We evaluated the utility of the VE1 antibody that can detect a mutant protein resulting from the BRAF V600E mutation as a diagnostic tool for thyroid fine-needle aspiration cytology (FNAC).
We performed VE1 immunocytochemistry on 202 FNAC specimens from surgically confirmed thyroid nodules. The results were compared with the molecular analyses of the BRAF mutation in these specimens matched with their corresponding histology.
Diagnoses of FNAC specimens included benign (9.4%), atypia of undetermined significance/follicular lesion of undetermined significance (11.4%), follicular neoplasm/suspicious for follicular neoplasm (2.0%), suspicious for malignancy (9.4%), and malignancy (65.8%). VE1 immunostaining was positive in 71.3% of FNAC specimens. The overall sensitivity of the VE1 antibody was 88.8%, specificity was 71.2%, positive predictive value was 88.2%, negative predictive value was 72.4%, and diagnostic accuracy was 83.7%.
VE1 immunocytochemistry in thyroid FNAC as a screening test for BRAF mutations is highly specific for malignant category cases but can be suboptimal due to its high false-positive rate for the nonmalignant cases.