The present study indicates that patients responded to treatment of advanced breast cancer with single-agent paclitaxel or docetaxel leads to an increase in serum IFN-γ, IL-2, IL-6, GM-CSF cytokine levels and enhancement of PBMC NK and LAK cell activity, while they both lead to a decrease of acute phase serum cytokine levels of IL-1 and TNF-α. This evidence concerns the gene CSF2 and breast cancer.