Reproducibility of grade-correlation in an independent data set. Modules or genes correlated with tumor grade were identified in the GSE2109 dataset using different methods and tested for reproducibility in the GSE2990 dataset. ICE, MCODE, and K-means are three module-based methods. Gene_1 and Gene_2 are based on individual genes. Gene_1 does not exclude the difference between microarray platforms used for the two datasets, while Gene_2 is based on common genes on the microarray platforms.