CXCL8 and cancer: One of the established characteristics of ferrocifenes (well-known conjugated ferrocene derivatives, active against breast cancer [27]) is that at concentrations close to IC50, they inhibit cell growth by ageing rather than cell death by apoptosis due to stimulating the secretion of IL-8 and TNF-α in cancer cell models characterised by different sensitivity to pro-apoptotic stimuli (MDA-MB-231, MCF-7, U373, Hs683, and B16F10) [28,29].