Common genetic polymorphisms in pre-microRNAs and risk of bladder cancer

Background: At present, inconsistent association between single nucleotide polymorphism (SNP) in pre-miRNAs (hsa-mir-196a2 rs11614913 C/T, hsa-mir-499 rs3746444 A/G, and hsa-mir-146a rs2910164 C/G) and bladder cancer were obtained in limited studies. We performed a case-control study to test whether these three common polymorphisms are associated with bladder cancer. One hundred fifty-nine patients affected by bladder cancer and 298 unrelated healthy subjects were enrolled in the study. Methods: Using polymerase chain reaction-restriction fragment length polymorphism assay (PCR-RFLP), genotypes of these three SNPs were determined, and their associations with bladder cancer, as well as with clinic pathological factors, and tumor progression were analyzed. Results: No association between bladder cancer risk and variant allele of hsa-mir-196a2 rs11614913 C/T, hsa-mir-499 rs3746444 A/G, or hsa-mir-146a rs2910164 C/G was observed. Heterozygous genotype (CT genotype) of rs11614913 was associated with a significantly decreased bladder cancer risk (P = 0.004, OR = 0.56, 95 % CI = 0.38-0.83). Further stratified analyses showed that rs2910164 is associated with the tumor stage in a recessive model and with metastasis in a dominant model (P = 0.012, OR = 0.20, 95 % CI = 0.05-0.72 and P = 0.04, OR = 2.63, 95 % CI = 1.03-6.67, respectively). No association between hsa-mir-499 rs3746444 A/G and bladder cancer was observed. Conclusions: Our results suggested hsa-mir-196a2 rs11614913 C/T is associated with a significantly decreased risk of bladder cancer and hsa-mir-146a rs2910164 GG genotype is associated with clinical stage and metastasis in bladder cancer.