When FFAR2 is deleted, dendritic cells become overactivated and produce IL‐27 which further impairs immunocompetence against colorectal tumors by depleting CD8+ T cells.[42] Colonic SCFAs also inhibit the secretion of the pro‐inflammatory cytokine IL‐8 by the epithelial cells to suppress colon cancer, but whether this function is receptor‐independent or ‐dependent needs to be further investigated.[43] For example, n‐butyrate down‐regulates the expression of IL‐6 and IL‐12 as well as the level of nitric oxide (NO) in macrophages independent of G protein‐coupled receptors. This evidence concerns the gene CXCL8 and colonic neoplasm.