MUTATION ANALYSIS OF K-RAS ONCOGENES IN GASTROENTEROLOGIC CANCERS BY THE AMPLIFIED CREATED RESTRICTION SITES METHOD

A rapid, simple, and nonradioactive method for diagnosing point mutati ons of c-K-ras oncogenes in gastroenterologic cancers is described. Th is method involved the selective amplification of DNA fragments from c ancer tissues of surgical specimens with specific oligonucleotide prim ers, followed by digestion with restriction enzymes that recognized ar tificially created or naturally occurring restriction sites. To detect codon 12 mutations, an artificial Msp I site was created by introduci ng a single nucleotide mismatch into the 5' mutagenesis primer. Using a similar approach, an Hae III site was created to detect codon 13 mut ations. Bal I and MBo II sites were used to detect codon 61 mutations. A total of 61 gastroenterologic cancer cases were studied. Of 35 case s of colorectal cancer, 7 showed mutations: 6 at codon 12 and 1 at cod on 13. In 1 of 2 cases of cholangiocellular carcinoma, point mutation at codon 12 was found. One case of duodenal cancer showed point mutati on at codon 12. No mutations were found in the cases of hepatocellular carcinoma (4), gastric cancer (12), esophageal cancer (3), or pancrea tic cancer (2).