NPM1 and acute myeloid leukemia: We chose GPR56 to define the LSC population because its gene belongs to the core 17-gene stemness gene expression signature of AMLs and because its surface expression enriches for AML initiating potential across a broad spectrum of AML subsets (including CD34- NPM1-mutated AMLs) and is stable upon short-term ex vivo culture [15, 16, 19].