This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology and breast, Subject name: Surgery
[{'content': 'Trastuzumab is directed against \nSelect and explain. \nA. Human epidermal growth factor receptor 2, B. Vascular endothelial growth factor A, C. Platelet derived growth factor, D. Fibroblast growth factor 23', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Trastuzumab is a humanized monoclonal antibody directed against the extracellular domain of the (human epidermal growth factor receptor -2) HER-2 surface receptor and is effective treatment for HER-2-positive breast cancer Ref: Sabiston 20e, page: 840', 'role': 'assistant'}]