Synovial sarcoma is a form of cancer occurring most commonly in the limbs of young adults. Patients are treated with aggressive surgery and radiation, but the disease often spreads and proves fatal. Current chemotherapy provides limited benefit, with serious side effects. Using gene microarrays, a new technology that allows scientists to monitor tens of thousands of genes simultaneously in tumour specimens, Dr. Nielsen helped discover a group of genes playing a central role in synovial sarcoma. These include several potential therapeutic targets, including the signalling pathway involving retinoic acid, a vitamin A derivative. Several existing and experimental drugs interfere with this pathway and have been successfully used to treat other cancers such as leukemia, but have not been tested in synovial sarcoma. Dr. Torsten Nielsen is using the gene expression profile of this cancer type to develop targeted therapies needed for its treatment.