PAHs and Lung Cancer (IMAGE) University of Pennsylvania School of Medicine Caption Chemical intermediate causes formation of reactive oxygen species in second indirect pathway connecting polycyclic aromatic hydrocarbons to lung cancer. Credit Trevor Penning, PhD, University of Pennsylvania School of Medicine Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.