A relatively new approach to researching cancer involves looking at the actions of thousands of genes in cancer tumors. This technique just recently became possible because, using new applications of technology, researchers are able to make “diagnoses by database.” At Harvard Medical School, several teams of researchers have recently discovered new types of cancer or new ways to diagnose known cancers by analyzing what are called the “gene expression patterns” of thousands of genes in diseased cells. The researchers involved in this work include postdoc Arindam Bhattacharjee in the Dana-Farber lab of pathologist Matthew Meyerson, Harvard Medical School (HMS) assistant professor of pathology; pediatric oncologist Scott Armstrong in the Dana-Farber laboratory of Stanley Korsmeyer; Dana- Farber oncologist Margaret Shipp, an HMS associate professor; Children’s Hospital pediatric neurologist Scott Pomeroy, an HMS associate professor of neurology; Dana- Farber oncologist Sridhar Ramaswamy, an HMS instructor; Todd Golub, HMS assistant professor of pediatrics; and Eric Lander, director of the genome center at the Whitehead Institute of Biomedical Research and Massachusetts Institute of Technology.