CTLA4 and head and neck squamous cell carcinoma: The most common target is CD20 (24%) on B cell malignancies, followed by GD2 (15%) in neuroblastoma and EGFR (15%) on several solid malignancies such as NSCLC and gastrointestinal cancers, PD-1 (11%) on biliary tract and other malignant solid tumors, HER-2 (11%) on HER-2-positive solid tumors such as breast carcinomas, CCR4 (4%) in T cell leukemias and lymphomas, CTLA-4 (4%) in HNSCC, SLAMF7 (4%) on B cell malignancies, VEGF (4%) on malignant solid tumors, PD-L1 (4%) in advanced solid tumors and CD22 (4%) in pediatric leukemias.