Association of prostate stem cell antigen gene polymorphisms with the risk of stomach cancer in Japanese

A recent whole-genome association study identified a strong association between polymorphisms in the prostate stem cell antigen (PSCA) gene and stomach cancer risk. In this case-control study, we aimed to validate this association, and further to explore environmental factors possibly interacting with PSCA polymorphisms in 708 incident stomach cancer cases and 708 age-sex matched controls. The association between PSCA polymorphisms and Helicobacter pylori infection was also examined. We found that rs2294008 and rs2976392, which were strongly linked to each other (D′ = 1.00), were significantly associated with stomach cancer risk. Per allele odds ratio for rs2994008 was 1.40 (95% confidence interval: 1.19-1.65; p = 3.7 × 10^-5). We found significant interaction with a family history of stomach cancer in first-degree relatives (p-heterogeneity = 0.009). Similar to originally reported association, we found significant heterogeneity between diffuse and intestinal type (p-heterogeneity = 0.007). No association was seen between PSCA polymorphisms and H. pylori infection. In conclusion, PSCA polymorphisms are associated with stomach cancer risk in Japanese. A possible interaction with family history warrants further evaluation.