BRAF and pilomyxoid astrocytoma: BRAF fusion or duplication: Of 23 patients with pilocytic or pilomyxoid astrocytomas who had testing for BRAF fusions or duplications performed on all paired surgical specimens, 15 (65%) tested positive at diagnosis and remained positive at recurrence (including nine patients who received systemic therapy [most with cytotoxic chemotherapy, three with MEK inhibitors (trametinib or selumetinib)] and one who received irradiation prior to subsequent surgery; Table 2).