These two cell populations display leukemia initiating potential upon serial transplantation and are hierarchically ordered; CD38— cells with a higher number of LSCs resembling normal lymphoid-primed multipotent progenitors (LMPP-like LSC) give rise to leukemic granulocyte-macrophage progenitors (GMP-like LSC), but not vice versa, while CD38+ cells present less LSC. The gene discussed is CD38; the disease is leukemia.