IGF1 and Obesity: In particular, obesity can lead to insulin resistance, where circulating levels of insulin and bioavailable insulin‐like growth factor (IGF) are elevated, leading to stimulation of cell proliferation and downregulation of apoptosis.17 Obese individuals also have abnormal circulating levels of adipokines (e.g., higher levels of leptin and lower levels of adiponectin), proinflammatory cytokines (e.g., tumor necrosis factor‐α and interleukin‐6) and endogenous sex steroids, which are synthesized in peripheral adipose tissue and may contribute to cancer development.17, 18