Gene expression, due to the combination of AR and DHT, increases the expression of prostate-specific antigen (PSA) and growth factors such as epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and insulin-like growth factor-1 (IGF-1), which contribute to the development of BPH. This evidence concerns the gene KLK3 and benign prostatic hyperplasia.