TNF and breast cancer: In parallel, M1 macrophages are generally regarded as anti-tumor cells that constitute a major source for pro-inflammatory cytokines such as tumor necrosis factor α (TNFα) and interleukin-1β (IL-1β) [70,73]; whereas these cytokines can promote anti-tumor activities at certain stages of the malignancy process, they are also often linked to chronic inflammation and to pro-metastatic effects in BC and other malignancies as well [45,74,75,76,77,78,79].