CD4 and malignant colon neoplasm: Memory CD4+ T cells are well characterized as having lower activation thresholds, an enhanced capacity to migrate to lymph nodes, long survival times, and reduced susceptibility to suppression by Treg cells and are the primary immune surveillance cells of the colon mucosa; thus, memory CD4+ T cells, rather than effector T cells, have become the focus of immunotherapy for colon cancer (26).