CGH array and MGMT promoter methylation assays in GBM samples. A) Unsupervised cluster analysis of CGH data from 8 primary GBMs. Each column represents one case and each row represents one BAC clone. We assigned values of 1, 0 and -1 for gain, no change and loss, respectively. Losses are in green and gains in red. P-values < 0.05. B) Ideogram showing MGMT promoter methylation.