Expression of enhancer of zeste homolog 2 correlates with survival outcome in patients with metastatic breast cancer: Exploratory study using primary and paired metastatic lesions

In metastatic breast cancer, the status of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), as well as the Ki-67 index sometimes change between primary and metastatic lesions. However, the change in expression levels of enhancer of zeste homolog 2 (EZH2) between primary and metastatic lesions has not been determined in metastatic breast cancer.