IGF1 and obesity due to melanocortin 4 receptor deficiency: Although the specific mechanism through which obesity raises the risk of kidney cancer is yet to be determined, the altered circulating levels of adipokines (30), the chronic inflammatory status (31), and modulation of host immunosurveillance (30), and insulin resistance leading to increased insulin and insulin-like growth factor (IGF)-1 levels, which are involved in carcinogenesis may play a significant role (6, 32, 33).