Phenotypic characteristics of MLL-AF4, MLL-AF9, and MLL-ENL ALL cells. (A-C) Representative flow cytometry plots showing expression of CD34, CD38, CD19, and CD33 in cells derived from infant ALL patients with (A) MLL-AF4, (B) MLL-AF9, and (C) MLL-ENL translocations. Morphology of leukemic cells derived from representative cases is shown. (D) Frequencies of CD34⁺CD38⁻, CD34⁺CD38⁺, and CD34⁻ cells in MLL-rearranged infant leukemia (MLL-AF4, n = 14; MLL-AF9, n = 7; MLL-ENL, n = 7).