 Alveolar rhabdomyosarcoma (ARMS) is an aggressive myogenic-type tumor and a gain-of-function disease, caused by misexpression of the PAX3-FKHR or PAX7-FKHR fusion oncoprotein from structurally rearranged chromosomes.     ///    "PAX3-FKHR misexpressed in terminally differentiating mouse myofibers can cause rhabdomyosarcoma at a low frequency, suggesting that skeletal muscle is an ARMS tissue of origin. "