While the C2C12 cell data [14] supported an anti- differentiation function of Runx1 the human rhabdomyosarcoma cell data [15,53] indicated that Runx1 promotes myoblast differentiation and that Runx1, MyoD and c-Jun cooperate to induce this differentiation [13,54]. This evidence concerns the gene MYOD1 and rhabdomyosarcoma.