CD5 and acute lymphoblastic leukemia: ETP-ALL is defined by an immunophenotype of sCD3-, CD7+, CD1a-, CD8-, CD5-/dim ( < 75%), and positive for one or more myeloid (CD11b, CD13, CD33, CD117) or stem cell (CD34, HLA-DR) antigens; expression of cytoplasmic CD3 is also often observed [3, 27, 28].