Which pharmacologic therapy is specifically indicated for HER2-positive breast cancer?

Which pharmacologic therapy is specifically indicated for HER2-positive breast cancer?

• A. Tamoxifen
• B. Letrozole
• C. Trastuzumab (Herceptin)
• D. Anastrozole

Answer: (C)

Targeted therapy against the HER2 receptor is used in breast cancers that overexpress HER2. When tumor cells have amplified or overexpress HER2, the receptor drives aggressive growth through its signaling pathways. Trastuzumab is a monoclonal antibody that binds the HER2 protein on the surface of these cancer cells, blocking the receptor’s signaling and flagging the cells for immune attack. This targeted action can slow or halt tumor growth and, when combined with chemotherapy, improves disease outcomes in both early-stage and advanced disease. In contrast, the other therapies mentioned work on hormone pathways rather than HER2. Tamoxifen blocks estrogen receptors, useful in estrogen receptor–positive cancers. Aromatase inhibitors like letrozole and anastrozole reduce estrogen production in postmenopausal patients, also for ER-positive tumors. Because they do not target HER2 signaling, they aren’t specifically indicated for HER2-positive breast cancer.

Targeted therapy against the HER2 receptor is used in breast cancers that overexpress HER2. When tumor cells have amplified or overexpress HER2, the receptor drives aggressive growth through its signaling pathways. Trastuzumab is a monoclonal antibody that binds the HER2 protein on the surface of these cancer cells, blocking the receptor’s signaling and flagging the cells for immune attack. This targeted action can slow or halt tumor growth and, when combined with chemotherapy, improves disease outcomes in both early-stage and advanced disease.

In contrast, the other therapies mentioned work on hormone pathways rather than HER2. Tamoxifen blocks estrogen receptors, useful in estrogen receptor–positive cancers. Aromatase inhibitors like letrozole and anastrozole reduce estrogen production in postmenopausal patients, also for ER-positive tumors. Because they do not target HER2 signaling, they aren’t specifically indicated for HER2-positive breast cancer.