FOXO1 and alveolar rhabdomyosarcoma: Others demonstrated that small molecule inhibitors of GSK3β affect the proliferation and viability of ARMS tumor cells.19 We determined that GSK3β phosphorylates PAX3-FOXO1 at Ser201 in primary myoblasts and in ARMS cell lines.16 However, no studies correlated the inhibition of GSK3β with a decrease in phosphorylation at Ser201 or how these changes affect ARMS tumor phenotypes.