Taken together, these results suggest that differently from AML-M3, where HIF-1α specifically cooperates with the fusion protein PML-RARα, in AML-M5 HIF-1α may regulate the expression of a set of genes that are specifically expressed in monocytic progenitors, independently from the genetic insult that led to their oncogenic transformation. The gene discussed is RARA; the disease is acute myeloid leukemia.