Interestingly, the spectrum of MAPK pathway alterations is different across all anatomic locations of pilocytic astrocytomas, with the KIAA1549:BRAF fusion being very frequent in the cerebellum (~90%), but less common in supratentorial locations, FGFR1 alterations were common in midline structures, while BRAFV600E and NRTK1 fusion were more common in supratentorial tumors [119]. The gene discussed is FGFR1; the disease is pilocytic astrocytoma.