CD33 and acute lymphoblastic leukemia: COMBAT1 and COMBAT2 both showed significantly elevated expression of stem/myeloid‐associated surface antigens (CD34, HLA‐DR, CD13, and CD33) and genes (GATA2, KIT, CSF3R, etc.), which are linked to poor chemotherapy response and inferior survival in B‐ALL patients [34, 36, 37].