A CD-38-Like Molecule - A Novel Prostatic Antigen and its Differential Expression in Normal Prostatic Epithelium and Prostatic Disease

Summary:

This study describes for the first time that all normal prostatic epithelial cells (PEC) intensely react with two monoclonal antibodies directed against distinct epitopes of CD38. Direct comparison of prostatic and lymphatic CD38 using Western blotting revealed identical bands at approximately 45 kD, indicating that the molecules recognized were identical. Immunogold electron microscopy demonstrated anti-CD38 reactivity on the cystoplasmic membrane and within the secretory vacuoles. Double labeling with anti-cytokeratin antibodies confirmed that basal and secretory normal PEC intensely react with anti-CD38. By contrast, only 47.2 % of malignant glands were uniformly CD38 positive and, moreover, 5/10 tumor patients exhibited a complete loss of anti-CD38 reactivity by malignant PEC. Interestingly, 16.3 % of the surrounding non-malignant glands were also completely CD38 negative and only 61.6 % uniformly CD38 positive. A similar functional alteration was found in 8/10 BPH patients, with CD38 negative PEC in 81.4 % of analyzed glands and completely CD38 negative glands in 5/10 patients. Since it has been demonstrated that CD38 is a multifunctional protein involved in cell activation, adhesion to endothelium and intracellular calcium mobilization, massive CD38 expression in human prostate may contribute to an understanding of the physiological role of PEC.

Key words:

Benign prostatic hyperplasia - Prostate cancer - CD38 - Prostatic antigen