Immunosuppressive cells such as tumour-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs), CD4 positive regulatory T cells (Tregs), and stromal cells through the combinatorial action of cell surface and secreted molecules such as immunoregulatory cytokines, chemokines, and prostaglandins can block T-cell infiltration and activation and can directly inhibit cytotoxic T-cells from attacking cancer cells. This evidence concerns the gene CD4 and neoplasm.