The American Society of Clinical Oncology (ASCO) today issued a provisional clinical opinion (PCO) on the clinical use of epidermal growth factor receptor (EGFR) mutation testing to identify patients with advanced lung cancer who may benefit from targeted agents known as EGFR tyrosine kinase inhibitors. These treatments include gefitinib (Iressa) and erlotinib (Tarceva). The PCO, which is based on the results of five recent randomized clinical trials, recommends that patients with advanced non-small cell lung cancer who are being considered for first-line therapy with an EGFR tyrosine kinase inhibitor (meaning the patient has not previously been treated with chemotherapy or other anti-cancer drugs) should first have their tumor tested for EGFR mutations. Such testing is currently available, both at academic medical centers and at some community medical centers.