Correlation of compendium samples to exemplar HPI and LPI transcriptional profiles based on different gene signature subsets. PCC values of sample profiles to exemplar HPI (x-axis) and LPI (y-axis) transcriptional profiles were plotted, and quadrants were defined with respect to (0.5, 0.5). LPI and HPI samples located in quadrants II and IV, respectively, were considered accurately classified. (A) Using all genes in the compendium. (B) Using Fisher's statistic-derived digital signature genes. (C) Using module map-derived digital signature genes. (D) Using z-test-derived analog signature genes.