FLT3 and acute myeloid leukemia: Consequently, MMP9, which plays an important role in degradation of the extracellular matrix and OC precursor recruitment [13,15], and stromal cell-derived factor-1 (SDF-1, encoded by CXCL12), which acts as a key factor in the HSC niche [50], are downregulated in FLT3 ITD AML.