BRAF represents one of the most frequently mutated protein kinase genes in human 
tumours. The mutation is commonly tested in pathology practice. BRAF mutation is 
seen in melanoma, papillary thyroid carcinoma (including papillary thyroid 
carcinoma arising from ovarian teratoma), ovarian serous tumours, colorectal 
carcinoma, gliomas, hepatobiliary carcinomas and hairy cell leukaemia. In these 
cancers, various genetic aberrations of the BRAF proto-oncogene, such as 
different point mutations and chromosomal rearrangements, have been reported. 
The most common mutation, BRAF V600E, can be detected by DNA sequencing and 
immunohistochemistry on formalin fixed, paraffin embedded tumour tissue. 
Detection of BRAF V600E mutation has the potential for clinical use as a 
diagnostic and prognostic marker. In addition, a great deal of research effort 
has been spent in strategies inhibiting its activity. Indeed, recent clinical 
trials involving BRAF selective inhibitors exhibited promising response rates in 
metastatic melanoma patients. Clinical trials are underway for other cancers. 
However, cutaneous side effects of treatment have been reported and therapeutic 
response to cancer is short-lived due to the emergence of several resistance 
mechanisms. In this review, we give an update on the clinical pathological 
relevance of BRAF mutation in cancer. It is hoped that the review will enhance 
the direction of future research and assist in more effective use of the 
knowledge of BRAF mutation in clinical practice.