Association of a Pre-miR-27a Polymorphism with Cancer Risk: an Updated Meta-analysis


MicroRNA-27a is highly expressed in cancers and has been identified as an oncogenic microRNA. A geneticvariant in pre-miR-27a (rs895819) with a transition of A to G has been demonstrated to be associated with cancerrisk; however, the results of these studies remain conflicting rather than conclusive. Therefore, we performed ameta-analysis to derive a more precise estimation. Through searching PubMed or other databases up to March2014 using the following MeSH terms and keywords, “miR-27a”, “polymorphism” and “cancer”, seventeencase-control studies were identified in this meta-analysis, including 7,813 cases and 9,602. Crude odds ratios(ORs) and corresponding 95% confidence intervals (CIs) were calculated to investigate the association strengthbetween rs895819 and the susceptibility of cancer. The results of the overall meta-analysis did not suggest anyassociation between rs895819 polymorphism and cancer susceptibility, and this remained in Asians as a subgroup.In Caucasians, however, the rs895819 was associated with a reduced cancer risk in heterozygous (OR,0.83; 95%CI, 0.75-0.93) and dominant models (OR, 0.84; 95%CI, 0.76-0.93), and the [G] allele of rs895819showed a protective effect (OR, 0.90, 95%CI, 0.84-0.97). Further studies showed a significant association betweenthe [G] allele of rs895819 and decreased risk of breast cancer (0.91; 95%CI, 0.85-0.98), and stratified analysesindicated a protective effect of the [G] allele in Caucasians (OR, 0.89; 95%CI, 0.82-0.98), younger breast cancercases (OR, 0.87; 95%CI, 0.79-0.96), and in the group of unilateral breast cancer patients (OR, 0.90; 95%CI,0.83-0.97). These findings suggest an association between pre-miR-27a polymorphism rs895819 and cancer riskin Caucasians. The protective effect of rs895819 [G] allele in younger breast cancer and in the group of unilateralbreast cancer patients await further confirmation since the included studies in this meta-analysis were limited.