Immunohistochemistry is a feasible method to screen BRAF V600E mutation in colorectal and papillary thyroid carcinoma.

To investigate whether immunohistochemistry (IHC) could be used to screen BRAF mutation status in formalin-fixed paraffin-embedded (FFPE) colorectal carcinoma (CRC) and papillary thyroid carcinoma (PTC) samples. Eight surgical resected samples, including 2 CRCs with mutated BRAF V600E, 2 PTCs with mutated BRAF V600E, 2 CRCs with wild-type BRAF and 2 PTCs with wild-type BRAF, were selected to explore the optimized IHC conditions for BRAF V600E (VE1) immunostaining using BenchmarkXT automated immunostainer VENTANA Medical System. BRAF V600E status was tested by optimized IHC and ARMS-PCR methods in 255 samples (123 CRCs and 132 PTCs). Sanger sequencing was performed to validate the BRAF V600E status if discordant results were found between optimized IHC and ARMS-PCR methods. Antigen retrieval time in 32 min and 64 min showed satisfactory intensity and homogeneity of BRAF V600E staining in CRC and PTC samples, respectively. The concordance between IHC and ARMS/Sanger sequencing was 99.2% (122/123) in CRCs and 96.2% (127/132) in PTCs. In CRCs, the sensitivity of IHC staining for BRAF V600E was 100% (3/3) and the specificity was 99.1% (119/120). In PTCs, the sensitivity was 100% (106/106) and specificity was 80.8% (21/26). The overall concordance across all cases was 97.6% (249/255). The appropriate antigen retrieval protocol is critical for accurate analysis of BRAF V600E status by Benchmark XT automated immunostainer. IHC is a suitable method to screen BRAF V600E mutation in FFPE samples of CRCs and PTCs.

Zhang X ，Wang L ，Wang J ，Zhao H ，Wu J ，Liu S ，Zhang L ，Li Y ，Xing X ... -  《-》

Specific immunohistochemical detection of the BRAF V600E mutation in primary and metastatic papillary thyroid carcinoma.

To evaluate the clinical value of immunohistochemistry (IHC) using anti-BRAF V600E antibody (clone VE1) for specific detection of the BRAF V600E mutant protein in formalin-fixed paraffin-embedded papillary thyroid carcinoma (PTC) specimens. A total of 118 PTC cases and 116 control cases processed between January 2008 and June 2010 were selected and created tissue microarrays (TMAs) for the study. BRAF V600E (VE1) IHC was performed on tissue sections from PTC cases to determine mutation status. Molecular tests (Sanger sequencing/ARMS) were used to confirm the BRAF V600E gene mutation in primary PTC. A uniformly cytoplasmic staining throughout the tumors was observed in IHC-positive cases. BRAF V600E was detected in 68.6% (81/118) of PTC samples by IHC and in 61.9% (73/118) by Sanger sequencing/ARMS. The overall concordance between IHC and Sanger sequencing/ARMS was 93.2% (110/118). The sensitivity and specificity of the BRAF V600E IHC was 100% (73/73) and 82.2% (37/45), respectively. Positive and negative predictive values were 90.1% (73/81) and 100% (37/37), respectively. Expression of the BRAF V600E mutant protein was detected in all of 59 cases of primary carcinoma and corresponding metastatic carcinoma in lymph nodes. The concordance between IHC staining in primary and metastatic PTC was 100% (59/59). IHC using VE1 antibody for detection of the BRAF V600E mutant protein expression in PTC showed high sensitivity and acceptable specificity, which are critical for diagnostic purposes. IHC staining for BRAF V600E showed uniformly cytoplasmic expression in both primary tumor and metastatic nodes. Therefore, IHC has high practical value for the detection of the BRAF V600E mutation in metastatic and primary PTC.

Zhu X ，Luo Y ，Bai Q ，Lu Y ，Lu Y ，Wu L ，Zhou X ... -  《-》

Assessment of BRAF V600E Status in Colorectal Carcinoma: Tissue-Specific Discordances between Immunohistochemistry and Sequencing.

