The TP-induced increases in epithelial thickness in the prostate, proliferating cell nuclear antigen (PCNA) expression, and cyclin D1 expression were remarkably reduced, whereas terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL)-positive cells and cleaved caspase-3 levels were increased, in PV-treated rats compared to BPH rats. This evidence concerns the gene CCND1 and benign prostatic hyperplasia.