When to screen and not to screen

Colorectal cancer (CRC) is the third most common cause of cancer-related deaths with treatment of advanced and metastatic CRC (mCRC) remaining palliative at best. (1) The epidermal growth factor receptor (EGFR) has been identified as a therapeutic target for a multitude of malignancies, including mCRC. Ligand-binding to EGFR results in the subsequent activation of multiple signal transduction pathways including the PI3K/AKT and RAS/RAF/MAPK pathways, which are vital for cell growth and survival. (2) Constitutive activation of these signaling pathways leads to deregulated cellular proliferation, malignant progression, and invasion. (3.)