Which therapy is commonly used for HER2+ breast cancer?

The most appropriate therapy for HER2+ breast cancer among the given options is pertuzumab. This drug is a monoclonal antibody that targets the HER2 protein, which is overexpressed in about 15-20% of breast cancer cases. By inhibiting HER2 signaling, pertuzumab works effectively in conjunction with other therapies like trastuzumab to enhance treatment outcomes and improve survival rates in patients with HER2+ breast cancer.

Other options, such as raloxifene, letrozole, and aromatase inhibitors, are primarily used for hormone receptor-positive breast cancers, particularly estrogen receptor-positive cases. These medications do not target the HER2 protein and are not suitable for treating HER2+ breast cancer specifically. Thus, they would not be effective for someone whose cancer is driven by HER2 overexpression. Pertuzumab's targeted mechanism directly addresses the pathology associated with HER2+, making it the correct choice for this type of breast cancer.