To test whether the exogenous production of NO has a role in leukemia transplantation and progression, we transplanted leukemic cells from two models of murine AML (MLL-AF9 and MLL-ENL) in Nos3-knockout (Nos3-KO) recipient mice and studied the status of the vasculature and disease progression. Here, MLLT1 is linked to acute myeloid leukemia.