CD10 immunohistochemical staining in urothelial neoplasms.

CD10, or common acute lymphoblastic leukemia antigen, is a cell surface neutral endopeptidase that inactivates various bioactive peptides. It is expressed by hematopoietic cells and their neoplasms and in a variety of nonhematopoietic tissues and neoplasms. CD10 has been suggested as a useful marker for urothelial carcinoma, but the few studies of CD10 in urothelial tissues have shown varying results; a comparative study of the CD10 immunoprofile in a range of urothelial tumors has not been performed. We report the CD10 immunoprofile of 70 cases representing urothelial lesions as defined by the World Health Organization Classification (2004) of urothelial neoplasia. We demonstrated moderate to strong CD10 immunohistochemical staining in 67% (40/60) of urothelial neoplasms, with a predominantly cytoplasmic staining pattern. We found a statistically significant difference in staining intensity (scale, 0-3) between high-grade neoplasms (mean, 2.5), dysplasia (mean, 1.7), and low-grade lesions (mean, 1.3), with the high-grade group showing a propensity for a more diffuse staining distribution than the low-grade group. Larger studies incorporating molecular genetic techniques should help better define the role of CD10 in urothelial tumorigenesis.