Analysis of over 80,000 human tumours found somatic BRAF mutations present in 4.6% of samples, most commonly occurring in hairy cell leukaemia (72%), thyroid cancer (45%), melanoma (36%), histiocytosis (19%), colorectal cancer (12%), and non-hairy cell leukaemia mature B cell neoplasms (3%) [21,22]. This evidence concerns the gene BRAF and colorectal cancer.