Molecular evidence for multicentric development of thyroid carcinomas in patients with familial adenomatous polyposis

Familial adenomatous polyposis is characterized by multiple colorectal aden omas and an increased incidence of colorectal carcinomas. Patients also dev elop various extracolonic tumors, of which, thyroid carcinoma is common in young females. The occurrence of multiple carcinomas in one thyroid is freq uently observed, although some carcinomas are solitary. To clarify whether each carcinoma develops independently or metastatically spreads from the fi rst one formed, we analyzed the adenomatous polyposis coil (APC) gene mutat ion in each carcinoma, We found that each carcinoma had a different somatic mutation of the APC gene. This is molecular confirmation for the multicent ric development of thyroid carcinomas in familial adenomatous polyposis thr ough biallelic inactivation of the APC gene.