Serum CCL5 levels in BCa patients correlated with lymph node metastasis [84] and analysis of Tregs, which promote tumor metastasis, showed CCR5+/CD4+ and Treg/CCR5+ cell ratios were significantly increased in the lymph nodes of the breast cancer metastasis group [78]. This evidence concerns the gene CCR5 and metastatic malignant neoplasm in the lymph nodes.