RESUMO
Recently the adenomaatous polyposis coli(APC) gene, a tumor suppressor gene, was identified and the cDNA was cloned from chromosome 5q21. Allelic deletion or point mutation of tumor suppressor genes(TSGs) has been considered as an important mechanism in development of human tumor. Point mutations affecting APC gene are seen in the hereditary syndrome, adenomatous polyposis and spordic colon cancer. However, the mutation of APC gene and other TSGs have not been described in gastric cancer. In order to identify the mutation of exon 11 of APC gene for gastric cancer, we amplified DNA extracted from paraffin-embedded tissues by polymerase chain reaction(PCR) and digested the PCR products with restriction enzyme Rsa I. We examined the DNA extracted from paraffin-embedded 44 gastric cancer tissues with lymph nodes. Eighteen(41%) among 44 were informative for the study exon 11 of the APC gene, and we found loss of heterozygosity(LOH) for APC in 6/18(33.3%). These data suggest that the point mutation or the base change of APC gene commonly occurs in gastric cancer. We conclude that the mutation of APC gene is strongly connected with development of human gastric cancer.