Adiponectin: a link between obesity and cancer.

Adiponectin, an insulin-sensitising hormone produced by adipocytes, has direct antidiabetic, antiatherogenic, anti-inflammatory and antiangiogenic properties. Circulating adiponectin levels are lower in obesity, a disease state that is associated with certain malignancies. Recently, accumulating evidence suggests that adiponectin may have an important protective role in carcinogenesis. There is also evidence that at least some, if not most, cancer cell types express adiponectin receptors; thus adiponectin may act on tumour cells directly by binding and activating adiponectin receptors and downstream signalling pathways. Through its antiangiogenic properties, and also possibly through other mechanisms regulating cell proliferation discussed in this review, adiponectin may prove to be an effective novel anticancer agent. Large association and prospective studies to assess adiponectin levels in relation to risk from cancer, as well as mechanistic studies to prove adiponectin's role in the development of malignancies, and interventional trials to address potential roles of adiponectin in cancer pathogenesis and therapeutics are needed.