What type of cancer is Herceptin (trastuzumab) primarily used to treat?

Herceptin (trastuzumab) is primarily utilized in the treatment of HER2-positive breast cancer, which is characterized by the overexpression of the HER2 (Human Epidermal growth factor Receptor 2) protein, encoded by the ERBB2 gene. This particular subtype of breast cancer tends to be more aggressive and has a poorer prognosis when compared to other types of breast cancer.

Trastuzumab works by targeting and binding to the HER2 protein on the surface of cancer cells, inhibiting their growth and survival. It is considered a targeted therapy, specifically designed to disrupt the signaling pathways that promote tumor growth in those breast cancers that overexpress HER2.

This emphasis on HER2 and ERBB2 positive breast cancer makes trastuzumab a crucial component of treatment plans for patients with this specific cancer type, improving outcomes significantly compared to other non-targeted therapies. In contrast, the other cancers listed do not typically involve HER2 or ERBB2 as a primary target for treatment, making trastuzumab ineffective for them.