Purpose:

To ask whether the expression of immune markers and IFN signaling in tumor biopsies changes during concurrent chemoradiotherapy (CCRT).

Experimental Design:

Tumor biopsies and peripheral mononuclear blood cells (PMBC) before and immediately after 20 Gy/10 fractions (F) of radiation treatment (RT) from 30 patients with cervical cancer receiving CCRT were evaluated by IHC and qRT-PCR for immune markers and correlated with the short-term response.

Results:

Tumor immune response to radiation before and after 10F RT as reflected by CD8+ T-cell infiltration had substantial heterogeneity with increases, decreases, and no change all evident. Increases in CD8+ T cells during CCRT correlated with the presence of nuclear IRF1 in tumor cells (r = 0.68, P < 0.0001) and the patient short-term response (P < 0.01). Similarly, in a subset of patients (∼40%) PD-L1 positivity in tumor cells increased, which also correlated with nuclear IRF1 staining (r = 0.48, P < 0.01). Patients with augmented PMBC IFN signature expression after 10F had a significantly higher probability of PD-L1 induction (83% vs. 7%, P < 0.0001). Most patients exhibited abundant expression of SERPINB9 and CD47 in tumor cells, and tumor infiltration by CD68+ cells. SERPINB9 expression correlated with STAT1 signaling in tumor cells.

Conclusions:

CCRT leads to differential tumor immunogenicity and IFN signaling in patients with cervical cancer, suggesting radiation induction of immunity is limited to a subset of patients and may reflect the heterogeneity of intratumoral induction of IFNs.

See related commentary by Mondini and Deutsch, p. 3815

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