The prognostic significance of the BRAFV600E mutation in papillary thyroid carcinoma detected by mutation-specific immunohistochemistry

SummaryAimsBRAFV600E mutation has been shown in a large metaanalysis to be an independent prognostic marker for papillary thyroid carcinoma (PTC) with poorer survival and higher recurrence rates.MethodsWe studied prevalence of BRAFV600E mutation in 77 patients with PTC from an Australian cohort using competitive polymerase chain reaction (C-PCR) and immuno- histochemistry (IHC) with BRAFV600E-specific antibody, VE1. Clinicopathological parameters, recurrence and mortality were analysed according to BRAFV600E mutation status.ResultsMedian follow-up was 84.5 months. BRAFV600E mutation was demonstrated in 65% of cases combining both C-PCR and IHC; in 71% (37/77) of tumours >1cm and 52% (13/25) of microcarcinomas (<1 cm). IHC was positive in 69% (49/71) and C-PCR in 53% (41/77); 87% (67/77) of our patients were treated with total thyroidectomy and 65% (50/77) also had radioactive ablation. BRAFV600E positive tumours had a significantly higher rate of subsequent lymph node metastases (p — 0.035). Significant association was found between BRAFV600E mutation and male sex (p—0.034), but not between age >45 years at diagnosis, size of primary tumour, extrathyroidal extension, lymph node or distant metastases or clinical stage at diagnosis.ConclusionsBRAFV600E mutation in PTC determined by IHC is associated with significantly increased risk of lymph node recurrence.