Unlike higher-grade gliomas, which usually exhibit multiple driver mutations41, most PAs exhibit a single driver somatic genetic alteration, leading to activation of the MAPK pathway related to FGFR or NTRK242 or with rearrangements generating the KIAA1549-BRAF fusion oncogene accounting for ~70% of PAs43. The gene discussed is BRAF; the disease is central nervous system cancer.