- Molecular characterization of non-squamous non-small cell lung cancer will be recommended prior to enrollment per standard of care/institutional guidelines; consistent with current National Comprehensive Cancer Network (NCCN) guidelines and the recent Food and Drug Administration (FDA)-approval indication of erlotinib for first-line treatment of advanced non-small cell lung cancer in persons with tumor EGFR mutations, participants who have known EGFR sensitizing mutations in tumors will be permitted to enter the study and receive erlotinib as initial monotherapy; for participants who have received one or more prior lines of chemotherapy, molecular characterization of tumors is required whenever possible with an understanding that inability to obtain sufficient tissue specimen for characterization will not preclude enrollment into the study