FOLH1 and prostate carcinoma: PSMA is a type II transmembrane glycoprotein (also named glutamate carboxypeptidase II or folate hydrolase I) which mainly shows expression on both benign prostate epithelium and prostate cancer (PCa) cells, but expression is also observed in healthy tissues such as the kidneys, small intestine and the salivary glands [2–7].