The contribution of each pathway to carcinogenesis in obesity cannot be assessed in this nonmechanistic descriptive study, but the changes induced by surgery in this study seem sufficiently large to suggest that at least some of the molecular pathways are being deactivated, presumably by reducing the adipose tissue mass and other factors such as reduced insulin and insulin receptor signaling. This evidence concerns the gene INSR and obesity due to melanocortin 4 receptor deficiency.