BRAF V600E mutation analysis increases diagnostic accuracy for papillary thyroid carcinoma in fine-needle aspiration biopsies.
OBJECTIVE
Papillary thyroid carcinoma (PTC) represents the majority of differentiated thyroid cancers, presenting the V600E activating BRAF mutation in 29-83% of cases. The aim of our study is to analyze the influence of BRAF mutation analysis on the diagnostic accuracy of fine-needle aspiration biopsy (FNAB) in patients with suspected PTC.


METHODS
Thyroid cytoaspirates from 469 nodules (size: 1.1+/-0.8 cm) with ultrasonographic features suspicious of malignant lesion, performed in 374 patients, were submitted to cytological evaluation and to biomolecular analysis, carried out after somatic DNA isolation, specific PCR amplification, and subsequent automated direct sequencing. All PCR fragments were also processed by specific enzyme restriction analysis.


RESULTS
BRAF V600E mutation was found in 48 samples, 41 of which were also cytologically diagnosed as PTC, with histologic confirmation after thyroidectomy. Total thyroidectomy was perfomed also in seven patients with negative cytology but positive BRAF mutation, with histological confirmation of PTC in all. Among the 429 BRAF-negative samples, 407 had negative cytology for PTC, while 22 were diagnosed as suspected PTC and underwent total thyroidectomy with histological diagnosis of PTC in 17 and benign lesion in five. The prevalence of BRAF V600E mutation among histologically diagnosed PTC patients was 64%. Biomolecular analysis significantly increased cytology sensitivity for PTC from 77.3 to 86.7% (P<0.01).


CONCLUSIONS
These data indicate that BRAF V600E mutation analysis can significantly improve FNAB diagnostic accuracy. However, biomolecular analysis is complementary to cytology, which should always be performed.
Zatelli
Maria Chiara
MC
Section of Endocrinology, Department of Biomedical Sciences and Advanced Therapies, University of Ferrara, Via Savonarola 9, 44100 Ferrara, Italy.
Trasforini
Giorgio
G
Leoni
Stefania
S
Frigato
Gemma
G
Buratto
Mattia
M
Tagliati
Federico
F
Rossi
Roberta
R
Cavazzini
Luigi
L
Roti
Elio
E
degli Uberti
Ettore C
EC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D044963:Biopsy, Fine-Needle; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods; D005260:Female; D018698:Glutamic Acid / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D012150:Polymorphism, Restriction Fragment Length; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D014633:Valine / Q000235:genetics; D055815:Young Adult
D018698:Glutamic Acid; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D014633:Valine