Geno- and phenotypic characterization of the de novo arising colon carcinoma in familial polyposis coli.

De novo origin of colon carcinomas has been demonstrated in a case of familial polyposis. Independent origin of the polyps and the synchronous carcinomas was confirmed by their different pheno- and genotypes. Characterization of the phenotype was based on the mucin profile of the polyps and the synchronous carcinoma. The phenotype of each polyp was different and represented either duodenal, colonic or embryonal type of differentiation. The phenotype of carcinoma proved to be adult colonic type. The DNA content of the polyps and carcinoma has been evaluated by cytophotometry. The multiclonal origin of each polyps and synchronous carcinomas has been supported by their different DNA indices. Occurrence of de novo arising carcinoma in familial polyposis calls for a frequent follow-up examination of patients with subtotal colectomy and strongly support the need for total colectomy.