KIAA1549-BRAF is a gene fusion resulting from a tandem duplication event involving the BRAF kinase gene that have recently been identified as the most frequent genetic alteration in many cancers. The KIAA1549-BRAF fusion typically results from a 2.0 Mb tandem duplication in chromosome band 7q34. The KIAA1549:BRAF fusion gene is considered a driver genetic event in pilocytic astrocytoma and many other pediatric brain neoplasms. KIAA1549-BRAF fusion gene and BRAF (V600E) mutation may be responsible for deregulation of the Ras-RAF-ERK signaling pathway in many brain cancers.