Finally, several lines of evidence support the clinical relevance of what is commonly referred to in the field as the leukemic stem cell (LSC) hypothesis: (1) a higher engraftment capacity in the bone marrow of murine recipients correlates with worse survival [58], (2) patients whose whole AML samples had a gene expression profile similar to LSCs or HSCs had worse survival and could risk stratify patients independent of known prognostic factors [59], and (3) patients with a high burden of CD34 + CD38- AML cells at diagnosis correlated with poor survival [41,42]. Here, CD38 is linked to acute myeloid leukemia.