Nur77, a transcription factor belonging to a superfamily of orphan nuclear receptors, has been shown to activate a subset of genes containing NGFI-B response element (NBRE). Nur77 expression is upregulated in response to stimuli of numerous growth factors, mitogens, and inflammatory substances, indicating that Nur77 has regulatory roles in cell growth and inflammation. Nur77 has also been shown to participate in programmed cell death through mitochondrial targeting and interaction with Bcl-2. In the endocrine system, Nur77 has been reported to participate in regulating production of steroidogenic enzymes. Nur77 and NOR-1 double knockout mice develop acute myeloid leukemia, suggesting that Nur77 plays a role in regulating differentiation of myeloid progenitor cells.