Which of the following is/are true about colorectal polyps?

A. Familial juvenile polyposis is associated with an increased incidence of colon cancer.

D. Endoscopic polypectomy results in a decreased incidence of carcinomas of the colon and rectum.

DISCUSSION: Juvenile polyps are hamartomas, and can cause symptoms in children such as bleeding, obstruction, and intussusception. Familial juvenile polyposis is associated with increased risk of colon carcinoma. Polyps with mixed tubular and villous appearance (tubulovillous adenomas) have an intermediate risk of malignancy; villous adenomas are the most likely to contain malignancy in each size range. While p53 and other tumor suppressor genes may be associated with the adenoma-to-carcinoma transition, it appears likely that multiple genetic defects are involved in this transformation. Alterations in p53 appear to be among the last, as changes are uncommon in adenomas but very common in carcinomas. The National Polyp Study Group (USA) demonstrated that colonoscopic polypectomy does in fact reduce the incidence of subsequent colorectal carcinomas, which supports the concept that most carcinomas begin as polyps and supports aggressive endoscopic removal.