RUNX1T1 and leukemia: A rare cell population within BM with the surface phenotype Lin−, Sca-1+, c-Kit+ (LSK) is enriched for primitive hematopoietic stem and progenitor cells, and at the same time has been shown in the murine AML-ETO pre-leukemia model to be highly enriched for myeloproliferation-initiating, transplantable pre-leukemia stem cells [30].