FLT3 and acute myeloid leukemia: Further proof that MTSS1 expression is differentially regulated by oncogenic alterations in AML cells came from the fact that MTSS1 mRNA levels were significantly higher in an AML cell line carrying the t(8;21) translocation (Kasumi-1) than in FLT3-ITD positive cells (MV4-11), PML-RARα t(15;17) positive cells (NB4) or U937 cells (Fig 1C).