In this study, we performed a large population-based case-control study on breast cancer in China with the purpose of investigating the relationship between RASA2 (rs16851483), CADM1 (rs12286929), HIF1AN (rs17094222) polymorphisms, as well as their joint effects with body fatness and the occurrence of breast cancer among Chinese women. The gene discussed is HIF1AN; the disease is breast cancer.