Immunohistochemical staining in situ confirmed localisation of claudin-4 and PSMA to the membrane of luminal cells of benign epithelial glands and HG-PIN as well as PCa cells (Chang et al, 1999), with increasing expression for claudin-4 from benign, through premaligant to malignant, being most evident in metastatic PCas. The gene discussed is CLDN4; the disease is posterior cortical atrophy.