Association of Diabetes Mellitus and Alcohol Abuse with Cancer: Molecular Mechanisms and Clinical Significance

Diabetes mellitus (DM), one of the metabolic diseases which is characterized by sustained hyperglycemia, is a life-threatening disease. The global prevalence of DM is on the rise, mainly in low- and middle-income countries. Diabetes is a major cause of blindness, heart attacks, kidney failure, stroke, and lower limb amputation. Type 2 diabetes mellitus (T2DM) is a form of diabetes that is characterized by high blood sugar and insulin resistance. T2DM can be prevented or delayed by a healthy diet, regular physical activity, maintaining normal body weight, and avoiding alcohol and tobacco use. Ethanol and its metabolites can cause differentiation defects in stem cells and promote inflammatory injury and carcinogenesis in several tissues. Recent studies have suggested that diabetes can be treated, and its consequences can be avoided or delayed with proper management. DM has a greater risk for several cancers, such as breast, colorectal, endometrial, pancreatic, gallbladder, renal, and liver cancer. The incidence of cancer is significantly higher in patients with DM than in those without DM. In addition to DM, alcohol abuse is also a risk factor for many cancers. We present a review of the recent studies investigating the association of both DM and alcohol abuse with cancer incidence.