Researchers at Harvard Medical School have identified a pattern of gene activity that seems to predict whether cancer will return after it is first treated. The ominous pattern shows up in many common types of cancer, including lung, breast, prostate, and brain. What’s more, it may be detectable before the malignancy starts to spread. It’s too soon to call the finding a revolution, but “it has the potential to help us predict which tumors will or will not spread in individual patients,” says Sridhar Ramaswamy, one of the researchers. “Further down the research pathway, it could pave the way to drugs that control spreading.” Ramaswamy and his colleagues at the Dana-Farber Cancer Institute and the Whitehead/Massachusetts Institute of Technology Center for Genome Research compared the activity of genes in original, or primary, tumors with the activity in those that spread. They found a distinct pattern present in the latter but not the former. Out of 76 patients whose tumors were examined, 12 who showed the spreading fingerprint fared worse than the others.