A previous study has also shown an association between T2DM and a higher risk of CRC for patients with the risk allele of TCF7L2 rs7903146, and several of them have shown an independent association with T2DM and CRC, suggesting that the risk allele is likely to have a more important effect on colon tissue than in the pancreatic islet [8,27,28]. Here, TCF7L2 is linked to type 2 diabetes mellitus.