CD33 and chronic myelogenous leukemia, BCR-ABL1 positive: The KBM5 cells used in this present study derive from a CML patient in myeloid blast crisis (> 20% immature blasts), and we have shown by flow cytometry that these cells express the surface markers CD33 (a pan-myeloid marker) and CD15 (a marker expressed on granulocytes and monocytes) (Figure 3B).