DKK3 and benign prostatic hyperplasia: We recently demonstrated that in patients with PCa seminal plasma Dkk-3 levels are significantly elevated 2 despite the reduced expression of Dkk-3 in secretory epithelial cells 1,3 indicating that Dkk-3 derived from tumor neovasculature/stroma is able to diffuse through the diseased tissue into the prostatic fluid while in normal/BPH tissue an intact basement membrane prevents leakage from the stroma to the epithelial compartment and vice versa.