mircoRNAs (
miRNAs) play important roles on regulation of gene expressions. Aberrant expression of
miRNAs was involved in various biological and
pathological processes, including
tumorigenesis of
breast cancer. Single-nucleotide polymorphisms (SNPs) were implicated in altered expression or biological functions of mature
miRNAs. To explore the relevance of
miRNA polymorphisms and female physiological characteristics to
breast cancer risk, SNPs located within
hsa-miR-605 (rs2043556),
hsa-miR-149 (rs2292832), hsa-miR-27a (rs895819), hsa-miR-196a-2 (rs11614913) and
hsa-miR-618 (rs2682818) were selected, and their associations with
breast cancer risk were analysed. In addition, associations between physiological characteristics-related factors and
breast cancer risk were estimated too. We found that the ones with menarche age less than 16 years had increased
breast cancer risk (OR = 2.10, 95% CI: 1.23-3.60). Marginally significant association between rs11614913 CT/CC genotypes and reduced
breast cancer risk was observed (OR = 0.65, 95% CI: 0.40-1.06), while no significance was detected about the other
miRNA polymorphisms. We concluded that menarche at less than 16 years old increased
breast cancer risk, while the genetic variants in miR-196-a-2 might decrease the risk.