IL6 and breast cancer: Adipose-derived stem cells possess tumour-supporting functions through provision of migratory cells which secrete trophic factors, increasing vascularisation and contributing to survival and proliferation of malignant cells.140 Adipose tissue secretes cytokines known as adipokines, eg, TNF-α, IL-6, IL-8, PAI-1, MCP-1, adiponectin, resistin, leptin, insulin growth factor, and steroid hormones, some of which have been studied in relation to cancer,142 eg, leptin upregulates activity in signalling pathways in breast cancer tumours that play a role in proliferation (Figure 1).13