Cancer cells may also secrete inhibitory, Th2-type cytokines including transforming growth factor β (TGF-β), interleukin 4 (IL-4) and IL-10 that in turn stimulate the recruitment, generation and propagation of tumorsupportive immune cells including Foxp3+ regulatory T (Treg) and B (Breg) cells, M2-polarized tumor associated macrophages (TAMs) and myeloid derived suppressor cells (MDSCs). This evidence concerns the gene IL4 and cancer.