The receptor CXCR4 and its ligand CXCL12 play crucial roles in breast cancer. Despite the fact that the spontaneous feline mammary carcinoma (FMC) is considered a suitable model for breast cancer studies, the importance of the CXCR4/CXCL12 axis in FMC is completely unknown. | CXCR4 and its ligand CXCL12 display opposite expression profiles in feline mammary metastatic disease with the exception of HER2-overexpressing tumors