BRAF and pilocytic astrocytoma: Nevertheless, although the KIAA1549(16)-BRAF(9) fusion was most common in brain grade I pilocytic astrocytomas (64.3%, 9/14), the KIAA1549(15)-BRAF(9) fusion was the most common in spinal grade I pilocytic astrocytomas (80%, 8/10 Fisher test: p = 0.65).