Overexpression of CD24 - Association with invasiveness in urothelial carcinoma of the bladder

초록

Context.-CD24, originally described as a B-cell marker, has gained considerable attention in tumor research. High rates of CD24 expression have been found in several types of carcinomas that are significantly associated with a more aggressive course of the disease. To our knowledge, the expression of CD24 in urothelial carcinoma (UC) of the bladder has not been previously reported. Objective.-To determine the expression of CD24 in UCs and the association between CD24 levels and tumor grade and stage. Design.-Urothelial carcinomas (48 cystectomy, 87 transurethral biopsy), including 56 pTa, 29 pT1, 19 pT2, and 31 pT3, were analyzed immunohistochemically using an anti-CD24 monoclonal antibody. The intensity of CD24 staining was semiquantitatively scored as high-level or low-level expression. Results.-In normal urothelium, CD24 was localized to the cytoplasm of the luminal cell layer with very low intensity. CD24 expression was upregulated in noninvasive UCs, and a high level of expression was correlated with the tumor grade (P=.003). Invasive UCs demonstrated strong diffuse cytoplasmic overexpression of CD24 and the difference in CD24 expression between invasive and noninvasive UC was statistically significant (P <.001). Conclusions.-CD24 protein is overexpressed in a significant number of bladder UCs. The high level of CD24 expression with loss of apical localization is a marker for stromal invasion and high tumor grade in UC. This study provides the basis for future investigations of CD24 as a potential serum marker or target of antibody-based therapeutics in bladder UC.

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