CD4 and neoplasm: T lymphocytes are mainly divided into different functional subsets: helper (CD3+CD4+) T cells, killer (CD3+CD8+) T cells, regulatory T (Treg) cells, etc. CD8+T cells are the main antitumor effector cells, and CD4+T cells promote their activation and proliferation and the two synergistic antitumor, while Treg cells can induce tumor immunosuppression and immune escape [5].