Kind S, Büscheck F, Höflmayer D, et al. - A tissue microarray comprising samples of 17,747 tumors with annotated clinicopathological and molecular data was immunohistochemically investigated for Claudin-1 (a membrane-tight junction protein and important for the sealing of the paracellular cleft in epithelial and endothelial cells) expression in order to assess the possible significance of Claudin-1 expression in prostate cancer. Results recognized a unique role for Claudin-1 in prostate cancer. Moreover, in a fraction of prostate cancers, the protein was overexpressed and raised Claudin-1 expression levels prognosticated a favorable prognosis in ERG-positive cancer.