Intestinal polyposis in Bmpr2-deficient mice. Hamartoma-like polypoid mass formation in duodenum (A,C,E), and cecum (B,D) of Bmpr2 KD mice. (C,D) Enlarged views of the boxed area in panels A and B, respectively. Arrow in panel A indicates disorganized epithelial glands, and arrowheads in panel C point to mitotic figures and distorted nuclear morphology. (E) Ki67 staining of adjacent serial sections. Bars = 100 μm. (F) Immunoblots of protein extracts from cecum (Ce) and colon (Co) of a Bmpr2 KD mouse and its wild-type littermate using antibodies against phosphor-AKT and total AKT.