Background: Research into the etiology of breast cancer has recently focused on the role of the immunity and inflammation. Interleukin-23 and its receptor (IL23R) guide T cells towards the Th17 phenotype. IL23R single nucleotide polymorphisms (SNPs) have been shown to be associated with digestive system cancers. To evaluate the influences of IL23R gene polymorphisms on the risk of sporadic breast cancer, a case-control study was conducted in Chinese Han women.
Methodology and principal findings: We genotyped two tag SNPs (rs10889677 in the 3'-UTR region and nonsynonymous variants rs1884444 in exon 2) in IL23R gene of 491 breast cancer patients and 502 matched healthy controls. The genotypes were determined using the SNaPshot technique. The differences in the genotypic distribution between breast cancer patients and healthy controls were analyzed with the Chi-square test for trends. For rs10889677 in IL23R, the frequencies of the AA genotype and the A allele were statistical significant higher in breast cancer patients than in controls (P = 0.0084 and P = 0.0171, respectively), whereas the C allele was associated with an earlier age of breast cancer onset (50.6 years for AA, 48.7 years for AC and 46.0 years for CC (P = 0.0114)) in case-only study. The clinical features analysis demonstrated significant associations between rs1884444 in IL23R and human epidermal growth factor receptor 2 (Her-2) and tumor size status.
Conclusions and significance: Our results suggest that a miRNA binding site SNP in the 3'-UTR region of the IL23R gene may be associated with the risk of breast cancer and contribute to the early development of breast cancer in Chinese women.