This patient’s diagnostic tumor contained multiple driver lesions, but some appeared clonal (heterozygous ARID1A mutation with allelic fraction approximating 50%), while others appeared to be present in only a subclonal fraction of cells studied (incomplete ATRX deletion in this male patient and inferred FGFR1 mutation in 30% of cells). The gene discussed is FGFR1; the disease is neoplasm.