We addressed the role of the simultaneous expression of IL-6 and RANTES in breast cancer progression using two cell lines belonging to different subtypes of breast cancer, the luminal cell line MCF-7, which has a low metastatic potential and invasive ability, and MDA-MB-231 cells, a basal breast cancer cell line with a high metastatic potential. The gene discussed is CCL5; the disease is breast carcinoma.