Gene expression profiling analysis of NPM1-mutated AML (NK vs AK). Analysis based on the top-500 differentially expressed genes between AML cases NPM1c⁻ (unmutated NPM1) and NPM1c⁺ (mutated NPM1). The gene discovery process was restricted to AML with NK (ie, a supervised analysis was performed). (A) Hierarchical clustering heatmap also including 10 NPM1 mutated AML cases with other chromosomal aberrations (other). The similarity of the genes was computed by Euclidean distance, and then Ward method was used to cluster the gene expression profiles based on these measures. The normalized expression value for each probe set is coded by color (standard deviation from mean). Red cells indicate high expression and green cells indicate low expression. (B) Principal component analysis (PCA). The AML samples were plotted in a 3-dimensional space using the 3 principal components (PC) capturing most of the variance in the original dataset (PC1 = 34.0%, PC2 = 7.0%, PC3 = 5.2%). Each patient sample is represented by a single color-coded sphere.