A total of 5 tagging single-nucleotide polymorphisms (rs2299941 of PTEN, rs2735385, rs6999227, rs1805812, and rs1061302 of Nijmegen breakage syndrome 1) were tightly associated with breast cancer risk in sporadic cases, and 5 other tagging single-nucleotide polymorphisms (rs1042522 of TP53, rs2735343 of PTEN, rs7220719, rs16945628, and rs11871753 of BRCA1-interacting protein 1) were tightly associated with breast cancer risk in familial and early-onset cases.
Four haplotypes within two genes (NBS1 and BRIP1) involved in the monoubiquitinated FANCD2-DNA damage-repair pathway are significantly associated with increased sporadic breast cancer risk, while one haplotype within NBS1 is correlated with an increased risk of familial or early-onset breast cancer, indicating that specific haplotypes may be distinct predictors of breast cancer.
On the basis of the fact that BRIP1/FANCJ interacts with BRCA1 and functions as a regulator of DNA double-strand break repair pathways, and that germline mutations within the BRIP1/FANCJ gene predispose to breast cancer, we chose this gene as a candidate for mutation screening in familial and young-onset PrCa cases.