The apoptosis of T lymphocytes induced by tumor cells [5], decreased tumor-infiltrative lymphocytes due to programmed death-ligand 1 expressed on surfaces of antigen-presenting or tumor cells, and the suppression of immune cells such as T-helper CD4+ T or CD8+ T cells via recruiting regulatory CD4+ T cells can result from tumors [6,7]. This evidence concerns the gene CD4 and neoplasm.