If you took apart a tumor, what would you find inside? There would be cancer cells, of course, but scientists are increasingly aware that a wide variety of “healthy” cells also reside in tumors and contribute to cancer progression. Here, MIT researchers have removed two cell types from a lung tumor: cancer cells (smaller) and fibroblasts (larger), which normally help to heal wounds in the body. By mapping out exactly what these non-cancerous cells are doing inside tumors and how they interact with cancer cells, the researchers hope to identify new ways of targeting and treating lung cancer.