IGF1 and obesity due to melanocortin 4 receptor deficiency: Although the underlying reasons for the association of obesity with bladder cancer risk are not well understood, several explanations have been proposed, including insulin resistance with increased production of insulin-like growth factor 1 and elevated nutrient availability [5], reprogramming of cellular lipid metabolism [6], chronic inflammation associated with obesity, and the role of adipocytes in the tumour microenvironment [7].