Fibbi et al. reported PDE5 immunolocalization mainly in the fibromuscular stroma and vascular (endothelial and stem cells) in the rat and human prostate from BPH subjects [45]; by contrast, Ückert et al. immunolocalized PDE5 expression also at glandular and subglandular areas of human prostate cancer patients [46]. This evidence concerns the gene PDE5A and benign prostatic hyperplasia.