**1. Introduction**

Prostate cancer (PCa) is one of the most common hormone-dependent cancers. Androgen-deprived therapy (ADT) has been the standard option for PCa. It is initially effective in most PCa cases; however, PCa becomes refractory for ADT in spite of the castration level of serum testosterone, which is called "castration-resistant prostate cancer" (CRPC). There have been multiple studies on the efficacy of various agents that include androgen-receptor (AR) targeted agents and anticancer drugs.

Many studies have demonstrated the aberrant activation of fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling in several cancers, including head and neck, lung, breast, endometrial, bladder, and prostate cancer [1,2]. Herein, we review the FGF family's involvement in the development and progression of prostate cancer. We mainly discuss the representative molecules in each subfamily: FGF9 as classic FGFs, FGF19 as endocrine FGFs, and FGFR2IIIb.
