α-blockers (AB) plus 5-α reductase inhibitors (5ARI) combination therapy is recommended as a first-line treatment for patients with BPH, with moderate to severe LUTS, at an increased risk of disease progression (i.e., those with higher prostate volume, higher prostate-specific antigen (PSA) concentration, advanced age, higher post-void residual volume, lower peak urinary flow rate (Qmax)) [9, 12, 13] and where long-term treatment (> 12 months) is intended. This evidence concerns the gene KLK3 and benign prostatic hyperplasia.