Adipose tissue macrophages: the inflammatory link between obesity and cancer?

Abstract

Introduction: Obesity has increased dramatically over the last three decades. Thus, epidemiological evidence linking obesity and cancer has ignited our interest in the relationship between adipose tissue mass and cancer development. Obesity is defined as an excess of adipose tissue that is typified by a chronic, low-grade inflammatory response instigated by macrophage infiltration. Therefore, in this review, we will discuss the putative causal relationship between obesity-induced chronic inflammation and cancer with particular focus on adipose tissue macrophages.

Areas covered: Chronic, low-grade inflammation has long been associated with cancer initiation, promotion and progression. Therefore, signals derived from adipose tissue macrophages may play a significant role in carcinogenesis. In this review we will discuss the molecular mechanisms of cancer development in obesity and highlight possible therapeutic strategies aiming at adipose tissue macrophages.

Expert opinion: The strong correlation between tumor-associated macrophage infiltration and tumor growth and progression emphasizes the value of macrophages as an effective therapeutic target. It remains to be deciphered to what extent adipose tissue macrophages contribute to these processes, especially in tumors growing within or adjacent to adipose tissue. More effort should also be placed on elucidating macrophage differences between humans and mice that may lead to the development of more effective diagnostic and therapeutic strategies.

Keywords:

• adipose tissue
• cancer
• inflammation
• macrophage
• obesity

Declaration of interest

Financial support from The Western Norway Regional Health Authority to M Wagner and H Wiig is gratefully acknowledged. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Notes

This box summarizes key points contained in the article.