IGF1R and rhabdomyosarcoma: Using the Dock-and-Lock (DNL) platform [44], [45] to generate a hexavalent antibody, designated Hex-hR1, from its bivalent parent, hR1, a novel humanized antibody (IgG1, kappa) that targets IGF-1R, but not IR, we explored the opportunity of comparing the various biological activities exhibited by Hex-hR1 and hR1 in diverse cancer cell lines, as well as their in vivo efficacy in a xenograft model of human rhabdomyosarcoma (RH-30) in nude mice, with or without the addition of rapamycin.