Although sequencing provides the gold standard for identifying colorectal carcinoma with BRAF V600E mutation, immunohistochemistry (IHC) with the recently developed mouse monoclonal antibody VE1 for BRAF V600E protein has shown promise as a more widely available and rapid method. However, we identified anecdotal discordance between VE1 IHC and sequencing results and therefore analyzed VE1 staining by two different IHC methods (Leica Bond and Ventana BenchMark) in whole tissue sections from 480 colorectal carcinomas (323 BRAF wild-type, 142 BRAF V600E mutation, and 15 BRAF non-V600E mutation). We also compared the results with melanomas and papillary thyroid carcinomas (PTC). With the Bond method, among 142 BRAF V600E-mutated colorectal carcinomas, 77 (54%) had diffuse VE1 staining and 48 (33%) had heterogeneous staining, but 17 (12%) were negative. Among 323 BRAF wild-type colorectal carcinomas, 196 (61%) were negative, but 127 (39%) had staining, including 7 with diffuse staining. When positivity was defined as staining in ≥ 20% of tumor cells, VE1 IHC had sensitivity of 75% and specificity of 93% for BRAF V600E mutation. With the Ventana method, among 57 BRAF V600E-mutated colorectal carcinomas, 36 (63%) had diffuse VE1 staining, whereas 6 (11%) had no or weak (<20% of tumor cells) staining. Among 33 BRAF wild-type colorectal carcinomas, 16 (48%) had no or weak staining, whereas 15 (45%) had heterogeneous staining. In contrast with colorectal carcinoma, Bond and Ventana VE1 IHC in melanoma and PTC were highly concordant with sequencing results. We conclude that VE1 IHC produces suboptimal results in colorectal carcinoma and should not be used to guide patient management.

Estrella JS ，Tetzlaff MT ，Bassett RL Jr ，Patel KP ，Williams MD ，Curry JL ，Rashid A ，Hamilton SR ，Broaddus RR ... -  《-》

Investigation of BRAF V600E detection approaches in papillary thyroid carcinoma.

The detection of BRAF V600E mutation in papillary thyroid carcinoma (PTC) may be helpful to offer diagnostic confirmation. Additionally, such detection may provide a targeted therapeutic approach for the radioactive iodine resistant patients to predict adverse outcomes. To compare the results of immunohistochemistry (IHC) method using the anti-BRAF V600E (VE1) antibody with the Quantitative real-time polymerase chain reaction (qPCR) approach in examining BRAF V600E mutation in PTC, we investigated the sensitivity and specificity of BRAF V600E (clone VE1) mouse monoclonal antibody in detecting the BRAF V600E mutation and correlated BRAF V600E mutation with clinicopathologic features in PTC. IHC and qPCR were performed in 40 cases of paraffin-embedded PTCs tissues. The association between BRAFV600E mutation and clinicopathologic features of PTC was assessed with the χ2 test. The concordance rate between IHC and qPCR analyses was 95% (38/40). The BRAF V600E (VE1) antibody has a sensitivity of 100% (34/34) and specificity of 66.67% (4/6) for detecting the mutation. Our study showed that there was no significant association of BRAF V600E mutation with the gender, age, tumor size and lymph node metastasis in PTCs. We may draw the conclusion that detection of BRAF V600E mutation by immunohistochemistry is highly sensitive and specific. Immunohistochemical detection of the mutated BRAF V600E protein in PTC may facilitate mutational analysis in the clinical setting.

Chen D ，Qi W ，Zhang P ，Zhang Y ，Liu Y ，Guan H ，Wang L ... -  《-》

Clinical utility of immunohistochemistry for the detection of the BRAF v600e mutation in papillary thyroid carcinoma.

BRAF V600E mutation is the most common genetic alteration in papillary thyroid cancer (PTC). We used a mutation-specific antibody for immunohistochemical (IHC) detection of the BRAF V600E mutation and correlated expression with clinicopathologic features. The study was designed to validate the accuracy and determine the clinical importance of IHC detection of the BRAF V600E mutation in PTC. Direct sequencing and IHC for BRAF V600E mutation was performed in 37 consecutive patients with PTCs. IHC was scored on an intensity proportion scale. IHC positive tumors were stratified into intensity categories. The categories were assessed for clinicopathologic variables, including age, extrathyroidal extension, lymphovascular invasion, and lymph node metastases. A total of 25 PTCs were BRAF V600E-positive and 12 were BRAF mutation-negative on IHC. The BRAF V600E mutation-specific antibody had a sensitivity of 89% and specificity of 100% for detecting the mutation. Tumors with high-intensity staining were more likely to have extrathyroidal extension. IHC is an accurate method for the detection of the BRAF V600E mutation in PTC, and its ability to quantify the mutation expression may serve as a better predictor of tumor behavior than molecular sequencing. It provides a potentially rapid, easily applicable, and economic alternative to current techniques.

Zagzag J ，Pollack A ，Dultz L ，Dhar S ，Ogilvie JB ，Heller KS ，Deng FM ，Patel KN ... -  《-》