In the treatment of HER-2 over-expressing breast cancer, which drug is used to target erb-B2?

Trastuzumab is a monoclonal antibody specifically designed to target the human epidermal growth factor receptor 2 (HER2), which is also known as erb-B2. In certain breast cancers, HER2 is overexpressed, leading to more aggressive tumor behavior. Trastuzumab works by binding to the extracellular domain of the HER2 protein, inhibiting its signaling pathways. This action not only helps prevent the proliferation of HER2-positive cancer cells but also marks these cells for destruction by the immune system.

In addition to blocking the receptor itself, trastuzumab also has a mechanism that includes antibody-dependent cellular cytotoxicity (ADCC), where immune effector cells are recruited to attack cells that express the HER2 antigen. Because of its targeted action against HER2, trastuzumab is a crucial component of treatment regimens for patients with HER2-positive breast cancer and has significantly improved outcomes for these patients.

The other options listed do not target HER2; they are monoclonal antibodies directed against different targets or cytokines involved in other conditions.