Papillary thyroid cancer, the commonest histological type, has been extensively reported as having BRAF proto-oncogene mutations (most commonly the V600E mutation). There is great interest in BRAF as a molecular marker, particularly as a prognostic factor that may guide the extent of surgery, especially when considering neck dissection. Although the findings of this paper, from a group in Paris, do not support BRAF V600E mutation as a marker of poor prognosis, there appears to be an emerging role for this molecular marker in the initial diagnostic phase of thyroid nodule work-up. The paper outlines the technique required to obtain objective accurate V600E status from initial thyroid nodule fine needle aspiration (FNA) using PCR. Their study of 160 patients undergoing thyroid nodule FNA identified a V600E mutation rate for malignant cases of 81%, confirmed later on histological diagnosis. It was not detected in non-papillary thyroid cancer cases. In nodules that were suspicious for malignancy, all those that had final histology revealing papillary carcinoma had V600E positive FNAs. No V600E mutations were identified in the pre-operatively diagnosed non-malignant follicular neoplasms. Specificity and positive predictive value were both 100%, sensitivity was 75% and negative predictive value was 46%. The authors put forward that this marker, with a current test cost of £50, may have a role in decision-making, with patients being counselled for total versus hemi-thyroidectomy for FNA samples that are suspicious for malignancy. 

BRAF V600E detection in cytological thyroid samples: a key component of the decision tree for surgical treatment of papillary thyroid carcinoma.
Collet JF, Lacave R, Hugonin S, et al.
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Aileen Lambert

Great Ormond Street Hospital, London, UK.

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