BRAF

BRAF is a serine/threonine kinase within the MAPK signaling pathway, and the BRAF V600E mutation (Val600Glu) is an activating somatic alteration detectable by immunohistochemistry. BRAF V600E IHC uses the VE1 antibody to identify cytoplasmic staining in mutation‑positive tumour cells and is sensitive and specific for confirming BRAF‑mutated melanoma, papillary thyroid carcinoma, and colorectal carcinoma. This stain assists in distinguishing sporadic MSI‑high colorectal cancers from Lynch syndrome associated cases, identifying melanomas likely to benefit from BRAF inhibitor therapy, and aiding in differentiating Spitzoid melanomas from Spitz tumors. Interpretation can be challenging in heavily pigmented lesions where melanin mimics the chromogen (1-2).

Recommended Controls

Criteria for acceptable staining is a strong cytoplasmic staining pattern. The recommended positive control to include a positive melanoma tumour which will demonstrate a strong cytoplasmic staining pattern, as well as low or negative expressor of the antigen. A section of appendix or a normal skin can by used as a negative control. There should be no cytoplasmic staining of epithelial cells in the skin or appendix.

Expected staining pattern

Malignant Melanoma

Normal Skin

Disclaimer

These methods are intended as a guide only. Laboratories that wish to implement these methods should perform internal validation/verification prior to use. The RCPAQAP does not make any claim or warranty for the accuracy or performance of these methods.