Obesity, adipokines, and prostate cancer (review)

Prostate cancer, the third most common cancer in men worldwide, varies substantially according to geographic region and race/ethnicity. Obesity and associated endocrine variation are foremost among the risk factors that may underlie these regional and ethnic differences. The association between obesity and prostate cancer incidence is complex and has yielded inconsistent results. Studies that have linked obesity with prostate cancer mortality, advanced stage disease, and higher grade Gleason score, however, have produced more consistent findings, indicating that obesity may not necessarily increase the risk of prostate cancer, but may promote it once established. Additionally, metabolic syndrome, which includes disturbed glucose metabolism and insulin bioactivity, may also be associated with prostate carcinogenesis. Adipokines, defined as biologically active polypeptides produced by adipose tissue, have been linked with a number of carcinogenic mechanisms, including angiogenesis, cell proliferation, metastasis, and alterations in sex-steroid hormone levels. A number of emerging studies have implicated the role of adipokines in prostate carcinogenesis. This review explores the specific roles of several adipokines as putative mediating factors between obesity and prostate cancer with particular attention to leptin, interleukin-6 (IL-6), heparin-binding epidermal growth factor-like growth factor (HB-EGF), vascular endothelial growth factor (VEGF) and adiponectin.