Which of the following anti-cancer drug comes under the group of monoclonal antibodies?
**Core Concept**
Monoclonal antibodies are a class of targeted therapeutic agents that utilize the body's immune system to fight cancer cells. They are engineered to recognize and bind to specific tumor antigens or markers, inducing various mechanisms of action such as apoptosis, antibody-dependent cellular cytotoxicity, and complement-dependent cytotoxicity.
**Why the Correct Answer is Right**
Trastuzumab is a monoclonal antibody that targets the human epidermal growth factor receptor 2 (HER2) protein, which is overexpressed in certain breast cancer cells. Trastuzumab interferes with the HER2 receptor's interaction with its ligand, thereby inhibiting cell proliferation and inducing apoptosis in tumor cells. This targeted therapy has significantly improved the prognosis for patients with HER2-positive breast cancer.
**Why Each Wrong Option is Incorrect**
**Option A:** Cetuximab is a monoclonal antibody that targets the epidermal growth factor receptor (EGFR), but it is not the correct answer in this context.
**Option B:** Bevacizumab is a monoclonal antibody that targets vascular endothelial growth factor (VEGF), but it does not target the HER2 protein.
**Option C:** Rituximab is a monoclonal antibody that targets the CD20 antigen on B cells, but it is not used in the treatment of HER2-positive breast cancer.
**Clinical Pearl / High-Yield Fact**
Monoclonal antibodies like trastuzumab have revolutionized the treatment of cancer by providing targeted and effective therapies with fewer side effects. Their use has led to improved patient outcomes and increased survival rates in various malignancies.
**Correct Answer: C. Trastuzumab**