Log2 transformed expression values calculated using the Robust Multichip Average (RMA) method. This method is described in Irizarry, RA, Hobbs, B, Collin, F, Beazer-Barclay, YD, Antonellis, KJ, Scherf, U, Speed, TP. Exploration, Normalization, and Summaries of High Density Oligonucleotide Array Probe Level Data. Biostatistics, in press. RMA estimates are based upon a robust average of background corrected perfect match probe signal intensities. Quantile normalization was performed according to B. M. Bolstad et al., Bioinformatics 19:185, 2003.