Many in vitro and in vivo studies have indicated that the activation and dysregulation of prostatic immune cells, and the release of several cytokines and growth factors including IL-2, IL-4, IL-6, IL-17, fibroblast growth factor 2 (FGF-2), were both associated with the initiation and progression of BPH [23]. This evidence concerns the gene IL4 and benign prostatic hyperplasia.