ICAT and its variations have become the gold standard for comparing global protein expression in many proteomics labs. But they may soon be rivaled by another strategy, recently published by Steven Gygi’s group at Harvard. Termed “Aqua” for absolute quantification, it promises to allow users to measure a small number of proteins — or their modification states — in large numbers of biological samples. Aqua assays are slated to be commercialized soon by Cell Signaling Technology, a company based in Beverly, Mass.