It has been shown (57) that 90% of MSI CRC are attributed to abnormal TGF-β signaling pathway, so it can be speculated that TGF-βR II and ACVR mutations in the TGF-β pathway have a synergistic effect on MSI CRC, which further clarifies the mechanism of MSI colorectal carcinogenesis and adds more solution for challenges of the MSI CRC clinical therapeutic selection of drugs. This evidence concerns the gene TGFB1 and medical procedure.