Cancers have the ability to increase the abundance of immunosuppressive cells (Treg cells and tumor-associated macrophages) and the expression of immunosuppressive molecules (cytotoxic T lymphocyte-associated antigen 4, CTLA-4), and reduce the expression of tumor antigens, resulting in CD8+ T cells being unable to identify cancer cells (Zou and chen, 2008; Pardoll 2012). This evidence concerns the gene CTLA4 and cancer.