Although it is rarely tested in acute leukemia (Noronha et al., 2016; Paietta et al., 2004) a few studies have found that the CD135 antigen is highly expressed in B-cell ALL, in B-cell lines, in AML, and to a lesser degree in T-cell ALL (Drexler, 1996; Noronha et al., 2016; Wells et al., 1996). This evidence concerns the gene FLT3 and acute leukemia.