Figure 1: An overview of the experimental procedure for 2D-DIGE experiments with an internal control sample. A. The internal control and the individual sample are labeled with Cy3 and Cy5, respectively, mixed together, and separated by 2D-PAGE. After electrophoresis, the gel is laser-scanned, and the Cy3 and Cy5 images are obtained. The Cy5 image data are normalized with the Cy3 image data to compensate for any gel-to-gel variation. B. A typical gel image of the Cy3-labeled internal control sample. The spot numbers correspond to those in Figure 2 and Table 2. C. System reproducibility was evaluated by running the identical sample three times, and reproducibility was evaluated using a scattergram.