Immunohistochemistry for BRAF(V600E) antibody VE1 performed in core needle biopsy samples identifies mutated papillary thyroid cancers.

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.

Medullary thyroid nodules by measurement of calcitonin (Ct) in aspiration needle washout in patients with multinodular goiter and moderately elevated serum Ct.

The accuracy of fine needle aspiration cytology (FNAC) is low in medullary thyroid carcinomas (MTC). Recently, a few papers analyzed the measurement of calcitonin (Ct) in washout of the needle after aspiration (WO-Ct) suggesting that this approach may be useful in patients with high serum Ct. Here we reported, for the first time in our best knowledge, 3 patients with multinodular goiter, moderately elevated serum Ct, high value of WO-Ct, and medullary outcome. These findings suggest that in presence of high serum Ct, FNAC should be performed in all nodules, and it should be combined with WO-Ct in all cases.

Phenotypic changes of the thyrocyte membrane in papillary thyroid carcinoma. A three-dimensional study.

Aim of the study was to assess the presence of structural changes in the complex carbohydrate chains of thyroid epithelia undergoing neoplastic transformation. We investigated thyroid cells from neoplastic lesions using a panel of lectins with specific affinity for distinct carbohydrate residues. Sixty samples of thyroid tissue, including normal, hyperplastic and neoplastic lesions were obtained from surgical specimens and blindly evaluated with lectin stains. Confocal microscopy was used to obtain three-dimensional (3-D) images of the samples with a positive reaction. Wheat germ agglutinin (WGA) was consistently positive on the apical membrane of papillary thyroid carcinomas (PTC), was weakly expressed in follicular carcinomas (FC) and resulted negative in normal thyrocytes and in benign conditions. The 3-D microscopy model showed that the WGA staining pattern in light microscopy corresponds to a continuous layer on the luminal surface of both papillary and tubular structures of PTC cells. The other lectins under evaluation did not provide any significant result. In conclusion, in PTC the apical border of thyrocytes showed a strong, specific and consistent staining with WGA. These findings may be related to a modified interaction of thyroglobulin molecule with thyroid cell membrane and with the expression of molecules that are involved in the process of tumorigenesis and tumor progression.