FLT3 and acute myeloid leukemia: While it has been reported that Flt3L may cause lymphoproliferative malignancies with the described mutations of Flt3 in AML, no clinical trial has confirmed this issue when flt3L has been administered to patients.28 The use of retroviral vectors expressing Flt3L has shown the stimulation of the immune system in some AML murine models29 despite the fact that it is a controversial therapy.