p53 genetic polymorphism of gastric cancer in Korea

Background: Deletion or functional loss of the p53 tumor suppression gene plays a role in oncogenic transformation. The codon 72 polymorphism on exon 4 in the p53 gene produces variant proteins with either arginine (Arg) or proline (Pro), and is associated with an increased susceptibility of cancers of the lung, esophagus, breast, cervix and nasopharynx on a genetic basis. We designed this study to evaluate the influence of the p53 codon 72 polymorphism on gastric cancer in Korea. Methods: We extracted the peripheral blood samples in 84 patients with gastric cancer, 66 patients with H. pylori-associated chronic gastritis and 43 controls without H. pylori infection. PCR-RFLP analysis was performed to detect p53 codon 72 polymorphism in these patients. Results: There was no specific genotype of p53 polymorphism in the gastric cancer group compared to the other groups and no difference in genotypes by histologic subtypes. Classified by tumor location, Pro/Pro genotype was associated with an increase in proximal cancer and Arg/Arg genotype with distal cancer. As the frequency of p53 Arg allele increased, the cancer was of a more poorly differentiated type. Conclusions: The specific genotype of p53 polymorphism seems to correlate with tumor location. Increased frequency of p53 Arg allele is associated with more poorly differentiated cancers.