BRAF is a member of the RAF-family of kinases which plays an important role in the RAS-RAF-MEK-ERK mitotic signaling pathway. The K601E mutation results in an amino acid substitution at position 601 in BRAF, occurs within the highly conserved motif of the kinase domain. Most mutant BRAF proteins, such as K601E, have increased kinase activity and are transforming in vitro. BRAF mutations are infrequent in urothelial carcinoma and are identified in 3-5% of cases. Preclinical studies are investigating the use of MEK and RAS inhibitors in BRAF K601E mutant cell lines. The clinicopathologic effects of BRAF in this cancer type remain to be fully elucidated.