USING BIOPSY MATERIALS TO DETECT MUTATIONS IN GASTROINTESTINAL TUMORS

Because endoscopic examinations are a crucial first step in the diagno sis of carcinomas, we have analyzed point mutations of the c-K-ras and p53 genes using biopsied samples. There is no previous report of such an approach, using only biopsied materials. We analyzed point mutatio ns of the c-K-ras and p53 genes using 60 colorectal and 31 gastric tum or biopsy specimens. None of the gastric and seven of the colorectal t umors had mutations of the c-K-ras gene. p53 gene mutations were detec ted in six gastric carcinomas [two out of 11 intramucosal carcinomas ( 18.2%) and four out of 11 invasive carcinomas (36.4%)]. Eight of 15 in vasive colorectal carcinomas (53.3%) showed point mutations in the p53 gene. Although point mutation frequencies in this study were relative ly low when compared with previous reports in which surgical samples w ere used, our study shows that biopsied specimens are adequate and use ful for analysis of gene point mutations.