Targeting the epidermal growth factor receptor in the treatment of colorectal cancer: state of the art.

The epidermal growth factor receptor (EGFR) is an important mediator of normal cellular processes such as growth, survival, differentiation and morphogenesis. Disturbances in the EGFR pathway have been associated with the development and progression of malignancy, including cellular proliferation, angiogenesis, invasion/metastasis and anti-apoptosis, as well as with resistance to chemotherapy and/or radiation therapy. As a result, this is an excellent rationale for treatment with EGFR-specific therapeutic agents. These agents may be EGFR-targeted antibodies or small molecules that inactivate the receptor tyrosine kinase. While only cetuximab has received US FDA approval for the treatment of colorectal cancer, numerous agents are currently in development and in clinical trials and constitute an area of intensive, ongoing research.