The serrated pathway to colorectal carcinoma: current concepts and challenges

Approximately 30% of colorectal carcinomas develop via a serrated neoplasia pathway, named for the pattern of crypts in the precursor polyps. Molecular abnormalities consistently involve methylation of C p G islands [ C p G island methylator phenotype ( CIMP )] of low degree ( CIMP ‐ L ) or high degree ( CIMP ‐ H ), and activating mutations of the mitogen‐activated protein kinase pathway components BRAF or KRAS . Microsatellite instability ( MSI...