What is the main action of Cetuximab?

Cetuximab primarily functions by targeting the epidermal growth factor receptor (EGFR). This monoclonal antibody binds to the extracellular domain of the EGFR, inhibiting its activation by natural ligands such as epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha). By blocking EGFR signaling, Cetuximab effectively hinder cell proliferation, induce apoptosis, and impair tumor growth and spread. This mechanism is particularly significant in specific cancers, such as colorectal cancer and head and neck squamous cell carcinoma, which often exhibit overexpression of EGFR.

The other options represent actions associated with different therapeutic agents or pathways. Blocking PD-1 receptors is a mechanism employed by other immunotherapeutics that modulate immune response, but it is not the action of Cetuximab. Targeting vascular endothelial growth factor (VEGF) is characteristic of agents that aim to inhibit angiogenesis in tumors, which is distinct from the action of Cetuximab. Lastly, stimulating bone marrow production of white blood cells relates to certain treatments aimed at addressing cytopenias caused by cancer therapies, rather than the direct antitumor action of Cetuximab.