Figure 1

Gene expression profiling of meningiomas. A) Unsupervised hierarchical clustering of expression data derived from 23 primary meningioma tumors of the three histopathological grades was performed. Each column represents one case and each row represents the expression value of an individual probeset. Expression values are color coded as follows: higher (red), lower (green) or close (black) to the median expression value of each probeset. Tumor case numbers are listed above each column and are color-coded by histopathological grade. Red, Grade 1; Green, Grade 2; and Blue, Grade 3. The classification tree on top suggests two major molecular subgroups of meningiomas. The asterisk refers to the Grade 2 meningioma with a unique expression pattern. B) Principal component analysis of the meningioma expression profiles. Distribution of the 23 primary meningioma tumors along the three calculated principal components, PC1, PC2 and PC3. Tumor cases are color coded by histopathological grade. Red, Grade 1; Green, Grade 2; and Blue, Grade 3.