Although CXCL13 overexpression in BC tissues and increased serum level of this chemokine in patients with metastatic disease suggested a role for CXCL13 in the BC progression [138], the activation of this axis was negatively associated with determinants of a poor prognosis, including axillary node involvement and high histological grade and improved outcome in HER2 overexpressing BC [137]. This evidence concerns the gene ERBB2 and breast cancer.