EGFR and colorectal cancer: The aberrant activation of the epidermal growth factor receptor (EGFR), a member of the HER/ErbB family of receptor tyrosine kinases (RTKs), by its overexpression or mutations is a major mechanism underlying the development and progression of human malignant tumors, including colorectal cancer, lung cancer, and glioblastoma multiforme (GBM)1–4.