FOXO1 and cancer: For instance, FOXO1 gene is fused to PAX3 or PAX7 genes in rhabdomyosarcoma, and FOXO3 or FOXO4 gene is fused with MLL gene, thereby causing hematological malignancies.[10] Also constitutively active FOXO1 or FOXO3a inhibits endothelial cell migration and tube formation in vitro, but FOXO4 cannot do so.[11] Here, we focus on FOXO4, a member deregulated in many types of cancer.