Expression of CD133 and CD24 and their different phenotypes in urinary bladder carcinoma

Introduction: Several lines of evidence suggest the contribution of cancer stem cells (CSCs) to the tumorigenicity of bladder cancer. Although CD133 and CD24 CSC biomarkers are associated with survival disadvantages in some cancers, the biological attributes of a specific tumor alters the expression of these markers and any associated phenotypic characteristics. Aim: To analyze CD133 and CD24 expression and their different phenotypes in urinary bladder carcinoma. Material and methods: Expression of CD133 and CD24 and their divergent phenotypes were analyzed in patients with urinary bladder carcinoma (n=60) and correlated with clinicopathological parameters. Results: CD133⁺ and CD24⁺ tumor cells were more frequent in high grade, less differentiated carcinomas (18/22, and 15/17, p=0.022 and 0.01, respectively), muscle invasive tumors (20/22, p=0.017 and 17/17, p=0.001, respectively), and tumors with advanced stage (p=0.001 and 0.007, respectively). The expression of CD24 slightly correlated with lymphovascular invasion (p=0.04), whereas CD133 was associated with distant metastasis. The CD133⁺ CD24⁺ phenotype exhibited more aggressive tumorigenic behavior than other phenotypes. Conclusion: CD133⁺ and CD24⁺ cells correlated with determinants of aggressive behavior and may be involved in tumor progression and distant metastasis. The CD133⁺ subpopulation is likely to have a more potent tumorigenic capacity. Although divergent, the strong correlation between the two populations may support phenotypic plasticity among them. Compared to the CD133⁺ CD24^- and CD133^- CD24⁺ phenotypes, the CD133⁺ CD24⁺ phenotype is the most aggressive. These putative biomarkers can potentially aid in the selection of high-risk patients for more aggressive targeted therapy.