PAX7 and alveolar rhabdomyosarcoma: These findings of MYOD1 upregulation are in accord with results reported in previous studies of MYOD1 expression in human ARMS (26,27), PAX3/PAX7-FOXO1-positive cells (13), mesenchymal stem cells transfected with PAX3-FOXO1 (28), and NIH3T3 fibroblasts transduced with PAX3-FOXO1 (10,29).