High Expression of a CD38-Like Molecule in Normal Prostatic Epithelium and its Differential Loss in Benign and Malignant Disease

PURPOSE: We characterize an undescribed antigen on prostatic epithelial cells, which is recognized by anti-CD38. MATERIALS AND METHODS: Normal (3 cases), benign hyperplastic (10) and carcinomatous (10) prostatic tissues were analyzed using immunohistochemistry, immuno-electron microscopy and the Western blot test. RESULTS: Comparison of prostatic and lymphatic CD38 antigen revealed identical bands at 45 kD. Electron microscopy demonstrated anti-CD38 reactivity on the cytoplasmic membrane and within the secretory vacuoles. Double labeling with anti-cytokeratin types 5/15 and 8/18 confirmed that basal and secretory normal prostatic epithelial cells express CD38. By contrast, a complete loss was found in malignant (52.8%), tumor-surrounding nonmalignant (16.3%) and benign prostatic hyperplasia derived glands (3.7%). CONCLUSIONS: CD38 is a novel prostatic antigen. Its role in intracellular calcium mobilization may contribute to smooth muscle cell contraction and/or sperm motility.