As other groups have described [33, 34], the growth of E0771 tumors is enhanced in obese mice compared to lean mice, and we have separately shown that plasma or adipocyte derived exosomes that reflect diabetic or insulin resistant features of obesity strongly promote tumor aggressiveness in multiple cancer types [14–16] which led us to hypothesize that exosomes either present in plasma or derived from adipocyte exosomes promote tumor growth and aggressiveness. This evidence concerns the gene INS and obesity due to melanocortin 4 receptor deficiency.