IL17A and colorectal carcinoma: Mechanistically, Singh et al. found that butyrate-mediated activation of GPR109A could upregulate anti-inflammatory effector molecules IL-10 and Aldh1a in colonic DCs and macrophages, which promoted the differentiation of IL-10-producing CD4 T cells and Tregs, and inhibited the development of IL17-producing T cells, thereby inhibiting the occurrence of CRC [50].