When cancer cells begin to do their destructive work, they have accomplices — normal cells that help nourish the cancerous ones. As Jack Lawler, Harvard Medical School associate professor of pathology at Beth Israel Deaconess, puts it, there are no innocent bystanders in the process. “Previous research focused on the genetics of the cancer cell,” Lawler said. “Now we have to think about the whole tissue and the various other cell types present.” Lawler and his colleagues, M. Luisa Iruela-Arispe from UCLA, Roderick Bronson of Tufts University and Harvard Medical School, and Richard Hynes from MIT, have addressed the interaction between cancer cells and their accomplices by studying the effects of thrombospondin-1 (TSP-1) on tumor growth and angiogenesis, which is the proliferation of blood vessels that feed growing tumors. The researchers hope their work will offer insights into how cancer cells recruit normal cells to do their terrible work. Blocking such interactions might lead to new therapies to battle cancer.