CD4 and colorectal carcinoma: Meanwhile, regulatory T cells (CD4+FOXP3+; Tregs) were thought to have a tumor-promoting function in CRC,28 IL-37 has been found to induce Tregs in skin contact hypersensitivity model and atherosclerotic model.29 However, Treg cells were present in the colons of both AOM/DSS-treated IL-37tg and WT mice with no significance (Fig. 3b).