For the pathways inflammation, oxidative stress and lung cancer, the following regulated genes were investigated regarding their protein expression in either BAL or lung tissue of CeO2 and BaSO4 exposed animals: Ccl2, Ccl20, Il-1α and Il-1ß (BAL analysis), Lpo and Mmp12 (immunohistochemistry of lung tissue). The gene discussed is LPO; the disease is lung carcinoma.