Results of cross platform validation of the cell type comparison.

Based on the Affymetrix data, the 200 genes whose expression was the highest in endothelial cells compared to neurons (AFFY_ENDO), and the 200 genes whose expression was the highest in neurons compared to endothelial cells (AFFY_NEURON) were used to create categories. These Affymetrix-derived categories were then investigated in the ranked gene list (endothelial cells vs neurons) generated using the Codelink platform. A positive enrichment score indicates enrichment in endothelial cells, and a negative score indicates enrichment in neurons. The categories were all found to be significantly enriched in the predicted direction in the Codelink data (q<0.25). The converse procedure was carried out testing categories generated from the Codelink data (CL_ENDO, CL_NEURON) on the Affymetrix platform, with comparable results.