Integration of diverse gene expression signatures for risk prediction. (A) Compendium of gene expression signatures in 295 breast tumors. Shown are correlation values to canonical centroids of classes defined by intrinsic genes (basal, luminal A, luminal B, ErbB2, vs. normal-like), by the 70 genes (poor prognosis vs. good), and by the wound signature (activated vs. quiescent). Orange indicates positive correlation; blue indicates anticorrelation. Each row is a class; each column is a sample. (Lower) Corresponding clinical outcomes; black vertical bar indicated death or metastasis as the first recurrence event. (B) Summary of decision tree analysis. At each node, the dominant risk factor in multivariate analysis is used to segregate patients, and the process is repeated in each subgroup until patients or risk factors became exhausted. We found that the 70-gene signature was able to identify a group of patients with very good prognosis (group 0), and then the wound signature could divide the patients called “poor” by the 70-gene signature into those with moderate and significantly worse outcomes (groups 1 and 2). (C) Distribution of 144 lymph node-positive patients among the three groups defined in B. Because the 70-gene signature was identified by using a select subset of 60 patients with lymph node-negative disease, the decision tree incorporating the 70-gene signature was performed on the independent lymph node-positive subset to have an unbiased evaluation of risk prediction. Hazard ratios of metastasis risk after adjusting for all other factors listed in Table 1 are shown for the three subgroups stratified by the decision tree. (D) Distant metastasis free probabilities of patients stratified by the decision tree analysis. A total of 55, 32, and 57 patients are in group 0, 1, and 2, respectively, and 10 years DMFP for the three groups were 89%, 78%, and 47%, respectively (P = 6.94 × 10-6).