“The pathophysiology underlying the relationship between obesity and cancer is complex and incompletely understood. Until now, it has been unclear if excess fat tissue itself affects cancer progression or if this link is predominantly due to diet and lifestyle of obese individuals. Recent studies show that the state of obesity can accelerate tumor growth irrespective of diet. Based on the apparent link between increased adiposity and several cancers (colorectal, endometrial, breast, and prostate), it has been proposed that adipose tissue has a direct effect on tumors. An emerging body of evidence confirms that this cross talk indeed takes place at several levels.
Adipose tissue is composed of adipocytes, as well as vascular and stromal cells, secreting numerous soluble factors collectively termed adipokines. In addition, infiltration of the immune system cells in obesity leads to increased production of a number of inflammatory cytokines by adipose tissue, thus contributing to the establishment of the metabolic syndrome. Endocrine signaling by adipose tissue-derived molecules has been shown to promote cancer in animal models, matching clinical associations. Recent studies have shown that cells from adipose tissue are capable of trafficking to tumors, thus enabling paracrine action of adipokines from within the tumor microenvironment.”
–Adipose Tissue and Cancer, edited by Michael G. Kolonin (2013)