"Cancers are diverse, and that makes them extremely difficult to treat. What worked stunningly for one person might fail utterly for another. What worked for a tumor in the brain probably won't work on a cancer of the liver. Scientists are trying to outwit tumors by coming up with tailored treatments like the immunotherapy drug used to successfully treat former President Jimmy Carter."

"But it's very hard to figure out how to find the right drug for a specific patient. A paper published Friday in Nature Communications suggests one thing that might help is identifying the astonishing mix of cells inside a tumor. It's not just cancer in there."

"Tumors can swallow up cells around them and grow into composites of malignant and healthy tissue. As that happens, they seem to take on different properties that could make them more or less responsive to an immunotherapy drug like Pembrolizumab, the medication that Carter received, one that works by stimulating the immune system to attack tumors, researchers say."