HER2-BsAb also mediated potent ADTC against most of the osteosarcoma cell lines which were HER2-positive (143B, U-2 OS, MG-63, HOS, and Saos-2) and against hFOB1.19, with maximal cytotoxicity at 5 to 500 pM. The gene discussed is ERBB2; the disease is osteosarcoma.