Association Between Genetic Polymorphisms in the Promoter Regions of Let-7 and Risk of Papillary Thyroid Carcinoma: A Case-Control Study

The aim of this study was to investigate the association between 2 polymorphisms (ie, rs10877887 and rs13293512) in the promoter regions of let-7 and the risk of papillary thyroid carcinoma (PTC). A case-control study of 618 PTC patients and 562 controls was conducted. The rs10877887 polymorphism was genotyped by using polymerase chain reaction-restriction fragment length polymorphism and the rs13293512 polymorphism was genotyped by using a TaqMan Genotyping Assay. The results were confirmed by DNA sequencing. The rs10877887 polymorphism had reduced risks of PTC in heterozygous comparison, dominant model, and overdominant model (TC vs TT: adjusted odds ratio [OR] = 0.73, 95% confidence interval [95% CI] = 0.58–0.94, P = 0.01; TC/CC vs TT: adjusted OR = 0.79, 95% CI = 0.63–1.00, P = 0.047; TC vs TT/CC: adjusted OR = 0.73, 95% CI = 0.57–0.92, P = 0.007, respectively). Stratified analyses showed that PTC patients carrying the rs10877887 CC genotype were more likely to have multiple tumors (adjusted OR = 1.71, 95% CI = 1.03–2.86, P = 0.04), and PTC patients carrying the rs13293512 TC + CC or CC were more likely to develop N0 status (TC/CC vs TT: adjusted OR = 0.64, 95% CI = 0.43–0.94, P = 0.02; CC vs TC/TT: adjusted OR = 0.50, 95% CI = 0.33–0.77, P = 0.001, respectively). Our study suggests that the rs10877887 polymorphism may be associated with the risk of PTC and the rs13293512 polymorphism may correlate to lymph node metastasis in PTC.