TGF-β reduces colitis-associated tumorigenesis by inhibiting the IL-6/STAT3 signaling pathway7, 31, based on which, we hypothesized that the deficiency of 5-HT2B promotes the tumorigenesis of CAC through the attenuation of the inhibitory effect of TGF-β on IL-6/STAT3. This evidence concerns the gene HTR2B and colitis.