Background: Single nucleotide polymorphisms (SNPs) in the promoter region of miRNAs may disturb miRNAs processing, alter their expression, and ultimately affect an individual’s susceptibility to cancer. We conducted a case-control study to evaluate the association of rs353293 G>A with the risk of thyroid cancer in the Iranian population.
Methods: 192 patients with thyroid cancer including (papillary, follicular, medullary, and undifferentiated) and 125 healthy subjects were enrolled in this case-control study. rs353293 G>A polymorphism in the promoter region of miR-143/145 were analyzed using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP) to find the association of this SNP with thyroid cancer. Logistic regression analyses were conducted to evaluate adjusted odds ratios (ORs) for the potential confounding factors (age and sex), and 95% confidence intervals (95% CIs) between patients with thyroid cancer and controls.
Results: We found no association between rs353293 G>A polymorphism and thyroid cancer. 
Conclusion: This study suggests that the functional polymorphism in rs353293 is not associated with development of thyroid cancer. Future investigations with larger sample size should be performed to confirm our observations.