Specificity
The BRAF gene encodes a cytoplasmic serine-threonine kinase, which initiates the activation of the mitogen-activated protein kinase (MAPK) signalling pathway. The oncogenic mutations in the kinase region of BRAF gene result in constitutive activation of the MAPK signalling pathway, leading to increased cell proliferation, resistance to apoptosis and tumor progression. The most common of all activating BRAF mutations leads to a substitution of valine (V) to glutamic acid (E) at the position 600 of the amino acid sequence. The BRAF V600E mutation is an important predictive and prognostic biomarker. The BRAF V600E mutation is detected in approximately 8% of all solid tumours, including 45% of papillary thyroid carcinomas, 40-60% of melanomas, 5-15% of colorectal adenocarcinomas, 35% of serous low grade and borderline ovarian carcinomas, 1-3% of non-small cell lung cancers, and 5-7% of cholangiocarcinomas. Furthermore, the BRAF V600E mutation is found in 100% of hairy cell leukaemia, 54% Erdheim-Chester disease, 38% of Langerhans cell histocytoses and 60% of pleomorphic xanthoastrocytomas.
