Programmed Cell Death Ligand 1 Expression Is an Independent Prognostic Factor in Colorectal Cancer.

Abstract

Programmed cell death protein 1 (PD-1)/ programmed cell death ligand 1(PD-L1) axis is associated with immune tolerance via inhibition of T cell activation. The aim of this study was to clarify the significance of PD-1 and PD-L1 expressions and analyze the relationships between PD-1, PD-L1, transforming growth factor-β (TGF-β) and Forkhead box P3 (Foxp3) expressions in colorectal cancer (CRC). A total of 116 patients who underwent curative colectomy for stage II/III CRC were included in the study. PD-1, PD-L1, TGF-β, and Foxp3 expressions were examined by immunohistochemistry and related to prognostic factors by Kaplan-Meier. PD-1 expression was correlated with PD-L1, TGF-β, and Foxp3 expressions. Overall survival rates were significantly poorer in the PD-1 and PD-L1-positive groups. Multivariate analysis showed that PD-L1-positive is an independent risk factor. Disease-free survival (DFS) was tended in the PD-L1-positive group. The group with double-positive expression had significantly poorer prognosis. PD-1 and PD-L1 expressions were associated with a poor prognosis and correlated with TGF-β and Foxp3 expressions in patients with CRC.