MDM2 and neoplasm: In the METABRIC cohort, multivariate Cox proportional hazards regression adjusted for age at diagnosis, tumor stage, radiotherapy, endocrine therapy, chemotherapy, and surgery indicated that MDM2 amplification was an independently prognostic factor on OS (HR AMP vs no AMP, 1.40, 95% CI, 1.01–1.96, P = 0.045; Fig. 4H and Table S17) and BCSS (HR AMP vs no AMP, 1.72, 95% CI, 1.17–2.53, P = 0.006; Fig. 4F and Table S17).