CD34 and acute myeloid leukemia: For example, on the identification of CSC in acute myelocytic leukemia (AML), where the cells were fractionated on the basis of CD34 and CD38 expression, demonstrating that only the CD34+CD38− cells, but not the CD34+CD38+ or CD34− cells, were able to engraft immunocompromised mice, replicating many aspects of human AML (19).