What is Herceptin's primary mechanism of action?

Herceptin, also known as trastuzumab, primarily functions by binding to the HER2 (human epidermal growth factor receptor 2) receptors on the surface of cancer cells. HER2 is a protein that, when overexpressed, is associated with aggressive forms of breast cancer and poorer prognosis. By attaching to these receptors, Herceptin effectively blocks the signaling pathways that would otherwise stimulate cell division and proliferation. This inhibition of HER2 signaling can slow down or even stop the growth of tumors that rely on this pathway for their advancement.

The action of Herceptin is particularly significant in treatments for HER2-positive breast cancer, where the overactivity of this receptor contributes to the malignancy. Blocking these receptors not only hampers tumor growth directly but can also instigate other systemic immune responses that promote the destruction of cancer cells.

Thus, the primary mechanism of action of Herceptin centers around its ability to bind to and inhibit HER2 receptors, blocking their signaling pathways and thereby reducing tumor growth and progression.