Tumor-associated leukocytes isolated from lymph node+ BC patients secreted 2- to 5-fold more cytokines than lymph node- patients, with the most increased cytokines being thymus and activation-regulated chemokine (TARC/CCL17), IGF-1, IL-3, TNF-β, IL-5, G-CSF, IL-4, and IL-1α. This evidence concerns the gene CCL17 and breast cancer.