Background: Genetic factors are important in thyroid cancer susceptibility. Recently, it has been reported that there are associations of certain chromosome regions with thyroid cancer. In this case-control study, we sought to determine whether there is an association between differentiated thyroid cancer (DTC) and variants in regions of chromosome 8q.
Methods: We used a case-control association design in a population of 877 individuals (398 patients with sporadic DTC and 479 healthy controls). The iPLEX technology was applied to analyze seven single-nucleotide polymorphisms (SNPs) in chromosome 8q: two SNPs that map at 8q24, previously reported as risk markers in different types of cancer, two SNPs in the thyrotropin-releasing hormone receptor gene (TRHR), and three SNPs in the thyroglobulin gene (TG). Risk assessment was done by unconditional regression analysis.
Results: The two SNPs that map at 8q24, rs6983267 and rs1447295, and the two TRHR polymorphisms showed no association with DTC. No association was also found for the exon 33 TG polymorphism. The two TG polymorphisms in the exon 10-12 cluster, however, were associated with an increased risk of DTC (dominant model odds ratio = 1.80, 95% confidence interval = 1.30-2.50, p < 0.001).
Conclusions: In this study, we show for the first time that the TG gene is a susceptibility factor for thyroid cancer. Although these conclusions are based on a large population, additional studies are warranted to support these data.