Clinicopathological Significance of BRAF (V600E), NRAS (Q61K) and TERT (C228T, C250T and SNP Rs2853669) Mutations in Bulgarian Papillary Thyroid Carcinoma Patients

Abstract

Abstract Introduction: Thyroid carcinoma is the most common endocrine cancer. Some somatic mutations in genes (BRAF, NRAS and TERT) involved in key signaling pathways and genome stability have been recently identified to play an important role in its development. Very little research has been done on their frequency and clinical relevance in Bulgarian patients with papillary thyroid cancer (PTC). This study is focused on investigating somatic mutation frequency in Bulgarian patients with PTC and their association with clinicopathologic features. Material and Methods: The study included 50 PTC from Bulgarian patients analyzed for mutations in BRAF (V600E), NRAS (Q61K), single nucleotide polymorphism (SNP) rs2853669 and TERT (C228T and C250T) genes by Sanger sequencing. The results were interpreted using Benchling and SeqScape software, and statistical analysis performed with SPSS. Results: In the studied PTC group BRAF(V600E) and TERT (C228T) mutations were found with frequency of 24% and 2%, respectively. Co-occurrence of both mutations was found in 1 patient (2%). The mutations Q61K (NRAS), and C250T (TERT) were not detected. The SNP rs2853669 was found in 18 patients (52.9%). Correlation analysis with the clinical characteristics of the patients revealed statistically significant association with larger size of the tumor for BRAF(V600E) and smaller tumor size for rs2853669. Conclusion: In the present pilot study, we found that BRAF(V600E) and rs2853669 in TERT are common among PCT patients. While the presence of BRAF V600E mutation was associated with large tumors, the presence of rs2853669 in TERT was found in the majority of PCT below 2 cm. More extensive molecular genetic analysis of TERT, BRAF or RAS mutations in larger sample is needed to further elucidate the clinically important diagnostic and prognostic biomarkers for thyroid cancer.