PD-L1 upregulation is associated with activation of the DNA double-strand break repair pathway in patients with colitic cancer

Abstract Ulcerative colitis (UC) is a DNA damage-associated chronic inflammatory disease; the double-strand break (DSB) repair pathway participates in UC-associated dysplasia/colitic cancer carcinogenesis. The DSB/interferon regulatory factor-1 (IRF-1) can induce PD-L1 expression transcriptionally. However, association of PD-L1/DSB/IRF-1 with sporadic colorectal (SCRC), and cancer, remains elusive. Therefore, we investigated significance PD-L1/DSB using samples from 17 SCRC 12 UC patients rare cases by immunohistochemical analysis. We compared between determined CD8+ T-cell/DSB/IRF-1 axis cancer. was higher than normal mucosa or SCRC, CD8-positive T lymphocytes SCRC. Moreover, upregulation associated γH2AX (DSB marker) IRF-1 but not Multicolour immunofluorescence staining validated γH2AX/IRF-1/PD-L1 co-expression colitic tissue sections. Thus, immune cell-induced inflammation might activate DSB/IRF-1 axis, potentially serving as primary mechanism