Immunohistochemical Detection of the BRAF V600E-mutated Protein in Papillary Thyroid Carcinoma American Journal of Surgical Pathology , 05/25/2012

Koperek O et al. – The data show that the expression of the mutated BRAF V600 protein and thus the corresponding BRAF mutation seems not to be per se a marker of aggressiveness but is already seen in clinically indolent microcarcinomas. Nevertheless, the investigation of BRAF V600E protein expression might be of clinical interest especially in therapy-resistant disease, as new therapeutics inhibiting the mutated protein are clinically available.

• Authors evaluated the expression of the mutated BRAF V600E protein in 144 cases of PTC using a novel mutation-specific antibody
• Seventy-six PTCs (52.8%) showed unequivocal diffuse cytoplasmic expression of the mutated BRAF protein, and the T1799A point mutation was confirmed by sequencing analysis in selected cases.

• No statistical difference in V600E BRAF protein expression was seen between microcarcinomas and macrocarcinomas.
• Further, no significant correlation of V600E expression with clinicopathologic parameters of aggressiveness such as lymph node metastasis, peritumoral infiltration, or perithyroidal infiltration was found.
• BRAF V600E protein expression was significantly more common in tumors with tall cell or oncocytic features but was less common in tumors with follicular growth pattern.
• Diffuse sclerosing, solid and follicular variants did not show the mutated BRAF protein.
• Immunohistochemical detection of the mutated V600E BRAF protein in PTC may facilitate mutational analysis in the clinical setting.