Diagnostic value of immunohistochemistry for the detection of the BRAF V600E mutation in colorectal carcinoma.

PURPOSE V600E is the most common activating BRAF mutation in colorectal carcinomas (CRCs). It is a crucial biomarker for patient selection and response to targeted therapy with BRAF V600E inhibitors. Previous studies using immunohistochemistry (IHC) have shown different results. In this study, we evaluated the IHC expression of the mutated BRAF protein in archival material from CRC specimens and correlated it with DNA sequence analysis. METHODS 51 cases of primary colon adenocarcinoma were stained with BRAF V600E-specific clone VE1 antibody against mutated BRAF protein. DNA sequence analysis was performed and the results were compared. RESULTS BRAF V600E protein was detected in the cytoplasm of neoplastic cells in 15 of the 51 examined cases (29.4%). The correlation between IHC staining and DNA sequence analysis showed 93.75% sensitivity and 100% specificity. CONCLUSIONS Our data show that IHC could be used in routine clinical practice as a screening method for BRAF V600E mutant protein detection in CRC patients.