
Franceschetti
S
,
Carella
AM
,
Baldi
I
,
Inghirami
G
, et al
Lenalidomide plus R-CHOP21 in elderly patients with untreated diffuse large B-cell lymphoma: results of the REAL07 open-label, multicentre, phase 2 trial
.
Lancet Oncol
2014
;
15
:
730
7
.
73.
Nowakowski
GS
,
LaPlant
B
,
Macon
WR
,
Reeder
CB
,
Foran
JM
,
Nelson
GD
, et al
Effect of lenalidomide combined with R-CHOP (R2CHOP) on negative prognostic impact of non-germinal venter (non-GCB) phenotype in newly diagnosed diffuse large B-cell lymphoma: a phase 2 study
.
J Clin Oncol
32
:
5s
, 
2014
(
suppl; abstr 8520
).
74.
Klapper
W
,
Stoecklein
H
,
Zeynalova
S
,
Ott
G
,
Kosari
F
,
Rosenwald
A
, et al
Structural aberrations affecting the MYC locus indicate a poor prognosis independent of clinical risk factors in diffuse large B-cell lymphomas treated within randomized trials of the German High-Grade Non-Hodgkin's Lymphoma Study Group (DSHNHL)
.
Leukemia
2008
;
22
:
2226
9
.
75.
Savage
KJ
,
Johnson
NA
,
Ben-Neriah
S
,
Connors
JM
,
Sehn
LH
,
Farinha
P
, et al
MYC gene rearrangements are associated with a poor prognosis in diffuse large B-cell lymphoma patients treated with R-CHOP chemotherapy
.
Blood
2009
;
114
:
3533
7
.
76.
Lai
C
,
Grant
C
,
Dunleavy
K
. 
Interpreting MYC and BCL2 in diffuse large B-cell lymphoma
.
Leuk Lymphoma
2013
;
54
:
2091
2
.
77.
Barrans
S
,
Crouch
S
,
Smith
A
,
Turner
K
,
Owen
R
,
Patmore
R
, et al
Rearrangement of MYC is associated with poor prognosis in patients with diffuse large B-cell lymphoma treated in the era of rituximab
.
J Clin Oncol
2010
;
28
:
3360
5
.
78.
Oki
Y
,
Noorani
M
,
Lin
P
,
Davis
RE
,
Neelapu
SS
,
Ma
L
, et al
Double hit lymphoma: the MD Anderson Cancer Center clinical experience
.
Br J Haematol
2014
;
166
:
891
901
.
79.
Johnson
NA
,
Slack
GW
,
Savage
KJ
,
Connors
JM
,
Ben-Neriah
S
,
Rogic
S
, et al
Concurrent expression of MYC and BCL2 in diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone
.
J Clin Oncol
2012
;
30
:
3452
9
.
80.
Green
TM
,
Young
KH
,
Visco
C
,
Xu-Monette
ZY
,
Orazi
A
,
Go
RS
, et al
Immunohistochemical double-hit score is a strong predictor of outcome in patients with diffuse large B-cell lymphoma treated with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone
.
J Clin Oncol
2012
;
30
:
3460
7
.
81.
Dunleavy
K
,
Pittaluga
S
,
Shovlin
M
,
Steinberg
SM
,
Cole
D
,
Grant
C
, et al
Low-intensity therapy in adults with Burkitt's lymphoma
.
N Engl J Med
2013
;
369
:
1915
25
.
82.
Dunleavy
K
,
Pittaluga
S
,
Wayne
A
,
Shovlin
M
,
Johnson
J
,
Little
R
, et al
MYC +aggressive B-cell lymphomas: novel therapy of untreated Burkitt lymphoma (BL) and MYC + diffuse large B-cell lymphoma (DLBCL) with DA-EPOCH-R [abstract]
.
Ann Oncol
2011
;
22
Suppl 4
:
iv6. Abstract nr 71
.
83.
Hu
S
,
Xu-Monette
ZY
,
Tzankov
A
,
Green
T
,
Wu
L
,
Balasubramanyam
A
, et al
MYC/BCL2 protein coexpression contributes to the inferior survival of activated B-cell subtype of diffuse large B-cell lymphoma and demonstrates high-risk gene expression signatures: a report from The International DLBCL Rituximab-CHOP Consortium Program
.
Blood
2013
;
121
:
4021
31
.
84.
Tolani
B
,
Gopalakrishnan
R
,
Punj
V
,
Matta
H
,
Chaudhary
PM
. 
Targeting Myc in KSHV-associated primary effusion lymphoma with BET bromodomain inhibitors
.
Oncogene
2014
;
29
:
2928
37
.
85.
Friedberg
JW
,
Mahadevan
D
,
Cebula
E
,
Persky
D
,
Lossos
I
,
Agarwal
AB
, et al
Phase II study of alisertib, a selective Aurora A kinase inhibitor, in relapsed and refractory aggressive B- and T-cell non-Hodgkin lymphomas
.
J Clin Oncol
2014
;
32
:
44
50
.
86.
Wilson
WH
,
O'Connor
OA
,
Czuczman
MS
,
LaCasce
AS
,
Gerecitano
JF
,
Leonard
JP
, et al
Navitoclax, a targeted high-affinity inhibitor of BCL-2, in lymphoid malignancies: a phase 1 dose-escalation study of safety, pharmacokinetics, pharmacodynamics, and antitumour activity
.
Lancet Oncol
2010
;
11
:
1149
59
.
87.
