With roughly 80% of cancer patients receiving their oncology care in the community setting, the investigators are proposing to sample from a community-based center to evaluate the percentage of epidermal growth factor receptor (EGFR)-wild type patients that gain benefit from erlotinib and assess the clinical characteristics that are associated with erlotinib-responders. Additionally, biopsy specimens from enrolled patient cases that are EGFR-wt will be evaluated via exploratory genetic analysis for correlated markers.