Thyroid Cancer: The Quest for Genetic Susceptibility Involving DNA Repair Genes

• Main Authors: Luís S. Santos, Bruno Costa Gomes, Hélder N. Bastos, Octávia M. Gil, Ana Paula Azevedo, Teresa C. Ferreira, Edward Limbert, Susana N. Silva, José Rueff
• Format: Article
• Language: English
• Published: MDPI AG 2019-08-01
• Series: Genes
• Subjects: Thyroid cancer; DNA repair; genetic susceptibility; genetic markers; SNPs
• Online Access: https://www.mdpi.com/2073-4425/10/8/586

The incidence of thyroid cancer (TC), particularly well-differentiated forms (DTC), has been rising and remains the highest among endocrine malignancies. Although ionizing radiation (IR) is well established on DTC aetiology, other environmental and genetic factors may also be involved. DNA repair single nucleotide polymorphisms (SNPs) could be among the former, helping in explaining the high incidence. To further clarify the role of DNA repair SNPs in DTC susceptibility, we analyzed 36 SNPs in 27 DNA repair genes in a population of 106 DTCs and corresponding controls with the aim of interpreting joint data from previously studied isolated SNPs in DNA repair genes. Significant associations with DTC susceptibility were observed for <i>XRCC3</i> rs861539, <i>XPC</i> rs2228001, <i>CCNH</i> rs2230641, <i>MSH6</i> rs1042821 and <i>ERCC5</i> rs2227869 and for a haplotype block on chromosome 5q. From 595 SNP-SNP combinations tested and 114 showing relevance, 15 significant SNP combinations (<i>p</i> &lt; 0.01) were detected on paired SNP analysis, most of which involving <i>CCNH</i> rs2230641 and mismatch repair variants. Overall, a gene-dosage effect between the number of risk genotypes and DTC predisposition was observed. In spite of the volume of data presented, new studies are sought to provide an interpretability of the role of SNPs in DNA repair genes and their combinations in DTC susceptibility.