Caprin 1 overexpression in urothelial carcinomas of bladder B. Akkaya * , Z. Cetin, S. Berker-Karauzum, M. Baykara * Akdeniz University, School of Medicine, Antalya, Turkey Objective: Caprin1 encoded by Cytoplasmic Activation/ Protein-1 gene located in 11p13 chromosome region. It has been reported that Caprin 1 is associated with cell proliferation in various types of cell lineages. Method: We researched whether Caprin 1 might be overexpressed or not in urothelial carcinoma of bladder and its overexpression could be correlated with clinicopathologic parameter (age, sex, invasion). Fifty urothelial carcinoma of bladder (29 infiltrative; 21 non-infiltrative) were stained by immunohistochemically in tissue microarrays. Results: The expression of Caprin 1 was observed in 24infiltrative urotelial carcinoma cases (%82) and 18 non-invasive urothelial carcinoma cases (%85). Age range was 32-85. Eight patients were female, 42patients were male. Conclusion: In the literature Caprin 1 overexpression was reported in different types of tumors including esophageal, stomach, prostate, lung, liver. Caprin 1 overexpression might be correlated with the cellular proliferation potential.