Patients with a history of previous prostate surgery, indwelling catheter or intermittent catheterization, presence of bladder stones, detrusor acontractility or hypocontractility, urethral strictures, neurogenic bladder dysfunctions, previous diagnosis of bladder cancer or prostate cancer, PSA ≥ 4 ng/mL, or clinical or imaging findings suspicious for malignancy confirmed by biopsy were excluded from all the studies. The gene discussed is KLK3; the disease is Urethral stricture.