Description: Myogenin is a member of the MyoD family of myogenic basic helix-loop-helix transcription. MyoD family members are expressed exclusively in skeletal muscle and play a key role in activating myogenesis by binding to enhancer sequences of muscle-specific genes. Anti-Myogenin antibody labels the nuclei of myoblasts in developing muscle tissue, and is expressed in tumor cell nuclei of rhabdomyosarcoma and some leiomyosarcomas. Positive nuclear staining may occur in Wilm’s tumor. Negative in Ewing sarcomas.