Multidimensional scaling plot of expression profiles from patients with ALL. Bone marrow samples from patients with ALL are each represented by a sphere. The color of the spheres corresponds to the indicated molecular abnormalities. The high dimensionality of the gene expression data has been reduced to the 3 dimensions that comprise the greatest variation across the dataset. In the top panel, the 3 component dimensions separate cases of T-ALL, E2A-PBX1, TEL-AML1, and hyperdiploid of more than 50 chromosomes from remaining ALL cases. In the bottom panel, 3 different component dimensions discriminate cases with the BCR-ABL translocation, MLL gene rearrangement, and a novel subgroup. Reprinted from Yeoh et al²²  with permission.