Adipose tissue:Critical contributor to the development of prostate cancer.

The prostate is surrounded by periprostatic adipose tissue. Although adipose tissue was thought to play limited physiological roles, it has recently been recognized as an active endocrine organ, secreting growth factors and adipokines. Epidemiologically, obesity is associated with prostate cancer progression. A major mechanism to explain the link between obesity and cancer includes the insulin and insulin-like growth factor (IGF)-1 axis, sex steroids, and adipokines. When prostate cancer cells invade periprostatic adipose tissue, adipose tissue contributes to create the tumor microenvironment, mainly via adipokine secretion. Furthermore, direct crosstalk between adipocytes and cancer cells can exist. We showed that fatty acid-binding protein 4 (FABP4) released from adipocytes was taken up into prostate cancer cells and may act as a carrier of an energy source for the invasion. Bone is an adipocyte-rich organ and is the common metastatic site of prostate cancer. In the microenvironment of bone metastases, tumor cells, osteoblasts, osteoclasts, adipocytes, and other stromal cells are interacting with one another and organizing a complex system. Thus, growing evidence implicates adipose tissue as a critical contributor to the development of prostate cancer. A deeper understanding of the mechanisms leads to more effective therapeutic strategies for prostate cancer. J. Med. Invest. 65:9-17, February, 2018.