Diabetes and cancer: two diseases with obesity as a common risk factor

Abstract

There is a growing body of evidence to support a connection between diabetes (predominantly type 2), obesity and cancer. Multiple meta-analyses of epidemiological data show that people with diabetes are at increased risk of developing many different types of cancers, along with an increased risk of cancer mortality. Several pathophysiological mechanisms for this relationship have been postulated, including insulin resistance and hyperinsulinaemia, enhanced inflammatory processes, dysregulation of sex hormone production and hyperglycaemia. In addition to these potential mechanisms, a number of common risk factors, including obesity, may be behind the association between diabetes and cancer. Indeed, obesity is associated with an increased risk of cancer and diabetes. Abdominal adiposity has been shown to play a role in creating a systemic pro-inflammatory environment, which could result in the development of both diabetes and cancer. Here, we examine the relationship between diabetes, obesity and cancer, and investigate the potential underlying causes of increased cancer risk in individuals with diabetes. Current treatment recommendations for reducing the overall disease burden are also explored and possible areas for future research are considered.

Keywords: antidiabetic drug; diabetes complications; diabetes mellitus; type 2 diabetes.

Figure 1

Interrelationship between pathological mechanisms and modifiable and non-modifiable risk factors involved in diabetes, obesity and cancer. IGF, insulin-like growth factor.

Figure 2

Possible mechanism by which metformin may be able to inhibit cancer cell growth. AMPK, adenosine monophosphate-activated protein kinase; ER, endoplasmic reticulum; IGF, insulin-like growth factor; LKB1, liver kinase B1; mTOR, mammalian target of rapamycin; TSP, thrombospondin; UPR, unfolded protein response. Adapted with permission from Ref. .