“Supervised” hierarchical clustering and principal components analysis (PCA) discriminating chronic kidney disease (CKD) and hemodialysis (HD) treatment. (A) Patients are depicted as vertical columns, with red symbols indicating HD (n = 17) and green indicating CKD (n = 9) patients. 275 gene probe sets were used for hierarchical clustering. The relative level of gene expression is depicted from lowest (green) to highest (red) according to the scale shown at the bottom. Cluster A and B include the top statistically significant up-regulated and down-regulated genes in HD compared to CKD, respectively. (B) PCA plot using the 275 selected gene probe sets discriminating the two groups of patients.