The inflammatory milieu of tumors affects considerably processes of disease development and progression.Inflammatory chemokines, including CCL2 (MCP-1), CCL5 (RANTES), and CXCL8 (IL-8) are major contributors to breast malignancy, acting at many different levels.While CCL2 and CCL5 mainly shift the balance between leukocyte infiltrates in breast tumors in favor of those that facilitate tumor growth, CXCL8 was identified primarily as an angiogenic factor that supports metastatic processes in this disease.In this study, we have analyzed the regulation of CCL2 and CCL5 expression by inflammatory cytokines in breast tumors.Our analyses indicated that TNFα and IL-1 ? are expressed by the tumor cells in 90% of breast cancer patients, and that both cytokines potently up-regulated the release of CCL2 and CCL5 by breast tumor cells and by normal breast epithelial cells that are as yet non-transformed.Combined with additional findings that provided evidence to interactions between inflammatory cytokines and chemokines in breast cancer, we suggest that TNFα and IL-1β from autocrine sources are important up-regulators of CCL2 and CCL5 release in early and advanced stages of disease, as well as of progression-related processes.