In cancer, some immune cells are known to induce anti-tumoural effects (natural killer cells, CD8+ T cells, Th1 cells, dendritic cells 1, M1 macrophages, and so forth), and others induce pro-tumoural effects (myeloid-derived suppressor cells, CD4+ T cells, Th2 cells, dendritic cells 2, M2 macrophages, and so forth) [33,34]. This evidence concerns the gene CD4 and cancer.