Final answer:
Trastuzumab, or Herceptin, is the chemotherapy drug used as adjuvant therapy for HER2/neu overexpressing breast cancers, targeting the HER2 receptor and increasing patient survival rates.
Step-by-step explanation:
The chemotherapy drug used for adjuvant therapy for HER2/neu breast cancers is trastuzumab. HER2/neu is a cell-surface receptor that, when overexpressed, contributes to the development of certain breast cancers. Trastuzumab, also known as Herceptin, is a monoclonal antibody that targets the HER2 receptor, which is present in excessive amounts in 20 percent of human breast cancers. It helps control signaling through HER2 and has been shown to increase the overall survival rate of patients with metastatic breast cancer when used in combination with chemotherapy. Trastuzumab, also known as Herceptin, is a monoclonal antibody that specifically targets the HER2 receptor for removal by the immune system, thereby helping to control cell signaling through HER2. This targeted therapy, when used in combination with other chemotherapy drugs, has significantly increased the overall survival rate of patients with metastatic breast cancer.