Differential in Gel Electrophoresis (2d dige proteomics) is a technique to monitor the differences in proteomic profile between cells in different functional states. This is done in three steps. First, samples are tagged with unique fluorescent dyes. Second, they are run together on the same 2D-PAGE gel. Finally, after the run completes, the different fluorescent images of the same gel are superimposed over each other. DIGE allows the study of proteins that are expressed differentially, as well as those that are common between samples. This technology allows for simultaneous separation and comparison of up to three samples on one gel.