The upregulation of TGF-β1 (which is produced by prostatic stromal cells) during BPH would facilitate expansion of the stromal compartment, epithelial to mesenchymal transition, down-regulation of claudin-1, and epithelial barrier damage (Schauer and Rowley, 2011; De Nunzio et al., 2016; Wang et al., 2020; Chen et al., 2021). This evidence concerns the gene TGFB1 and benign prostatic hyperplasia.