BM samples from Mll^PTD/WT:Flt3^ITD/WT mice dying of AML are cytogenetically normal as are the age-matched, WT, and single-mutant controls. G-banded karyotype analysis of WT, single-mutant, and leukemic Mll^PTD/WT:Flt3^ITD/WT mice was conducted on whole BM samples.