Most cancer deaths are caused not by the original or primary tumor but by the metastasizing of tumor cells to other organs. Until now, cancer specialists have viewed the development of metastasis as an essentially random and unpredictable event. But that notion is thrown into question with the new finding of a genetic “signature” –- a certain pattern of activity in a handful of genes –- in some solid tumors that appears to preordain them to spreading dangerously. This signature is present in the early stages of the cancer, well before there is any evidence of metastasis, say the researchers. “These results strongly support the idea that some primary tumors are pre-configured to metastasize, and that this propensity is detectable at the time of initial diagnosis,” says Sridhar Ramaswamy, a researcher at Dana-Farber Cancer Institute. If larger studies support these findings, this early indicator of life-threatening cancer spread might lead to a clinical test that would help determine appropriate treatment.