IL6 and obesity due to melanocortin 4 receptor deficiency: For example, in the PC-3 M-Luc-C6 prostate cancer mouse model, high-fat diet-induced obesity activated the macrophage inhibitory cytokine-1 signaling pathway by metabolically increasing adipose lipolysis and free fatty acid release, which further elevated the expression of IL-8 and IL-6 and subsequently advanced prostate cancer progression [5].