Unsupervised cluster analysis of pediatric AMLs. Expression profiles of the diagnostic leukemic blasts from 130 cases of pediatric AML were obtained using the U133A Affymetrix microarray. The expression data were then filtered to remove any probe sets that failed to show significant variation in expression across the data set. The remaining 17 051 probe sets were then used in an unsupervised 2-dimensional hierarchical clustering algorithm, and the resultant dendrogram is shown. Indicated below the dendrogram are the genetic subtype and FAB morphology for each case according to the indicated color codes.