Evaluation of common genetic risk factors for differentiated thyroid cancer in the Thai population.

Differentiated thyroid carcinoma (DTC) is the most common endocrine malignancy. This disease includes papillary and follicular thyroid tumors, and accounts for the majority of thyroid cancer cases. Although both genetic and environmental variables contribute to the genesis of DTC, specific genetic variants in the Thai population remain to be fully understood. The present case-control study aimed to investigate six single nucleotide polymorphisms (SNPs) associated with DTC susceptibility that had previously been described in genome-wide association studies; namely, rs944289, rs2439302, rs966423, rs116909374, rs1799782 and rs861539, and assess these within a Thai population. A total of 233 patients with histologically confirmed DTC (84.1% papillary, 12.9% follicular, 2.6% mixed and 0.4% Hürthle cell) and 176 control subjects with no history of thyroid disease were enrolled in the present study. Polymerase chain reaction-restriction fragment length polymorphism was used for genotyping. The results of the present study revealed that the six SNPs were not statistically significant (P<0.05) in the Thai population. Moreover, results of the sex-stratified analysis demonstrated that statistically significant associations were apparent between three SNPs in males; namely, SNPs rs2439302 (CC vs. CG genotype: OR, 3.325; P=0.024), rs966423 (CC vs. CT genotype: OR, 0.263; P=0.024; C vs. T allele: OR, 3.780; P=0.015) and rs1799782 (CC vs. CT genotype: OR, 0.194; P=0.046). Collectively, results of the present study may provide useful insights into the genetic diversity associated with cancer risk within the Thai population and highlight the requirement for sex stratification in genetic investigations of thyroid cancer.