Because MET is required for efficient tumour colonisation [10, 25], our findings provide an explanation as to why EZH2-deficient breast cancer cells display reduced capacity to colonise new organs and form metastasis in mice models and patient-derived xenografts [13–16], as well as to the oncogenic behaviour of EZH2 as a marker of poor prognosis in breast cancer patients (this study and [24, 26, 27]). This evidence concerns the gene EZH2 and breast cancer.