Keywords: Cancerous lung.jpg Public domain image from cancer gov http //visualsonline cancer gov/details cfm imageid 2348 Cross section of a human lung The white area in the upper lobe is cancer the black areas indicate the patient was a smoker PD-USGov In addition to the implicit public domain status provided as a work of the United States Government the National Cancer Institute has also explicitly licensed this photo into the public domain http //visualsonline cancer gov/about cfm Gross pathology of lung cancers |