Influence of a 5-bp Indel Polymorphism at Promoter of the GAS5 lncRNA and Risk of Breast Cancer

Long non-coding RNAs (lncRNAs) are RNA molecules (>200 nucleotides in length) with no protein-coding capacity. Recent studies have demonstrated that lncRNAs involve in the regulation of their target genes at transcriptional, post-transcriptional and epigenetic levels. The aim of this case-control study was to explore whether growth arrest-specific 5 (GAS5) lncRNA 5-bp Ins/Del (rs145204276) polymorphism is involved in the breast cancer susceptibility. A total of 170 cases and 220 age matched controls were recruited in this study. GAS5 lncRNA polymorphism was genotyped using tetra primers amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) method. Statistical analysis was performed using SPSS. The distribution of the genotype ins/ins, ins/del and del/del were %75.29, 21.76% and 2.94% and 52.27%, 39.55% and 8.81% in the cases and controls, respectively. The ins/del or del/del genotype had a significantly decreased risk of breast cancer as compared with the ins/ins genotype under a codominant model (OR=0.38, 95%CI 0.24-0.60, p=0.0001; OR= 0.25, 95%CI 0.09-0.69, p=0.008, respectively). Moreover, the deletion allele of this polymorphic site is associated with a protective effect (OR=0.41, 95%CI 0.28-0.60, p=0.0001). Our study provided the first evidence that the deletion allele of GAS5 rs145204276 may have a protective role in mediating individual susceptibility to breast cancer. However, further comprehensive studies are warranted in a larger sample.