The PAX3:FOXO1 fusion gene, arising from the t(2;13)(q35;q14) translocation [27] in the paediatric soft tissue tumour alveolar rhabdomyosarcoma (ARMS), encodes a transcription factor that contains the PAX3 (paired box 3) DNA-binding domain and the FOXO1 (forkhead box O1) transactivation domain. The gene discussed is FOXO1; the disease is alveolar rhabdomyosarcoma.