Which of the following statements is not true about inhereted susceptibility to colon cancer?

D. None of the above.

DISCUSSION: In addition to familial polyposis syndrome, hereditary nonpolyposis colorectal cancer (HNPCC) includes site-specific colorectal cancer and cancer family syndrome, which are synonymous with Lynch syndromes I and II, respectively. Autosomal-dominant inheritance of colorectal cancer is observed in both syndromes, and the average patient age at cancer diagnosis is 45 years. Persons with HNPCC have a high occurrence of synchronous and proximal colon malignancies. Affected persons usually exhibit one or several adenomatous polyps. The polyps on average are larger, have more villous histology, and occur at a younger age than adenomas in the general population. Cancer family syndrome also includes other malignancies, especially endometrial lesions but also ovarian, gastric, small intestinal, and renal cancer.