Interestingly, MLL–Af4 transformed myeloid cells cultured in a myelopoietic condition had increased expression of lymphoid regulators, such as Ebf1, compared to AML cells transformed by MLL–AF9, suggesting that the myelopoietic condition cannot fully rewire the lymphoid program imposed by MLL–Af4. Here, AFF1 is linked to acute myeloid leukemia.