APC and Familial adenomatous polyposis: Differences in tumor progression to adenocarcinoma as well as the incidence of extracolonic lesions in Apcmin/+Vdr−/− animals compared to those of Apc1638N/+Vdr−/− animals mouse model strongly suggest that the location of mutation in the APC gene (genotype) and VDR may closely relate to phenotypic changes such as polyp formation and extracolonic lesions in FAP patients, particularly in the context of VDR loss or inactivation.