We found that inhibiting the phosphorylation of PAX3-FOXO1 at Ser201 significantly reduced migration, invasion and proliferation in two independent ARMS tumor cell lines.    ///    "We found that inhibiting the phosphorylation of PAX3-FOXO1 at Ser201 significantly reduced migration, invasion and proliferation in two independent ARMS tumor cell lines. "    ///    Inhibiting phosphorylation of the oncogenic PAX3-FOXO1 reduces alveolar rhabdomyosarcoma phenotypes identifying novel therapy options..     ///    "These results identify phosphorylation of PAX3-FOXO1, especially at Ser201, as a novel biological target that can be explored as a promising avenue for ARMS therapies. "    ///    "Along these lines, we demonstrated that PAX3-FOXO1 is phosphorylated at three specific sites and that its pattern of phosphorylation is altered relative to wild-type Pax3 throughout early myogenesis and in ARMS tumor cells. "    ///    "Consistent with these in vitro results, we demonstrate for the first time that PAX3-FOXO1 is phosphorylated at Ser201 and Ser205 in a primary tumor sample and in tumor cells actively invading the surrounding normal tissue. "    ///    This report is the first to demonstrate that the direct inhibition of PAX3-FOXO1 phosphorylation reduces ARMS tumor phenotypes in vitro and that these phosphorylation events are present in primary human ARMS tumors and invading tumor cells.     ///    " Patients with translocation-positive alveolar rhabdomyosarcoma (ARMS), an aggressive childhood tumor primarily characterized by the PAX3-FOXO1 oncogenic fusion protein, have a poor prognosis because of lack of therapies that specifically target ARMS tumors. "    ///    "To address this gap in knowledge, we used small molecule inhibitors or mutational analysis to specifically inhibit phosphorylation of PAX3-FOXO1 to investigate how altering phosphorylation of the oncogenic fusion protein affects ARMS phenotypes."    ///    "To address this gap in knowledge, we used small molecule inhibitors or mutational analysis to specifically inhibit phosphorylation of PAX3-FOXO1 to investigate how altering phosphorylation of the oncogenic fusion protein affects ARMS phenotypes. "