Validation of Immunohistochemistry for the Detection of BRAF V600E-Mutated Lung Adenocarcinomas

Abstract

BRAF V600E mutation, a missense mutation in exon 15 resulting in valine substitution for glutamate at position 600 within the kinase domain of BRAF oncogene, is found in a subset of lung adenocarcinoma (ADC). The usefulness of immunohistochemistry (IHC) as an alternative diagnostic tool has not been validated. Moreover, the clinical information of patients with BRAF V600E-mutated lung ADC is limited. We retrospectively identified 31 lung ADCs diagnosed with BRAF V600E mutation by standard molecular sequencing methods and reviewed their clinical characteristics and pathological features. An anti-BRAF V600E monoclonal VE1 antibody for IHC was used to confirm the expression patterns. The series was comprised of 99 cases, 29 with BRAF V600E mutation and 70 without BRAF V600E but with other types or undetected mutations. The majority of BRAF V600E-mutated biopsied tissues were poorly differentiated and micropapillary patterns. Application of the IHC VE1 assay was highly feasible in primary/metastatic sites or effusion blocks, yielding positive findings in 28 of 29 (96.6%) BRAF V600E-mutated tumors and negative results in 69 of 70 (98.6%) tumors harboring other types or undetected mutations. Patients who received pemetrexed/platinum-based rather than mutation-targeted chemotherapy as the first-line therapy for metastatic disease showed median overall survival of 15.5 months. Our findings indicated that VE1 antibody-based IHC analysis demonstrated high sensitivity and specificity to detect BRAF V600E-mutated lung ADCs in tissues from primary or metastatic sites.

Immunohistochemical Study Using Monoclonal VE1 Antibody Can Substitute the Molecular Tests for Apprehension of BRAF V600E Mutation in Patients with Non-small-Cell Lung Carcinoma

“…We noted that VE1 monoclonal antibody achieved high concurrence rates with the molecular practice ( p < 0.05). Similar concordance pattern was reported by Ilie et al [17], Sasaki et al [19], and Gow et al [28] who found that IHC with VE1 clone is a very sensitive and specific method for the detection of mutant BRAF gene in lung adenocarcinoma. Likewise, Luk et al [21] demonstrated that BRAF IHC was positive in two out of three cases with V600E gene alteration, and their results were steady with the Sequenom massARRAY platform results.…”

VE1 immunohistochemistry is an adjunct tool for detection of BRAFV600E mutation: Validation in thyroid cancer patients

“…Over the past 5 to 10 years, the clinical utility of IHC with mutation‐specific antibodies has increased considerably and implemented clinically for the detection of mutation 24,25 . Several studies have been reported on the performance of VE1 IHC technique to detect the BRAF V600E mutation, and most of these reports showed exceptional concordance between this method and molecular genotyping, thus IHC can be used as an alternative method to Sanger sequencing 1,26,27 .…”

A highly sensitive and specific real-time quantitative PCR for BRAF V600E/K mutation screening

“…Compared with direct detection at sequence level for identifying mutations of interest, immunohistochemistry offers several advantages, such as being easy to perform, convenient and good single-cell level detection sensitivity, while reflecting faithfully the expression of functional mutant molecules, instead of the upstream coding mutant templates, as the most important. Although the BRAF V600E-specific antibody (clone VE1) has been widely used in BRAF V600E detection, false-positive and false-negative results are frequently observed in various types of cancers, including lung cancer 25,[34][35][36][37][38] . The false-negative results are frequently attributed to non-optimized pre-analytical procedures or low tumor content in specimen, but the causes for false-positivity are still largely unknown.…”