Prognostic significance of CD44 molecule in renal cell carcinoma

Aim. To analyze the expression and the prognostic value of CD44s and variant v5 and v6 isoforms in a large series of conventional renal cell carcinomas. Methods. The expression of CD44 isoforms was immunohistochemically evaluated in 173 conventional renal cell carcinomas, and was compared with the usual clinicopathological parameters such as tumor size, histological grade, pathological stage, and Ki-67 proliferative index. The relationship of the CD44 expression to the cancer-specific survival was evaluated by log rank test. Results. While normal renal tissue was negative for CD44s protein, it was upregulated in 70 (40.5%) out of 173 carcinomas, and its expression significantly correlated with histological grade (p < 0.001), pathological stage (p = 0.023), and Ki-67 proliferative index (p < 0.001). Moreover, the expression of CD44s protein was an adverse prognostic parameter in univariate survival analysis for patients with tumors expressing high levels of CD44s protein (p = 0.003). CD44v5 and v6 isoforms were expressed in 11 (6.4%) and 28 (16.2%) tumors, respectively. Their expression was significantly higher in tumors with higher histological grade (p=0.001 and p=0.001, respectively). Also, the expression of v6 isoform was higher in tumors with high proliferation activity (p=0.001). Conclusion. CD44s molecule may play a role in the progression of conventional renal cell carcinoma, and may be used in the evaluation of disease outcome.