ABO blood groups and expression of blood group antigens of epithelial ovarian cancer in Chinese women

Background: ： The association of ABO blood groups with epithelial ovarian cancer (EOC) risk has been reported. However, the results are inconsistent and little is known about the alterations of histo-blood group antigens expression and ABO gene expression in ovarian tumor tissues. Methods: ： We used two single nucleotide polymorphisms in ABO gene (rs8176719 and rs8176746) to determine ABO blood group of 1,870 EOC cases and 4,829 controls. Expression of A and B antigen in 70 ovarian tumor tissues and adjacent normal tissues were detected by immunohistochemistry. Gene expression and DNA methylation profiling was detected in ovarian tumor tissues. Results: ： In this case-control study, blood group A was associated with increased risk for EOC compared with blood group O ( OR = 1.18, 95 % CI = 1.03 – 1.36, P = 0.019), this association remained significant after multivariate adjustment (adjusted OR  = 1.48, 95% CI = 1.11 – 1.96, P = 0.007). Patients with blood group A had higher rate of aberrant histo-blood group antigen expression compared to patients with blood group O and B (76.5% vs. 21.1%, 5.0%, P <0.001). ABO gene expression was down-regulated in ovarian tumor tissues compared with paired adjacent normal tissues ( P = 0.027). NFYB was positively correlated with ABO gene expression ( r = 0.38, P <0.001) and DNA methylation level of four CpG sites was significantly inversely correlated with ABO gene expression (cg11879188, r = - 0.3, P = 0.002; cg22535403, r = - 0.30, P = 0.002; cg13506600, r = - 0.22, P = 0.025; cg07241568, r = - 0.21, P = 0.049). Conclusions: ： We identified blood group A was associated with increased EOC risk in Chinese women and provided the clues of the possible molecular mechanisms of blood group A related to ovarian cancer risk. Functional studies are warrant to clarify the role of A antigen and ABO gene in ovarian cancer carcinogenesis.