Small-molecule epidermal growth factor receptor tyrosine kinase inhibitors

The growth and proliferation of cells are usually tightly regulated processes that are activated by stimuli from their environment. Epidermal growth factor (EGF)-related peptides represent a class of molecules that can trigger cell proliferation, among several cellular processes, such as differentiation, migration, and survival. Binding of EGF-like peptides to the EGF receptor (EGFR) at the cell surface leads to a cascade of intracellular reactions that transduce signals to the nucleus, resulting in particular gene expression patterns. However, in many tumor cells, the regulation of EGFR activity is lost, due to increased or aberrant expression of the receptor or its ligands, and this contributes to many processes important for tumor growth, including cell proliferation, survival, angiogenesis, invasion, and metastasis. Many strategies have been developed that specifically target the EGFR and inhibit its activity. Of these, small-molecule tyrosine kinase inhibitors represent one of the most promising classes of anticancer agents. Here, we describe the status of small-molecule EGFR tyrosine kinase inhibitors in preclinical and clinical development.