FLT1 and acute leukemia: One important underlying mechanism of AML is the increased microvessel density and elevated VEGF and KDR expression levels (Rashika et al., 2016; Lin et al., 2019) Since VEGF exerts its effects mainly through two high-affinity tyrosine kinase receptors, VEGF receptor 1 (VEGFR1) and VEGFR2, the expression level of VEGF receptor in acute leukemia is a prognostic factor that correlates with disease progression and patient overall survival (Torres Sánchez et al., 2009; Wang et al., 2015).