Zinzani
PL
,
Martelli
M
,
Magagnoli
M
,
Pescarmona
E
,
Scaramucci
L
,
Palombi
F
, et al
Treatment and clinical management of primary mediastinal large B-cell lymphoma with sclerosis: MACOP-B regimen and mediastinal radiotherapy monitored by (67)Gallium scan in 50 patients
.
Blood
1999
;
94
:
3289
93
.
88.
Diehl
V
,
Franklin
J
,
Pfreundschuh
M
,
Lathan
B
,
Paulus
U
,
Hasenclever
D
, et al
Standard and increased-dose BEACOPP chemotherapy compared with COPP-ABVD for advanced Hodgkin's disease
.
N Engl J Med
2003
;
348
:
2386
95
.
89.
Todeschini
G
,
Secchi
S
,
Morra
E
,
Vitolo
U
,
Orlandi
E
,
Pasini
F
, et al
Primary mediastinal large B-cell lymphoma (PMLBCL): long-term results from a retrospective multicentre Italian experience in 138 patients treated with CHOP or MACOP-B/VACOP-B
.
Br J Cancer
2004
;
90
:
372
6
.
90.
Zinzani
PL
,
Martelli
M
,
Bertini
M
,
Gianni
AM
,
Devizzi
L
,
Federico
M
, et al
Induction chemotherapy strategies for primary mediastinal large B-cell lymphoma with sclerosis: a retrospective multinational study on 426 previously untreated patients
.
Haematologica
2002
;
87
:
1258
64
.
91.
Hamlin
PA
,
Portlock
CS
,
Straus
DJ
,
Noy
A
,
Singer
A
,
Horwitz
SM
, et al
Primary mediastinal large B-cell lymphoma: optimal therapy and prognostic factor analysis in 141 consecutive patients treated at Memorial Sloan Kettering from 1980 to 1999
.
Br J Haematol
2005
;
130
:
691
9
.
92.
Rieger
M
,
Osterborg
A
,
Pettengell
R
,
White
D
,
Gill
D
,
Walewski
J
, et al
Primary mediastinal B-cell lymphoma treated with CHOP-like chemotherapy with or without rituximab: results of the Mabthera International Trial Group study
.
Ann Oncol
2011
;
22
:
664
70
.
93.
Vassilakopoulos
TP
,
Pangalis
GA
,
Katsigiannis
A
,
Papageorgiou
SG
,
Constantinou
N
,
Terpos
E
, et al
Rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone with or without radiotherapy in primary mediastinal large B-cell lymphoma: the emerging standard of care
.
Oncologist
2012
;
17
:
239
49
.
94.
Soumerai
JD
,
Hellmann
MD
,
Feng
Y
,
Sohani
AR
,
Toomey
CE
,
Barnes
JA
, et al
Treatment of primary mediastinal B-cell lymphoma with rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone is associated with a high rate of primary refractory disease
.
Leuk Lymphoma
2014
;
55
:
538
43
.
95.
Moskowitz
C
,
Hamlin
PA
,
Maraguilia
J
,
Meikle
J
,
Zelenetz
AD
. 
Sequential dose-dende R-CHOP followed by ICE consolidation (MSKCC Protocol 01–142) without radiotherapy for patients with primary mediastinal large B-cell lymphoma [abstract]
.
Blood (ASH Annual Meeting Abstracts)
2010
;
116
:
420
.
96.
Martelli
M
,
Ceriani
L
,
Zucca
E
,
Zinzani
PL
,
Ferreri
AJ
,
Vitolo
U
, et al
[18F]fluorodeoxyglucose positron emission tomography predicts survival after chemoimmunotherapy for primary mediastinal large B-cell lymphoma: results of the International Extranodal Lymphoma Study Group IELSG-26 Study
.
J Clin Oncol
2014
;
32
:
1769
75
.
97.
Castellino
SM
,
Geiger
AM
,
Mertens
AC
,
Leisenring
WM
,
Tooze
JA
,
Goodman
P
, et al
Morbidity and mortality in long-term survivors of Hodgkin lymphoma: a report from the Childhood Cancer Survivor Study
.
Blood
2011
;
117
:
1806
16
.
98.
O'Brien
MM
,
Donaldson
SS
,
Balise
RR
,
Whittemore
AS
,
Link
MP
. 
Second malignant neoplasms in survivors of pediatric Hodgkin's lymphoma treated with low-dose radiation and chemotherapy
.
J Clin Oncol
2010
;
28
:
1232
9
.
99.
Dunleavy
K
,
Pittaluga
S
,
Maeda
LS
,
Advani
R
,
Chen
CC
,
Hessler
J
, et al
Dose-adjusted EPOCH-rituximab therapy in primary mediastinal B-cell lymphoma
.
N Engl J Med
2013
;
368
:
1408
16
.
100.
Woessmann
W
,
Lisfeld
J
,
Burkhardt
B
. 
Therapy in primary mediastinal B-cell lymphoma
.
N Engl J Med
2013
;
369
:
282
.
101.
Ritz
O
,
Rommel
K
,
Dorsch
K
,
Kelsch
E
,
Melzner
J
,
Buck
M
, et al
STAT6-mediated BCL6 repression in primary mediastinal B-cell lymphoma (PMBL)
.
Oncotarget
2013
;
4
:
1093
102
.
102.
Lenz
G
,
Staudt
LM
. 
Aggressive lymphomas
.
N Engl J Med
2010
;
362
:
1417
29
.