KLK3 and benign prostatic hyperplasia: Benign prostatic hyperplasia (BPH), prostatitis (Nadler et al. 1995), ejaculation (Herschman et al. 1997), or manipulation of the prostate gland (Chybowski et al. 1992; Crawford et al. 1992; Tarhan et al. 2005) may cause elevated levels of serum PSA.