Clinical significance of papillary thyroid cancer risk loci identified by genome-wide association studies

Four single nucleotide polymorphisms (SNPs) have been reported to be associated with thyroid cancer risk in two genome-wide association studies (GWASs) and were validated in a Chinese population. Because of a lack of further clinical and functional evidence, the clinical significances of these SNPs remain unknown. Four GWAS-identified SNPs of papillary thyroid cancer (PTC), rs965513, rs944289, rs966423 and rs2439302, were genotyped in a case-control study of 838 patients with PTC and 501 patients with benign thyroid tumor (BTT) from the Chinese Han population. The associations between these SNPs, clinicopathologic features, and the outcome of the PTC patients were examined. The CT and CT + TT genotypes of rs966423 were more common in PTC patients with extrathyroidal extension and more advanced T stage. The TC and TC + CC genotypes and the C allele of rs944289 were significantly less frequent in patients with multifocal disease. No correlation was observed between GWAS-identified SNPs and disease persistence of PTC after a short-term follow-up. Significantly different allele distributions between the PTC and BTT groups were observed for all four selected SNPs. Individuals with more than five risk alleles were 8.84-fold (95% CI 3.23-24.17) more likely to suffer from PTC compared with those with zero or 1 risk allele. GWAS-identified SNPs affect the individual predisposition to PTC without interacting with existing Hashimoto thyroiditis and BTT lesions. GWAS-identified SNPs were associated with certain clinicopathologic features of PTC, and may contribute to identifying PTC patients with different clinical patterns. Large prospective studies are required to further evaluate the diagnostic and prognostic power of these genetic markers.