CD4 and neoplasm: In addition to MHC-II antigen presentation serving as a chemotaxic signal for CD4+ T cells, evidence suggests that tumor cells may recruit CD4+ T cells through cytokines IL-10 and TGF-β: specifically, IL-17 expression in mouse colorectal tumors limited the expression of these cytokines, decreasing CD4+ T cell infiltration94 [Fig. 2(a)].