The effect of obesity on the formation of cancer risk in patients with type 2 diabetes mellitus (literature review)

Abstract

The increased risk of cancer in patients with type 2 diabetes mellitus substantiates the relevance of scientific researches on the mechanisms of association of these diseases. It was found that pathogenetic factors of type 2 diabetes mellitus cause disorders at the level of signaling pathways that control the processes of intracellular metabolism and survival. Obesity significantly increases cancer risk. The procarcinogenic effect of obesity is due to a combination of metabolic and hormonal disorders. The role of hyperinsulinemia, hyperglycemia and cytokine imbalance as factors for dysmetabolic influence has been proved. Hyperinsulinemia causes mitogenic and anti-apoptotic effects. Hyperglycemia due to oxidative stress determines chromosomal aberrations and changes in regulatory gene expression. Proinflammatory cytokines promote the formation of chronic inflammation and microenvironment conducive for the survival of malignant cells. Dysmetabolic changes, in turn, cause hormonal disorders that promote carcinogenesis in hormone-dependent organs. Hyperinsulinemia leads to hyperoestrogenemia, and hyperleptinemia disrupts the synthesis of gonadotropic hormones, contributing to hyperplastic endometrial processes. Excessive concentrations of interleukin-6 and hyperleptinemia stimulate local oestrogen synthesis in adipose tissue of the mammary gland, activating proliferative processes. Hypoadiponectinemia promotes suppression of the immune response and indicates a potentially unfavourable course of cancer di­seases. Understanding the mutually confounding pro-oncogenic effects of metabolic and hormonal disorders in obesity should emphasize the importance of body weight correction in patients with diabetes mellitus, as well as in individuals without carbohydrate metabolism disorders, from the standpoint of preventing not only cardiovascular diseases, but also cancer. The choice of antidiabetic drugs should take into account the need for correction of the body weight of patients, and ineffective conservative treatment of obesity is a pretext for the use of bariatric surgery methods according to medical indications.