ABSTRACT
This chapter reviews the status of the predictive biomarker research for the epidermal growth factor receptor (EGFR) inhibitors that are currently in clinical use for the treatment of non-small cell lung cancer (NSCLC). Lung cancer is the leading cause of cancer-related death and despite efforts to improve treatment options, the overall 5-year survival still remains poor at 15%. The T790M mutation, a threonine to methionine substitution at position 790 in the catalytic cleft of the EGFR tyrosine kinase domain, was identified from lung cancer biopsies from patients with acquired resistance to prior EGFR TKIs. Rare EGFR mutations account for approximately 10% of cases. Due to their rarity, and the fact that many clinical trials of EGFR TKIs have excluded patients with these mutations, much of the data regarding sensitivity to EGFR TKIs has been based on small series. Ligands which target the epidermal growth factor receptor family consist of three main groups. The first group binds specifically to EGFR and consists of EGF, transforming growth factor-a and amphiregulin.
