STAT1 and acute myeloid leukemia: In a separate RPPA that compared expression in bulk, CD34+ and CD34+/CD38− populations derived from primary AML samples the level of expression of total STAT3 and phospho-STAT1, 5 and 6 were all significantly higher (P <0.0004) in the CD34+/CD38− compartment compared to the other populations, supporting the concept that STAT activation is relevant to leukemic stem cell biology [36].