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Frequency assessment of BRAF mutation, KRas mutation, and RASSF1A methylation in nodular goitre based on fine-needle aspiration cytology specimens
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Abstract
Introduction: Standard pre-operative diagnosis of nodular goitre is not always conclusive. The decision about nodular goitre surgery is increasingly based on molecular methods. The aim of the study was to determine BRAF T1799A mutation and KRas proto-oncogene mutation, and the analysis of RASSF1A promoter methylation level in cytological material obtained from FNAB specimens of thyroid nodules.
Material and methods: The study population consisted of 85 women and 12 men. The study material was genomic DNA isolated from peripheral blood and thyroid bioptates. Pyrosequencing was used for the evaluation of RASSF1 methylation level. KRas mutation was investigated with Sanger sequencing. BRAF mutation was analysed by standard methods of real-time amplification detection (real-time PCR) with the use of specific starters surrounding the mutated site.
Results: A significant positive correlation was demonstrated between mean methylation of four CpG islands of RASSF1A gene and thyroid tumour volume and its largest diameter (p < 0.05). KRas mutation was not detected in any of the 97 patients. In 7/85 subjects (8.2%) BRAF mutation was observed. In 6/7 patients with BRAF mutation, FNAB of thyroid nodules confirmed a benign nature of the lesions; the material was non-diagnostic in one patient, and papillary thyroid cancer was diagnosed on the basis of postoperative histopathology assessment.
Conclusions: The results of genetic tests reported in our study indicate that the presence of BRAF mutation or higher RASSF1A methylation levels in FNAB cytology specimens of benign lesions may be useful in the assessment of oncological risk, while the evaluation of KRas proto-oncogene mutation is not a valuable test in pre-operative diagnosis of nodular goitre. (Endokrynol Pol 2015; 66 (5): 384–393)
Abstract
Introduction: Standard pre-operative diagnosis of nodular goitre is not always conclusive. The decision about nodular goitre surgery is increasingly based on molecular methods. The aim of the study was to determine BRAF T1799A mutation and KRas proto-oncogene mutation, and the analysis of RASSF1A promoter methylation level in cytological material obtained from FNAB specimens of thyroid nodules.
Material and methods: The study population consisted of 85 women and 12 men. The study material was genomic DNA isolated from peripheral blood and thyroid bioptates. Pyrosequencing was used for the evaluation of RASSF1 methylation level. KRas mutation was investigated with Sanger sequencing. BRAF mutation was analysed by standard methods of real-time amplification detection (real-time PCR) with the use of specific starters surrounding the mutated site.
Results: A significant positive correlation was demonstrated between mean methylation of four CpG islands of RASSF1A gene and thyroid tumour volume and its largest diameter (p < 0.05). KRas mutation was not detected in any of the 97 patients. In 7/85 subjects (8.2%) BRAF mutation was observed. In 6/7 patients with BRAF mutation, FNAB of thyroid nodules confirmed a benign nature of the lesions; the material was non-diagnostic in one patient, and papillary thyroid cancer was diagnosed on the basis of postoperative histopathology assessment.
Conclusions: The results of genetic tests reported in our study indicate that the presence of BRAF mutation or higher RASSF1A methylation levels in FNAB cytology specimens of benign lesions may be useful in the assessment of oncological risk, while the evaluation of KRas proto-oncogene mutation is not a valuable test in pre-operative diagnosis of nodular goitre. (Endokrynol Pol 2015; 66 (5): 384–393)
Keywords
nodular goiter; fine-needle aspiration biopsy; BRAFV600E mutation; KRas mutation; RASSF1A methylation
About this articleTitle
Frequency assessment of BRAF mutation, KRas mutation, and RASSF1A methylation in nodular goitre based on fine-needle aspiration cytology specimens
Journal
Issue
Article type
Original paper
Pages
384-393
Published online
2015-10-12
Page views
1744
Article views/downloads
2502
DOI
10.5603/EP.2015.0048
Pubmed
Bibliographic record
Endokrynol Pol 2015;66(5):384-393.
Keywords
nodular goiter
fine-needle aspiration biopsy
BRAFV600E mutation
KRas mutation
RASSF1A methylation
Authors
Monika Koziołek
Agnieszka Bińczak-Kuleta
Maria Stepaniuk
Miłosz Parczewski
Elżbieta Andrysiak-Mamos
Anna Sieradzka
Krzysztof Safranow
Lilianna Osowicz-Korolonek
Bartosz Kiedrowicz
Andrzej Kram
Andrzej Ciechanowicz
Anhelli Syrenicz
