RESUMO
INTRODUCTION: Genome-wide association studies have identified a genetic variant rs17356907 in netrin 4 (NTN4) as a risk locus of breast cancer (BC) in Europeans. NTN4 is a target gene of miR-17-92 cluster that is an oncogenic miRNA in BC development. We aimed to replicate the rs17356907 in a Chinese population and examine the interaction of NTN4 and miR-17-92 on BC susceptibility. MATERIALS AND METHODS: The rs17356907 in NTN4 and 3 additional polymorphisms in the promoter of miR-17-92 (ie, rs9588884, rs982873, and rs1813389) were determined in 415 patients with BC and 420 healthy controls using a TaqMan assay. The expression levels of NTN4 in BC and normal tissues were performed using the quantitative reverse transcription-PCR. RESULTS: With reference to the rs17356907AA genotype, the GG genotype was associated with a decreased risk of BC with an adjusted OR of 0.38 (95% CI: 0.20-0.74). With reference to the rs17356907AA-rs982873CT/CC genotypes, the rs17356907 AG/GG-rs982873CT/CC genotypes were associated with a borderline decreased risk of BC with an adjusted OR of 0.67 (95% CI: 0.48-0.93). Gene-gene interaction analysis showed that the rs17356907-rs982873-rs9588884-rs1813389 was the best model on BC susceptibility. Furthermore, the rs17356907GG genotype displayed higher levels of NTN4 mRNA. CONCLUSIONS: The NTN4 rs17356907 may have a single and interactive effect with miR-17-92 polymorphisms on the risk of BC.