Survival prediction analyses of the different Cox models. (A) Models for all patients; (B) Models for ER-positive patients; (C) Model for ER-negative patients; (D) Models for HER2-positive patients. 1) Hazard ratio and p-value of the Cox proportional hazard model (Cox-model), for both the training and testing sets, respectively; 2) Kaplan-Meier survival estimates of relapse-free survival (RFS) among training and testing sets, respectively, according to each model. Patients were stratified into high-risk (red curve) and low-risk (blue curves) groups based on their respective risk score, which was defined as the natural logarithm of the hazard ratio. The chosen cut-off value for stratification into high and low-risk groups was zero. P-values were obtained from the log-rank test. + denotes observations that were censored owing to loss to follow-up or last contact.
Fan et al. BMC Medical Genomics 2011 4:3 doi:10.1186/1755-8794-4-3