Immune checkpoint proteins such as cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1)/PD-1 ligand (PD-L1) axis modulate immune responses by negatively regulating T cells (3, 4); however, this mechanism may impair anti-tumor immune responses in patients with malignancy. This evidence concerns the gene CTLA4 and neoplasm.