FOXO4 and rhabdomyosarcoma: In humans, there are three functional DAF-16 orthologs (in the following referred to as “FoxOs”), which are widely expressed and show redundant activities: FoxO1 (alternatively known as forkhead in rhabdomyosarcoma), FoxO3 (also known as forkhead in rhabdomyosarcoma-like 1), and FoxO4 (also known as acute lymphocytic leukemia 1-fused gene from X-chromosome) (2, 5).