CD274 and neoplasm: POLE-mutant and MSI tumors showed markedly increased infiltration of PD-L1+ immune cells within the tumor center compare with NSMP and p53-mutant tumors (POLE vs NSMP p < 0.001, POLE vs p53 p < 0.001, MSI vs NSMP p < 0.001, MSI vs p53 p = 0.002, Fig. 3C).