Circulating Inflammation Markers and Risk of Gastric and Esophageal Cancers: A Case–Cohort Study Within the Japan Public Health Center–Based Prospective Study

Chronic inflammation is a recognized etiology of upper gastrointestinal tract cancers, major causes of morbidity and mortality worldwide. In carcinogenesis of the noncardia (distal) stomach, mucosal colonization by Helicobacter pylori (H. pylori) induces chronic inflammation that may variably progress to atrophy, intestinal metaplasia, dysplasia, and adenocarcinoma (1). On the other hand, the bacterial infection is inversely or not at all related to cardia (proximal stomach) and esophageal cancers in most populations. Smoking and alcohol consumption are additional risk factors for cancers of both of these organs (2).

Mucosal injury and regeneration are characterized by a complex interaction of signaling molecules, including pro- and anti-inflammatory cytokines, soluble receptors, and angiogenesis and growth factors. Circulating levels of these proteins may be informative either as markers of local activity or through systemic effects. We therefore evaluated their associations with gastric and esophageal cancer risks in a prospective study.

The Japan Public Health Center–Based Prospective (JPHC) Study Cohort II is an ongoing study of middle-aged adults enrolled in 1993 to 1994, including 23,335 who donated baseline blood samples (3). Participants were followed for cancer through December, 2010. For this case–cohort analysis, a subcohort of 774 individuals was selected by age- and sex-stratified random sampling. A total of 446 gastric cancers (ICD-O codes C16.0–C16.9) and 68 esophageal cancers (ICD-O codes C15); mainly representing esophageal squamous cell carcinomas (ESCC) were identified among the blood donors, including 27 cases among members of the subcohort. Informed written consent was obtained from all the individuals. The JPHC study was institutional review board approved and conducted in accordance with recognized ethical guidelines.

Circulating levels of 64 inflammation-related biomarkers were measured in heparinized plasma using five Luminex bead-based multiplex assay panels (cytokine I, cytokine II, soluble receptors, cardiovascular disease, and high sensitivity T cell; EMD-Millipore Inc). Two biomarkers (IL3 and TNFβ) detected in <10% of samples were excluded from analysis.

Biomarkers were analyzed as ordinal variables (two to four categories depending upon proportion of measurements below the lower limit of detection) based on distributions among the subcohort members. Cox proportional regression models with a baseline hazard stratified by age group and sex were used to calculate HRs and 95% confidence intervals (CI) for association of each biomarker with cancer risks, accounting for the case–cohort design (4). Age was used as the model time metric. FDR-corrected P values were also calculated to adjust for multiple comparisons. We performed stratified analyses by latency from blood collection to cancer diagnosis (<5 vs. ≥5 years) and by gastric anatomic subsite (proximal vs. distal). We also restricted to seropositive H. pylori subcohort members as a sensitivity analysis. Tests of statistical significance were based on two-sided P <0.05. All analyses were performed using SAS software version 9.4 (SAS Inc).

Baseline characteristics of subcohort members and cases are presented in Table 1. The median time from blood collection to disease diagnosis was 8.1 years [interquartile range (IQR), 4.2–12.7 years] for gastric cancer and 9.4 years (IQR, 5.1–13.0 years) for esophageal cancer. Compared with subcohort members, gastric cancer cases had higher frequencies of gastric cancer family history, cigarette smoking, and salty foods consumption, while esophageal cancer cases had higher percentages of smoking and alcohol use.

Figure 1 shows the 62 evaluable biomarkers and their associations with risks of (A) gastric and (B) esophageal cancer. Levels of sEGFR (P_trend = 0.017) and TSLP (P_trend = 0.048) were nominally associated with gastric cancer risk, and CRP (P_trend = 0.015), CXCL11/ITAC (P_trend = 0.017), and CCL15/MIP1D (P_trend = 0.043) with esophageal cancer. However, none of the P_trends remained statistically significant with FDR correction. Neither stratified analysis by latency nor restriction to H. pylori seropositive cohort members revealed any significant associations. HRs for proximal and distal cancers were similar to gastric cancer overall.

Despite the well-known role of local inflammation in gastroesophageal cancers, systemic levels of inflammatory proteins were not associated with incidence of these tumors during almost two decades of follow-up. Even within 5 years of cancer diagnosis, when effects of early disease may be manifest, circulating levels were unremarkable. Our multiplex method to assess the biomarkers is extensively validated. Other study strengths include the population-based design, large numbers of cases, and adjustment for relevant risk factors.

Our findings for gastric cancer did not replicate previously reported modest associations based on plasma samples from the first JPHC cohort for CRP and SAA (494 case–control pairs; ref. 5), and in the Shanghai Health Cohorts for IL8 among men (180 cases vs. 358 controls; ref. 6), and IL6 among women (141 cases vs. 282 controls; ref. 7). For esophageal cancer, our findings differ from the results of the Iranian Golestan Cohort study, which found strong associations in a relative small-sample set (36 ESCC cases vs. 81 controls) with 15 of the markers we evaluated (8).

In conclusion, our study did not identify systemic markers for gastroesophageal cancers. Given the complexity of the immune response, these findings do not preclude potential associations with other inflammation-related molecules. Further study is warranted to identify underlying mechanisms of digestive tract carcinogenesis that could eventually yield to targeted prevention and treatment approaches.

No potential conflicts of interest were disclosed.

Conception and design: M.C. Camargo, A. Hildesheim, S. Tsugane, C.S. Rabkin

Development of methodology: A. Hildesheim, C.S. Rabkin

Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): T. Shimazu, H. Charvat, T. Yamaji, N. Sawada, T.J. Kemp, S. Tsugane

Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis): M.C. Camargo, M. Song, R.M. Pfeiffer, A. Hildesheim, S. Tsugane, C.S. Rabkin

Writing, review, and/or revision of the manuscript: M.C. Camargo, M. Song, T. Shimazu, N. Sawada, R.M. Pfeiffer, A. Hildesheim, S. Tsugane, H. Charvat, T. Yamaji, C.S. Rabkin

Administrative, technical, or material support (i.e., reporting or organizing data, constructing databases): T. Shimazu, N. Sawada, L.A. Pinto, S. Tsugane

Study supervision: A. Hildesheim, S. Tsugane, C.S. Rabkin

This study was supported by the Japanese National Cancer Center Research and Development Fund (grant no. 29-A-4, principal investigator, S. Tsugane) and the Intramural Research Program of the U.S. NCI (ZIA CP010212-10101, principal investigator, C.S. Rabkin). We acknowledge statistical assistance from Michael Curry, Information Management Services, Inc. The authors are also grateful to the Ibaraki, Niigata, Osaka, Kochi, Nagasaki, and Okinawa Cancer Registries for providing their incidence data. Members of the JPHC Study Group (principal investigator, S. Tsugane) are listed at https://epi.ncc.go.jp/en/jphc/781/7951.html

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