The survival predictors identified in this study are widely acknowledged prognostic factors both specifically for breast cancer patients (such as HER2 status [11,15,17,25], and time interval between breast cancer and brain metastases [58,59,60]), and for brain metastases patients regardless the cancer type: patients’ age [26,27,36,38], number of brain metastases [37,41,58,61,62], and preoperative KPS [26,38,47]. Here, ERBB2 is linked to breast cancer.