This is an image of a mouse lung tumor, after the mouse has been treated with an inhibitor for a protein that we think may play an important role in lung cancer. This is a zoomed-in view with an outer edge of dense live cells surrounding a complex core that includes dying cells in the less dense pink areas, and holes where dead cells have been cleared away. This zone is also infiltrated by extracellular matrix, which provides structure and stains blue. The extracellular matrix is not normally found in proliferating zones of a tumor. While there is some abnormal extracellular matrix deposition, the most striking point of this image is that the drug is promoting some clearance in the center of this tumor because without clearance the tumor mass will persist even if some cells are dying.