Polymorphisms in BRCA1, BRCA1-interacting genes and susceptibility of breast cancer in Chinese women

BRCA1-interacting protein C-terminal helicase 1 (BRIP1) and zinc finger protein 350 (ZNF350) work with BRCA1 in tumor suppression procedures. Low penetrance variants of these three genes may jointly affect individuals' breast cancer susceptibility in general population. We focused on potentially functional single nucleotide polymorphisms (SNPs) in the coding regions of BRIP1, ZNF350 and BRCA1 and pairwise-tagging approach was used to minimize the number of SNPs. Five SNPs were selected and genotyped by PCR-restriction fraction length polymorphism or PCR-primer introduced restriction analysis assays in a case-control study with 568 breast cancer cases and 624 controls in a Chinese population. All of the five SNPs except rs2278415 of ZNF350 conferred a modestly increased risk, although, with no statistical significance. Joint effect analyses indicated that all the variant genotypes of ZNF350 polymorphisms accounted for increased breast cancer risk among subjects carrying variant homozygote of BRCA1 rs799917, particularly for ZNF350 rs4986773 (OR = 2.03, 95%CI = 1.02-4.05, the test for gene-gene interaction P (int) = 0.059). BRCA1 and ZNF350 may jointly contribute to individuals' susceptibility of breast cancer in Chinese women. Further functional studies are warranted to validate our findings.