Distinction between immature and cortical T-ALL samples. Analysis of 32 T-ALL samples based on a supervised identification of differentially expressed genes between 12 immature T-ALL samples and 20 cortical T-ALL samples. Labels and coloring of the classes were added after analysis for better visualization. (A) In hierarchical cluster analysis, the normalized expression value for each gene (given in rows) is coded by color (SD from mean). Red cells indicate high expression, and green cells indicate low expression. (B) In 3-dimensional PCA, T-ALL samples were projected into the feature space consisting of the top 100 differentially expressed genes when comparing patients with immature (orange) and cortical (purple) T-ALL. Data points with similar characteristics cluster together. A single color-coded sphere represents each patient's expression pattern.