STAT3 and acute myeloid leukemia: Because the phenotypic analysis by flow cytometry revealed that both PVTL-1 and PVTL-2 cells were positive for CD117 (c-Kit), we examined the expression and phosphorylation status of c-Kit in these cells as well as in HEL cells and its possible effect on STAT3 activation, which is known to mediate leukemogenesis downstream of aberrantly activated c-Kit in AML cells [28].