The simultaneous over-expression of both the chemokine CCL5 (previously found to be highly expressed by breast cancer cells [64]) and one of its receptors - CCR5 (expressed among others by CD8+ cytotoxic T cells), suggests that tumor cell-derived CCL5 attracts CD8+ cytotoxic T lymphocytes (CTLs) to LumA-R2 tumors. Here, CCR5 is linked to breast cancer.