INS and cancer: Reduction of SHBG has been observed in normal BMI postmenopausal women with excess body fat,5 and leads to elevated levels of free circulating hormones, including oestrogens and testosterone, which have been linked to tumour cell proliferation and other carcinogenic processes.4 Further, insulin can activate the Ras/Raf/MAPK and PI3K/Akt/mTOR pathways that may increase cell proliferation and increase the risk of tumour formation.4 Relatively high levels of body fat, particularly in the central region, can also induce inflammatory responses, which can promote cancer development.29