KIAA1549 and pleomorphic xanthoastrocytoma: Previous studies have revealed that KIAA1549–BRAF fusions are a hallmark mutation in pediatric pilocytic, pilomyxoid, and diffuse astrocytomas of the brain.20 Other studies have demonstrated that BRAFV600E mutations are common in grade 2 pleomorphic xanthoastrocytomas, pleomorphic xanthoastrocytomas with anaplasia, grade 1 gangliogliomas, grade 3 anaplastic gangliogliomas, and pilocytic astrocytomas in the brain.