Immunohistochemical study of carbonic anhydrase IX and claudin-1 in clear cell renal cell carcinoma

Objective Clear cell renal cell carcinoma (CCRCC) is the most common type of renal malignancy. Carbonic anhydrase IX (CAIX) is widely expressed in CCRCC. CAIX may have a role in tumor invasion and metastasis. This function may be related to its association with reduction of cell–cell adhesion. Claudin-1 is a major component of tight junctions of epithelial cells that plays a role in cell adhesion. Claudin-1 downregulation plays a crucial role in epithelial–mesenchymal transition and cancer invasion and metastasis. We aimed to study the expression of CAIX and claudin-1 in CCRCC and their relation to some prognostic parameters such as nuclear grade and T stage. We also studied the relation between both markers in these tumors. Materials and methods The study included 60 nephrectomy specimens of patients with CCRCC. Tumor paraffin sections were stained immunohistochemically for CAIX and claudin-1. Results All studied tumors were CAIX positive, and 53.33% showed high CAIX expression. Low CAIX expression was significantly associated with higher tumor nuclear grade and renal vein invasion but not with tumor stage or capsular infiltration. Regarding claudin-1, 53.3% of tumors were positive. Male patients showed significantly lowered claudin-1 expression. There was significant decreased claudin-1 expression with increasing stage, venous invasion, and capsular infiltration but not with nuclear grade. There was no relation between CAIX and claudin-1. Conclusion Both CAIX and claudin-1 are associated with some indicators of bad prognosis in CCRCC. They could be used as prognostic markers. Claudin-1 may be a factor of invasiveness in CCRCC. There was no relation between CAIX and claudin-1in CCRCC.