This high expression level of both JUNB and CXCR4 was also observed in our previous studies for metastatic breast cancer patients’ CTCs (JUNB: 65% and CXCR4: 90% in patients’ cohort) and for DTCs from the bone marrow of early breast cancer patients (JUNB: 95% and CXCR4: 92% in patients’ cohort) [18,19]. This evidence concerns the gene CXCR4 and breast cancer.