MRC1 and colorectal cancer: Moreover, the expected incidence was fourfold higher than in the general population.[20] Similarly, the risk of colon cancer was relatively higher in patients with small intestinal cancer.[20] A possible explanation is that both small intestinal cancer and colorectal cancer are associated mutations of KRAS, P53, and MMR genes.[20,21] However, in a population-based study in Denmark, Bojesen et al[22] found no evidence of microsatellite instability in the 23 patients with Crohn disease who developed small bowel adenocarcinoma.