Univariate analysis confirmed the prognostic value of combined gene expression of CK-19, and/or CD44high/CD24low, and/or ALDH1high/CD24low and/or HER2 in the EpCAM(+) CTC fraction for OS (p = 0.001) together with tumor grade (p = 0.030) and ER (p = 0.004) (Table 2). The gene discussed is ESR1; the disease is neoplasm.