Low Prevalence of TERT Promoter, BRAF and RAS Mutations in Papillary Thyroid Cancer in the Greek Population

Thyroid cancer is a common endocrine malignancy and displays a variety of histological patterns ranging from adenoma to malignant tumors. Molecular diagnostics have given significant insights into the genetic basis of thyroid tumorigenesis, known to be linked with signaling pathways affected by oxidative stress. We report for the first time a genotype study of TERT promoter combined with BRAF and RAS mutations in Papillary Thyroid Cancer (PTC) cases in the Greek population. Polymerase Chain Reaction and sequencing were used to identify TERT promoter (C228T, C250T, CC243-243TT) mutations, the BRAF (T1799A) mutation and mutations in codons 12, 13, 61 of the HRAS, KRAS and NRAS genes. The most common C228T TERT promoter mutation was identified in 2 PTC cases co-existing with the BRAF mutation. The BRAF T1799A mutation was detected in 10 PTC cases, while two different NRAS mutations in codon 61 (C181A and A182G) were found in 2 PTC cases. These mutations occur in a mutually exclusive manner. Our results indicate that despite the low frequencies, the study of the specific mutations should be encouraged because they are indicative of aggressive forms of thyroid cancer of the papillary histotype in this patient cohort, thus providing insights towards their therapeutic management.