PAX7 and alveolar rhabdomyosarcoma: ,11 Conversely, nearly 80% of ARMS tumors contain an oncogenic fusion gene consisting of the DNA binding domain of myogenic homeobox transcription factors, PAX3 or PAX7, and the transactivation domain of FOXO1, resulting in a PAX3::FOXO1 or PAX7::FOXO1 fusion gene.12