ECE2007 Poster Presentations (1) (659 abstracts)
BRAF point mutations are found in 29-69% of papillary thyroid carcinoma (PTC). BRAF is a serine-threonine kinase involved in the phoshorylation of MAPK signaling pathway. The mutation is located in the exon 15 of BRAF, resulting in the substitution of valine to glutamate at codon 600 (V600E). Mutation generates unregulated B-Raf activity that leads to increased cellular proliferation. The aim of this study was to determine the frequency of BRAF mutation in the Czech population and its changes in 1960-2006. We examined 145 of PTC: 92 paraffin-embedded formalin-fixed tissue samples, 44 fresh frozen tissues and 9 wash-out material from fine-needle aspiration biopsies (FNAB) after signing informed consent approved by ethical committee. For assessment of influence of Chernobyl nuclear accident we devided samples into 5 periods - one period before and four periods after the accident. DNAs from paraffin-embedded samples were extracted using the QIAamp DNA Blood Mini Kit and frozen samples using Trizol reagent. BRAF gene was screened using the single strand conformation polymorphism method (SSCP) and verified by direct sequencing. The V600E mutation was detected in 56 samples (38,6%). All BRAF mutations except one were heterozygous. Surprisingly, in the period before Chernobyl nuclear accident no BRAF mutation was found, in other periods 56 mutations were detected (41,2%). The female to male ratio was 3,7:1, mutation was found in 48,4% of male and in 36% of female patients. In our series difference between age at diagnosis in patients with and without mutation was not significant. Our study confirms a high rate of BRAF V600E mutation in Czech PTC patients. Results indicate that the mutation is the most frequent genetic alteration found in PTC and it could be used as a reliable genetic marker of PTC and applied for FNAB before surgery.
This study was supported by IGA MZ CR NR/7806-3.