The free GeneXPress software available from this site can help researchers parse microarray data to identify groups of genes that work in concert during normal activities or in cancerous cells. Created by researchers at Stanford University, the program winkles out clusters of genes whose activity rises or falls in unison. The site also holds a database of results from the group's analysis of nearly 2000 microarrays for 22 tumor types from published studies. As they reported in this month's Nature Genetics, the researchers found 456 “modules,” or gene teams that labor together. A cadre of genes that checks division shuts down in cells from some leukemia patients, for example.