Since breast cancer cells express elevated levels of not only IL-1β but also other pro-inflammatory cytokines, Safina et al. showed, using an in vitro model showed that IL1-β and TNF-α cooperate with TGF-β in the production of MMP-9 by breast cancer cells and TGF-β activated protein kinase 1 (TAK1) is required for this process [30]. Here, TNF is linked to breast cancer.