ID1 and myeloproliferative disorder: Finally, mice transplanted with Id1-overexpressing HSPCs become moribund within a year after transplantation and develop a myeloid proliferative neoplasia (MPN) including 1) increased myeloid blasts in BM, 2) splenomegaly and extramedullary hematopoiesis (myeloid and erythroid), and 3) myeloid cell infiltration in liver, which does not progress to acute myeloid leukemia (AML) (39).