title: Overexpression of CD24: association with invasiveness in urothelial carcinoma of the bladder.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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.
authors.affiliation: Department of Pathology and Urology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yoon-La
authors.initials: YL
authors.lastname: Choi
authors.forename: Seung-Hyun
authors.initials: SH
authors.lastname: Lee
authors.forename: Ghee-Young
authors.initials: GY
authors.lastname: Kwon
authors.forename: Cheol-Keun
authors.initials: CK
authors.lastname: Park
authors.forename: Jae-Joon
authors.initials: JJ
authors.lastname: Han
authors.forename: Jong Sun
authors.initials: JS
authors.lastname: Choi
authors.forename: Han Yong
authors.initials: HY
authors.lastname: Choi
authors.forename: Seok-Hyung
authors.initials: SH
authors.lastname: Kim
authors.forename: Young Kee
authors.initials: YK
authors.lastname: Shin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D051927:CD24 Antigen / Q000378:metabolism*; D002295:Carcinoma, Transitional Cell / Q000378:metabolism / Q000473:pathology*; D003593:Cytoplasm / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D001749:Urinary Bladder Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D051927:CD24 Antigen