Figure 2

PCA of protein profiles. PCA projection of protein profiles obtained by 2-DE in a scatter plot using the entire data set (A) and the data set after subtracting data points corresponding to proteins common for in vitro cell cultures (B). In panel A, PC1 and PC2 explain 37.3% and 13.8% of the total variation, respectively. In panel B, PC1 and PC2 explain 24.9% and 17.4% of the total variation, respectively. Open symbols and closed symbols represent 2-D profiles of cell lines and epithelial scrapings, respectively, as shown in panel A. The cluster numbers containing proteins which are mainly responsible for separation between groups are depicted next to the arrows in panel A. SI, small intestine; LI, large intestine; EC, epithelial cells.