*Review* **Obesity, Inflammation, and Prostate Cancer**

### **Kazutoshi Fujita \*, Takuji Hayashi, Makoto Matsushita, Motohide Uemura and Norio Nonomura**

Department of Urology, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan;takujihayashi0929@gmail.com (T.H.); matsushita@uro.med.osaka-u.ac.jp (M.M.); uemura@uro.med.osaka-u.ac.jp (M.U.); nono@uro.med.osaka-u.ac.jp (N.N.) **\*** Correspondence: kazu.fujita2@gmail.com; Tel.: +81-6-6879-3531; Fax: +81-6-6879-3539

Received: 19 January 2019; Accepted: 4 February 2019; Published: 6 February 2019

**Abstract:** The prevalence of obesity is increasing in the world, and obesity-induced disease, insulin-resistance, cardiovascular disease, and malignancies are becoming a problem. Epidemiological studies have shown that obesity is associated with advanced prostate cancer and that obese men with prostate cancer have a poorer prognosis. Obesity induces systemic inflammation via several mechanisms. High-fat diet-induced prostate cancer progresses via adipose-secretory cytokines or chemokines. Inflammatory cells play important roles in tumor progression. A high-fat diet or obesity changes the local profile of immune cells, such as myeloid-derived suppressor cells and macrophages, in prostate cancer. Tumor-associated neutrophils, B cells, and complements may promote prostate cancer in the background of obesity. Interventions to control systemic and/or local inflammation and changes in lifestyle may also be viable therapies for prostate cancer.

**Keywords:** obesity; inflammation; prostate cancer; immune cells; cytokine; high-fat diet
