Figure 3. A CSC-based mitochondrial 4-gene signature predicts distant metastasis and tumor recurrence in ER(+) breast cancer patients. To optimize its predictive value, we constructed a short 4-gene signature, which revealed an increase in prognostic value, related to distant metastasis (HR=1.91; P=2.2e-08). This 4-gene signature was also able to predict tumor recurrence in the same patient population (HR=1.68; P=1.2e-15). See also Supplementary Tables 2 and 3 and 3. Therefore, these CSC-based mitochondrial signatures may provide a new prognostic approach for predicting treatment failure in breast cancer patients. DMFS, distant metastasis free survival; RFS, relapse free survival.