Genome-Wide Association of Genetic Variation in the PSCA Gene with Gastric Cancer Susceptibility in a Korean Population.

Purpose: Half of the world's gastric cancer cases and the highest gastric cancer mortality rates are observed in Eastern Asia. Although several genome-wide association studies (GWASs) have revealed susceptibility genes associated with gastric cancer, no GWASs have been conducted in the Korean population, which has the highest incidence of gastric cancer.

Materials and Methods: We performed genome scanning of 450 gastric cancer cases and 1,134 controls via Affymetrix Axiom Exome 319 arrays, followed by replication of 803 gastric cancer cases and 3,693 healthy controls.

Results: We showed that the rs2976394 in the prostate stem cell antigen (PSCA) gene is a gastric-cancer-susceptibility gene in a Korean population, with genome-wide significance and an odds ratio (OR) of 0.70 (95% confidence interval [CI]=0.64-0.77). A strong linkage disequilibrium with rs2294008 was also found, indicating an association with susceptibility. Individuals with the CC genotype of the PSCA gene showed an approximately 2-fold lower risk of gastric cancer compared to those with the TT genotype (OR=0.47; 95% CI=0.39-0.57). The effect of the PSCA gene on gastric cancer was more prominent in the female population and for diffuse type gastric cancer.

Conclusion: Our result confirmed that the PSCA gene may be the most important susceptibility gene for gastric cancer risk in a Korean population.