CD274 and neoplasm: PD-L1 expression was more frequent in POLE and MSI tumors compared with MSS tumors in both intraepithelial immune cells based on presence vs total absence (P=0.02) and in peritumoral immune cells based on at least 10% expression (84% vs 56%, P=0.03), PD-L1 expression did not show significant difference in tumor cells among POLE, MSI, and MSS ECs.