Immunohistochemistry as a quick screening method for clinical detection of BRAF(V600E) mutation in melanoma patients.

With the increased uses of targeted therapeutics, diagnostic detection of target mutations becomes essential for the effective clinical applications of targeted therapeutics. Currently, there are two types of methods detecting target mutations in clinics: one is based on DNA sequence and the other uses the newly developed mutation-specific antibodies recognizing mutated proteins. Each method has its own advantages and disadvantages. Here, we explored the sensitivity and specificity of a new commercially available BRAF(V600E) mutation-specific mouse monoclonal antibody. Using routine manual immunohistochemistry (IHC), we tested tumor tissues from 38 melanoma patients. For those melanoma tissues with abundant endogenous melanin, we pretreated the tumor tissues with 3 % hydrogen peroxide to remove melanin for reliable signal detection. We also performed DNA sequencing and ARMS-PCR analyses for these 38 tumor samples. Comparing to the results from DNA-based detection methods, the IHC method with this BRAF(V600E) mutation-specific antibody displayed 100 % sensitivity and 92.9 % specificity. Hence, this IHC detection is sensitive for clinic uses as a simple, fast, inexpensive, and reliable method to screen cancer patients for the BRAF(V600E) mutation and could be easily adapted for use in most hospital pathology laboratories.