By analyzing the genes that are active in tumor cells, scientists may be able to predict whether the most common form of liver cancer, hepatocellular carcinoma, is likely to spread from its original site. Researchers at the National Cancer Institute (NCI), in collaboration with surgeons at the Liver Cancer Institute of Fudan University in Shanghai, report in a study published in Nature Medicine* that they have identified a pattern of gene activity that is unique to hepatocellular carcinoma cells that spread, or metastasize. Knowing whether a tumor is likely to metastasize can help physicians decide on the best treatment strategy for a patient.