Islet Inflammation: The Link between Type 2 Diabetes and Pancreatic Cancer

Abstract

The role of islet inflammation in type 2 diabetes (T2DM) and pancreatic ductal adenocarcinoma (PDAC) is complex. About 80% of pancreatic cancer patients have glucose intolerance or T2D. Chronic type 2 diabetes increases risk for pancreatic cancer, but the mechanisms are unknown. In this context two hypotheses exist: (i) pancreatic cancer causes diabetes and (ii) diabetes promotes the development of pancreatic cancer. Pancreatic ductal adenocarcinoma is the most common and deadly form of pancreatic cancer that is associated with diabetes. There are many possibilities by which obesity links to pancreatic cancer. These possibilities include insulin resistance, hyperinsulinemia and inflammation. Adipose tissue deposition near pancreas (peri-pancreatic depot) increase proinflammatory response to a high fat or high calorie containing diet. Inflammatory processes in the islets act as main mediators during the development and progression of pancreatic cancer. Recently, studies have been carried out to investigate the underlying mechanisms that contribute to tumorigenesis induced by inflammation. Tumor-elicited inflammation, secretion of pro-inflammatory cytokines and migration of immune cells play the key roles in initiation, promotion and progression of malignant metastasis in pancreatic cancer. Initiation and progression of islet inflammation in diabetes and pancreatic cancer occurs as a result of various protein–protein interactions and genetic events. The increase in pancreatic cancer cases may be attributed to the obesity endemic and obesity mediated Type 2 diabetes. The existence of link between islet inflammation in chronic diabetes and pancreatic cancer cannot be ignored, although the details about the underlying mechanisms are not clear, and must be studied in detail.