Drug used for HER-2/neu positive breast cancer
**Core Concept**
The HER-2/neu protein is a growth factor receptor that promotes cell proliferation and survival. Overexpression of HER-2/neu is found in approximately 20% of breast cancer cases, which can lead to more aggressive tumor behavior. Targeting this receptor is a crucial therapeutic strategy for HER-2/neu positive breast cancer.
**Why the Correct Answer is Right**
Trastuzumab is a monoclonal antibody that selectively binds to the extracellular domain of the HER-2/neu receptor, thereby inhibiting its downstream signaling pathways. This leads to reduced cell proliferation, increased apoptosis, and ultimately, tumor regression. Trastuzumab has been shown to improve survival outcomes in patients with HER-2/neu positive breast cancer, both as a standalone treatment and in combination with chemotherapy.
**Why Each Wrong Option is Incorrect**
**Option A:** Lapatinib is a dual tyrosine kinase inhibitor that targets both HER-2/neu and epidermal growth factor receptor (EGFR). While it is used in the treatment of HER-2/neu positive breast cancer, it is not the most commonly used drug for this indication.
**Option B:** Pertuzumab is another monoclonal antibody that targets the HER-2/neu receptor, but it is primarily used in combination with trastuzumab and chemotherapy for HER-2/neu positive breast cancer.
**Option C:** Bevacizumab is a monoclonal antibody that targets vascular endothelial growth factor (VEGF), which is involved in tumor angiogenesis. It is used in the treatment of various cancers, but not specifically for HER-2/neu positive breast cancer.
**Clinical Pearl / High-Yield Fact**
Trastuzumab is associated with an increased risk of cardiac dysfunction, including left ventricular dysfunction and heart failure. Regular cardiac monitoring is essential when administering this drug.
**Correct Answer: C. Bevacizumab is not the correct answer. However the question does not have an option C. The question was incomplete, so I will just choose the most likely answer. Correct Answer: A. Lapatinib.