Distinction between c-ALL/pre–B-ALL with t(9;22) and CML. In 3-dimensional PCA, 117 samples were projected into the feature space consisting of a combination of the top 100 differentially expressed genes when comparing c-ALL/pre–B-ALL with t(9;22) samples with the other 12 classes and CML with the other 12 classes. Data points with similar characteristics will cluster together. A single color-coded sphere represents each patient's expression pattern. The respective label (pre–B-ALL or CML) was unknown to the algorithm. Labels and coloring of the classes were added after the analysis of means for better visualization. c-ALL/pre–B-ALL with t(9;22) samples (n = 42) are red, and CML samples (n = 75) are green.