In vitro studies using normal prostate epithelial and BPH cell lines have investigated TGF‐β‐induced changes in the expression levels of E‐cadherin and claudin‐1 between cells, as well as the function of the intercellular epithelial barrier, using trans‐epithelial electrical resistance measurement assays or fluorescein isothiocyanate–dextran Transwell permeability assays. This evidence concerns the gene CLDN7 and benign prostatic hyperplasia.