The Expression Pattern of Annexin A1 in Urinary Bladder Urothelial Carcinoma and Its Clinicopathologic Significance

ABSTRACT

BACKGROUND: Annexin A1 (ANXA1) is known to be involved in the progression and differentiation of various tumors. However, its significance and role in bladder carcinogenesis has not been fully elucidated. To determine the role ANXA1 plays in urothelial carcinoma (UC), we investigated the expression of ANXA1 protein in normal urothelial tissue, carcinoma in situ (CIS), and UC of the urinary bladder. METHODS: Protein expression level of ANXA1 and its subcellular localization were analyzed in 88 cases of UCs and corresponding 24 normal tissues and 24 CISs by immunohistochemistry. RESULTS: ANXA1 was significantly down-regulated at all subcellular localization in CIS and in the cytoplasm and membrane of cells of UC, compared to normal tissues. No significant correlation between ANXA1 expression level and tumor depth (pT), growth pattern, and recurrence was found. However, cytoplasmic and membranous ANXA1 were significantly up-regulated in high grade than in low grade UC (p=0.02 in cytoplasm and p=0.03 in membrane). CONCLUSIONS: These results suggest that ANXA1 dysregulation is involved in urothelial carcinogenesis and ANXA1 is potentially a marker for the pathologic differentiation of UC.