CD34 and acute lymphoblastic leukemia: For instance, immunocompromised mice transplanted with human CD34+ cells which were transduced with the MLL-AF9 fusion protein, a primary translocation event t(9;11) (p22; q23) commonly observed in leukaemias, were shown to develop into different types of leukaemia: acute myeloid leukaemia (AML), acute lymphocytic leukaemia (ALL), or biphenotypic leukaemia depending on the cytokines in the culture medium.