The objective of the study was to investigate the role of genes (HSD3B1, CYP17A1, CYP19A1, HSD17B2, HSD17B1) involved in the steroid hormone biosynthesis pathway and progesterone receptor (PGR) in the etiology of gastric cancer in a population-based two-phase genetic association study. The gene discussed is HSD17B2; the disease is gastric cancer.