CTLA4 and head and neck cancer: The subjects were 1086 patients (818 males and 268 females, with a median age of 70 (21–91) years: 355 with lung cancer, 283 with urethral cancer, 157 with head and neck cancer, 92 with malignant melanoma, 93 with gastrointestinal cancer, 59 with hepatocellular cancer, and 46 with others; 748 treated with anti-programmed death receptor-1 (PD-1) antibody, 253 treated with anti-programmed cell death ligand-1 (PDL-1) antibody, 13 treated with anti-cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) antibody, and 72 treated via combination therapy).