ABL1 and precursor B-cell acute lymphoblastic leukemia: While studies in larger cohorts are required to comprehensively study potential correlations, the lack of a clear association of FLT3 expression with the prevalence of other therapeutic targets like CD19, CD20, CD22, BCR-ABL and the high binding capacity of antibody clone 4G8 in our view substantiate the value of FLT3 targeting by 4G8-SDIE for treatment of B-ALL.