Treg cells in human colon tumor tissues express immunosuppressive molecules such as PD-1, cytotoxic T-lymphocyte-associated protein-4 (CTLA-4), T cell immunoglobulin and mucin domain-3 (TIM-3) and lymphocyte-activation gene 3 (LAG-3) [209]. This evidence concerns the gene CTLA4 and colonic neoplasm.