On the contrary, tumor cell-intrinsic PD-1 has been reported as a tumor suppressor gene in non-small cell lung carcinoma (NSCLC) and colon cancer.21 133 A previous study reported a 61-year-old woman diagnosed with stage IV NSCLC who was unresponsive to several chemotherapies and experienced rapid disease progression after receiving radiotherapy combined with pembrolizumab.133 PD-1 and PD-L1 expression in the irradiated tumor tissue biopsies obtained prior to pembrolizumab treatment were assessed by immunohistochemistry (IHC). The gene discussed is PDCD1; the disease is malignant colon neoplasm.