p53 Gene Mutations in Colorectal Tumors from Patients with Familial Polyposis Coli

The p5i gene has been elucidated as a tumor suppressor gene, and inactivation of this gene caused by deletion or point mutations may playa crucial role in the development of human malignancies. In colorectalcarcinomas with an allelic deletion of the p53 gene, the remaining pSigene was mutated with considerable frequency. It is most difficult todetect point mutations or small deletions of the gene because the mutations occur in diverse regions, although four hot spots have been observed|J. M. Nigro et al. Nature (Lond.), 342:705-708,1989|. The polymerasechain reaction and denaturing gradient gel electrophoresis facilitate detection of mutations in the hot spots of thep53 gene. Using these methods,we detected mutations in three adenomatous polyps and one carcinomafrom familial polyposis coli patients and three carcinomas of sporadiccases. The DNA sequence analysis confirmed mutations of the p53 genein 2 adenomas (13 basepair deletions in one and a point mutation in theother) and 1 carcinoma (point mutation) from familial polyposis colipatients. These results suggest that the p53 gene mutations may beinvolved in the formation not only of carcinomas but also of adenomaswhich occur in familial polyposis coli patients.