CXCR4 and metastatic malignant neoplasm in the lymph nodes: In the present study, we demonstrated that the co-expression of CXCR4 and CXCL12 was correlated with lymph node metastasis and TNM stage of breast cancer, CXCR4 expression was significantly associated with lymph node metastasis and TNM stage, and CXCL12 expression was found to be correlated with TNM stage.