In BALB-p53Neu rhabdomyosarcoma, as well as in human rhabdomyosarcoma [16,23], IGF1R-dependence also contributes to tumor growth, as proven by the expression of IGF1R and concomitant autocrine production of IGF2 [22], and by the growth inhibition obtained with anti-IGF1R targeted antibodies [15], small inhibitors, and siRNA or IGF2-directed immune targeting [24]. Here, IGF1R is linked to rhabdomyosarcoma.