Fine-Needle Aspiration (FNAB) Molecular Analysis for the Diagnosis of Papillary Thyroid Carcinoma through BRAFv600E mutation and RET/PTC rearrangement

Objective: To evaluate BRAFV600E mutation on consecutive fine-needle aspiration biopsy (FNAB) specimens in order to assess FNAB’s usefulness in preoperative papillary thyroid carcinoma (PTC) diagnosis with the contemporaneous analysis of RET=PTC1 and RET=PTC3 rearrangements obtained from ex vivo thyroid nodules. Design: Thyroid FNABs from 156 subjects with nodules and 49 corresponding surgical samples were examined for the presence of BRAF mutation by real-time allele-specific polymerase chain reaction, confirmed with the use of a laser pressure catapulting system. Samples were also examined for RET=PTC rearrangements. The results were compared with the cytological diagnosis and histopathology. Main outcomes: 13=156 cytological examinations were diagnostic for PTC and 19=156 showed suspicious=indeterminate FNAB (12.2%). FNAB-BRAFV600E mutation was detected in 11=16 (69%) cases with histological confirmation of PTC. In our series, RET=PTC rearrangement was detected in only one case of PTC, whereas it was not present in any case of adenoma, goiter, or Hashimoto’s thyroiditis. No PTC case was found positive at the same time for BRAF mutation and RET=PTC rearrangements. Conclusion: BRAFV600E mutation detected on FNAB specimens, more than RET=PTC rearrangerangements, is highly specific for PTC and its routine research might well be an adjunctive and integrative diagnostic tool for the preoperative diagnostic iter.