Title: Detection of BRAF Mutations on Direct Smears of Thyroid Fine Needle Aspirates through Cell Transfer Technique Concise Title: BRAF on cell transfer cytology

Objectives: To determine the utility of the cell transfer technique (CTT) for the BRAF molecular testing on thyroid fine-needle aspirates (FNA). Methods: Polymerase chain reaction (PCR)based BRAF molecular testing was performed on tissues obtained through CTT from both airdried and ethanol-fixed direct smears of thyroid FNA, and then compared with the corresponding thyroidectomy formalin-fixed, paraffin-embedded (FFPE) tissues on 30 cases. Results: BRAF testing was successfully performed on 29/30 air-dried CTT, 27/30 ethanol-fixed CTT, and 27/30 FFPE. The results exhibited 11, 13, and 13 BRAF mutations and 18, 14, and 14 wild types for the air-dried CTT, the ethanol-fixed CTT, and the FFPE, respectively. The concordance rate was 96% between air-dried and ethanol-fixed CTT, 88% between air-dried CTT and FFPE, and 92% between ethanol-fixed CTT and FFPE. Conclusions: PCR-based BRAF mutational testing can be reliably performed on the direct smears of the thyroid FNA through the application of the CTT.