Loading...
About 15% of sporadic colorectal cancers exhibit high-frequency microsatellite instability (MSI-H) and inactivation of hMLH1 (a mismatch repair gene). In previous retrospective studies, similar molecular changes have been seen in hyperplastic polyps and sessile serrated adenomas in the proximal colon, leading to the theory that these lesions are precursors of sporadic MSI-H cancers in the proximal colon.
In a new prospective colonoscopy study, investigators sought to determine the prevalence of serrated polyps, including hyperplastic polyps and serrated adenomas, and to describe the prevalence of BRAF and K-ras mutations in such polyps. BRAF and K-ras are involved in the same signaling pathway, and mutations in these genes are mutually exclu…