Although the efficacy of trastuzumab cannot be evaluated in a randomized controlled trial since the study did not directly compare the efficacy of trastuzumab with or without trastuzumab in HER2-positive patients, the results of the Children’s Oncology Group study did not indicate that trastuzumab would be effective for the treatment of HER2-positive osteosarcoma. This evidence concerns the gene ERBB2 and osteosarcoma.