Synthetic gel created by merging features from 2D gel of 8701-BC cells with that from DIC biopsy (available by internet at http://www.bio-mol.unisi.it/2d/2d.html and reported in reference 12). The number of features detected within the analysis window were 1811 in the cell map and 2602 in the DIC map. The gel matching resulted on 1116 pairs of features, corresponding respectively to a percentage of cross-overlapping of about 62% (cell/DIC) and of 42% (DIC/cell). The feature labels on the synthetic gel bear the same numbers as in figure 2, and correspond to spots common to the two original gels. Clusters of corresponding spots are surrounded by contours.