Recent Developments of Small Molecule EGFR Inhibitors Based on the Quinazoline Core Scaffolds

Progress in identifying and understanding the molecular and cellular causes of cancer has led to the discovery of anomalies that characterize cancer cells and that represent targets for the development of cancer therapeutics. One such target is the epidermal growth factor receptor (EGFR), a transmembrane protein that is frequently dysregulated in cancer cells and associated with the development, progression and aggressiveness of a number of malignancies. Inhibition of EGFR signaling has thus been identified as an attractive strategy in control of tumor proliferation, and over a decade of intense activity in the field has culminated in the discoveries and subsequent approvals of gefitinib and erlotinib for the treatment of non-small cell lung cancer. However, the drug's resistance to gefitinib and erlotinib has been clinically observed. Therefore, intensive efforts have been made in the discovery of novel potent and selective EGFR inhibitors. This review will focus on the developments of small molecule EGFR inhibitors based on the quinazoline core scaffolds in recent 5 years. Diverse EGFR inhibitors are classified as 4-anilinoquinazolines and 4-nonanilininoquinazolines, their biological data are described, and the structure-activity relationships (SARs) are discussed.