Analysis of the relationships between the different breast cancer subtypes and disease-free survival showed a higher incidence of HER-2-positive tumors and HR-negative plus HER-2-negative tumors in patients who relapsed or died due to the disease (p < 0.01); whereas no relationship was found between these subtypes and the presence of DTC in bone marrow (Table 5). This evidence concerns the gene ERBB2 and breast cancer.