Mutant Kras Promotes Hyperplasia and Alters Differentiation in the Colon Epithelium but Does Not Expand the Presumptive Stem Cell Pool

Although Kras/KRAS mutation promotes serrated and hyperplastic morphologic features in colon epithelium, it is not able to initiate adenoma development, perhaps in part because activated Kras/KRAS signaling does not increase the number of presumptive stem cells in affected crypts.