Endocrine Abstracts

Background: Thyroid carcinomas are the most frequent endocrine malignancies of which more than nighty percent are differentiated thyroid carcinomas (DTC). It’s known that genetic variation plays 75% role in the development of papillary thyroid carcinoma (PTC).

Material and methods: In a case control setting subjects between January 2005 and December 2015 were evaluated for inclusion in the study. We aimed to compare the genotype frequency distributions of three common X-ray repair cross-complementing group 1 (XRCC1) SNPs in those with differentiated thyroid carcinoma (n: 228) and cancer-free patirents with benign nodular goiter (n:100) and the healthy controls (n:98) with regard to some predefined risk factors like existence of Hashimoto’s thyroiditis, smoking, obesity, family history of thyroid cancer, and radiation exposure. In the present study we tried to assess the genotype frequency distributions of three common XRCC1 SNPs. Genomic DNA was extracted from peripheral lymphocytes using phenol–chloro form extraction. XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphisms were detected by amplification with real-time PCR followed by melting-curve analysis with fluorescence-labeled hybridisation probes in a LightCycler.

Results: Heterozygous GA/GG genotype frequency of the Arg280His polymorphism in DTC cases was significantly higher than in those with benign nodular goiter and in those in the healthy control group (64.5 and 3%, respectively; P<0.001). The frequency of homozygous AA genotype of Arg280His polymorphism was lowest in the DTC group (35.5%). The difference was statistically significant (P<0.001). Presence of family history of thyroid cancer was 7.9% in DTC group and 1% in benign nodular group. The difference was statistically significant (P=0.014).

Discussion: In conclusion, our study demonstrates that Arg280His GA/GG genotype of XRCC1 gene polymorphism is more frequently encountered in DTC than in cancer-free controls. GA genotype frequency is highest in those DTC cases with a family history of thyroid cancer.