The pattern of CD10 expression in selected pathologic entities of the prostate gland

There is increasing evidence that neuropeptides, including bombesin, may influence growth, angiogenesis, invasiveness, and metastasis in prostate cancer. One of the molecules tightly involved in the regulation of neuropeptide activity is the integral membrane glycoprotein CD10, or neutral endopeptidase 24.11. The pattern of CD10 expression in hyperplastic and neoplastic conditions of the prostate gland has not been previously described. Immunohistochemical staining for CD10 and high-molecular-weight cytokeratin was performed on 92 cases of paraffin-embedded tissue from needle-core biopsy specimens and prostatectomy specimens. Normal and hyperplastic acini showed strong and distinct membrane (apical and intercellular) and cytoplasmic CD10 expression in basal and secretory cells. In contrast, no intercellular membrane or cytoplasmic staining of secretory cells was seen in any cases of adenocarcinoma with Gleason patterns 2 or 3. A subset of high-Gleason grade adenocarcinoma (patterns 4 and 5) displayed CD10 expression in the secretory cells; those cases shared a distinct morphological pattern. Prostatic intraepithelial neoplasia (PIN) showed consistent absence of intercellular membrane and cytoplasmic CD10 expression in the secretory cells, with preserved expression in basal cells. Interestingly, the basal cells in basal cell hyperplasia lacked CD10 expression, and no expression was noted in the secretory cells in all cases examined. Atrophic acini and those associated with acute and chronic inflammation retained CD10 expression. In conclusion, a consistent differential pattern of CD10 expression was seen in basal cell hyperplasia, PIN, and adenocarcinoma, suggesting a role for CD10 in the pathobiology of the prostate gland.