Furthermore, in contrast to melanoma, monotherapy with MEK inhibitors may also be effective in pilocytic astrocytoma: in a phase 2 study of selumetinib on paediatric patients with pilocytic astrocytoma with either KIAA1549–BRAF fusion or BRAF V600E mutation, a sustained response rate was seen in 9/25 (36%) of patients, and prolonged stable disease in 11/25 (44%) [33]. The gene discussed is BRAF; the disease is melanoma.