Abstract
Epidermal growth factor receptor (EGFR) is a major molecular for target therapy. The epidermal growth factor receptor tyrosine kinase inhibitors (TKIs), gefitinib (Iressa) and erlotinib (Tarceva), are two prospective agents towards non-small cell lung cancer (NSCLC). Multi-center clinical studies showed that there were obvious differences between individuals by the treatment of EGFR-TKIs. EGFR status is the major factor that influences the outcome for the treatment by TKI. Exon mutations and amplification of EGFR molecule are the critical factors that predict good response to TKIs. On the other hand, KRAS mutations indicate the resistant to the TKIs.