 PAX3-FKHR is a fusion oncoprotein generated by the 2;13 chromosomal translocation in alveolar rhabdomyosarcoma (ARMS), a cancer associated with the skeletal muscle lineage.     ///    "Although PAX3-FKHR alone failed to exert transforming activity, a combination of PAX3-FKHR and MYCN induced transforming activity in cell culture assays. "    ///    "Furthermore, myoblasts expressing PAX3-FKHR with or without MYCN formed tumors in SCID mice. "    ///    Comparisons of tumor and parental cells revealed that only a subset of parental cells developed into tumors and that tumor cells expressed high PAX3-FKHR levels compared with transduced parental cells.     ///    High expression of the PAX3-FKHR oncoprotein is required to promote tumorigenesis of human myoblasts..     ///    "To investigate the relationship between expression and phenotype in human myogenic cells, PAX3-FKHR was introduced into immortalized human myoblasts to produce a low overall PAX3-FKHR expression level. "    ///    Previous studies determined that high-level PAX3-FKHR expression is a consistent feature in ARMS tumors.     ///    "however, most subclones expressed low PAX3-FKHR and showed neither transforming nor tumorigenic activity. "    ///    "Finally, RNA interference experiments in myoblast-derived tumor and ARMS cells revealed that high PAX3-FKHR expression plays a crucial role in regulating proliferation, transformation, and differentiation. "