CXCR4 and breast carcinoma: In order to provide a deeper insight into the role of the CXCR4/CXCL12 axis in FMC, CXCR4 and CXCL12 expression was analyzed and quantified in PT, RM and DM from female cats with mammary carcinoma and its expression was correlated with blood serum CXCL12 levels and molecular subtypes.