20-gene signature can identify patient tumor samples with poor outcome from different human cancer types. Three human cancer types were analyzed: breast cancer [31, 32] (a and b), astrocytoma  (c) and multiple myeloma  (d). The probeset with maximal values was selected for those genes with multiple probesets. Expression values for each gene were mean centered (mean = 0, stdv = 1), and the sum of the expresion values of the 20 genes for each patient sample was computed (20-gene score, see Materials and Methods). Each dataset was divided in three groups of patients depending on the 20-gene score, and the survival of each group was represented in Kaplan-Meier curves. Note that the patients with lower scores (green color) display better survival than those with intermediate or higher scores (blue and red colors, respectively). Survival curves for good prognosis (orange line) and poor prognosis (grey line) breast cancer patients according to 70-gene and 76-gene prognosis profiles are showed (a and b, respectively). Significance of the survival differences is shown (p-val, Wilcoxon signed-rank test). On the right of each survival plot, there are heat maps of the corresponding datasets, and the numbers represent the number of patients in each 20-gene score group. From top to botton, the samples are ranked from lowest to highest 20-gene scores. From left to right, expression values of AURKA, BIRC5, BUB1, CCNA2, CDC2, CDC20, CDKN3, CENPA, CHEK1, CKS2, HMMR, KIF2C, KPNA2, MAD2L1, MCM4, NCAPH, PLK1, TOP2A, TPX2, and UBE2C.