RHD and rhabdomyosarcoma: Similar to our observations made in EwS (Fig. 1b), we found a significant induction of reporter gene expression in fusion-positive ARMS (RH4 and RH30) but not in fusion-negative embryonal rhabdomyosarcoma (RD) or in non-rhabdomyosarcoma control cell lines (U2-OS, HeLa, Jurkat and A-673) (Fig. 3a).