FOXO1 and alveolar rhabdomyosarcoma: In the present study, to better characterize the oncogenic role of the PAX3-FOXO1 fusion protein in the acquisition of aggressive behavior in ARMS, we conducted proteomic studies using a PAX3-FOXO1 knockdown system in ARMS cell lines and in vitro assays, and found that among the protein list, proteins encoded by PPP2R1A were downregulated in the native ARMS cell lines.