While many human AML samples do in fact have populations with cellular phenotypes resembling progenitor cells (L-GMP-like, such as CD34+CD38+) that demonstrate leukaemogenic activity in xenograft studies, the vast majority of human AML patient samples show highest leukaemic activity in cells that resemble HSC (CD34+CD38−) (Bonnet and Dick, 1997; Goardon et al, 2011; Sarry et al, 2011). The gene discussed is CD38; the disease is acute myeloid leukemia.