18029 Background: Erlotinib, a tyrosine kinase inhibitor, has improved survival and quality of life in patients with non-small cell lung cancer (NSCLC) after fist-line or second-line chemotherapy. Asian origin, adenocarcinoma histology, female gender, lack of tobacco use and expression of EGFR are significant independent predictors of response to erlotinib. Although tobacco use is considered a major cause of NSCLC, other factors are involved in its pathogenesis. In underdeveloped countries such as Mexico, wood and other solid fuels are still used for cooking and heating. The physiopathological mechanisms of wood smoke exposure (WSE) as a potential risk factor for the development of NSCLC are still unknown. Methods: 125 patients with the diagnosis of NSCLC with poor performance status and after first or second-line chemotherapy were treated with erlotinib. Clinical and pathological characteristics were associated with response. Results: We found a global response to erlotinib in 39 patients (31.2%; IC 95% ...