PDCD1 and neoplasm: The cell apoptotic rate was significantly increased in the K7M2-NC + PD-1+ group following treatment with anti-PD-1 antibody and cisplatin alone or jointly, as compared to the K7M2-LV + PD-1+ group (P < 0.01), while the change of cell proliferation is opposite to that of apoptosis, indicating that the interaction between PD-L1 and PD-1 could result in tumor immune escape and inhibit apoptosis in K7M2 cells.