Abstract
BRAF(V600E) is the most frequent genetic mutation in papillary thyroid cancer (PTC)
and has been reported as an independent predictor of poor prognosis of these patients.
Current guidelines do not recommend the use of BRAF(V600E) mutational analysis on
cytologic specimens from fine needle aspiration due to several reasons. Recently,
immunohistochemistry using VE1, a mouse anti-human BRAF(V600E) antibody, has been
reported as a highly reliable technique in detecting BRAF-mutated thyroid and nonthyroid
cancers. The aim of this study was to test the reliability of VE1 immunohistochemistry
on microhistologic samples from core needle biopsy (CNB) in identifying BRAF-mutated
PTC. A series of 30 nodules (size ranging from 7 to 22 mm) from 30 patients who underwent
surgery following CNB were included in the study. All these lesions had had inconclusive
cytology. In all cases, both VE1 and BRAF(V600E) genotypes were evaluated. After surgery,
final histology demonstrated 21 cancers and 9 benign lesions. CNB correctly diagnosed
20/20 PTC and 5/5 adenomatous nodules. One follicular thyroid cancer and 4 benign
lesions were assessed at CNB as uncertain follicular neoplasm. VE1 immunohistochemistry
revealed 8 mutated PTC and 22 negative cases. A 100% agreement was found when positive
and negative VE1 results were compared with BRAF mutational status. These data are
the first demonstration that VE1 immunohistochemistry performed on thyroid CNB samples
perfectly matches with genetic analysis of BRAF status. Thus, VE1 antibody can be
used on thyroid microhistologic specimens to detect BRAF(V600E)-mutated PTC before
surgery.
Key words
thyroid - cancer - BRAF(V600E) - VE1 - core needle biopsy (CNB)