Expression of Claudin-1 and -7 in Clear Cell Renal Cell Carcinoma and Its Clinical Significance

PURPOSE We investigated the correlations between the expression of claudin-1 and claudin-7 in clear cell renal cell carcinoma (clear cell RCC) and clinical parameters. MATERIALS AND METHODS The subjects of this study were 119 patients with confirmed clear cell RCC between January 2000 and December 2007. Their RCC tissues were immunohistochemically stained for claudin-1 and claudin-7. The correlations between the expression of claudin and parameters such as sex, age, body mass index (BMI), tumor size, TNM stage, Furhman nuclear grade, postoperative distant metastasis, and cancer-specific survival were analyzed. RESULTS Among the total 119 subjects, claudin-1 was expressed in 18 (15.1%) and claudin- 7 in 31 (26.1%). Claudin-1 was expressed in patients who were older (p=0.007), who had a greater tumor size (p=0.001), who had a higher pathologic T stage (p=0.009), who had preoperative distant metastasis (p=0.035), and who had a higher Furhman nuclear grade (p=0.004). Claudin-7 was expressed only in patients who had a higher Furhman nuclear grade (p=0.031). The risk of postoperative distant metastasis was associated with the expression of claudin-1 (p<0.001) but not with the expression of claudin-7 (p=0.668). The expression of claudin-1 and -7 was not associated with cancer-specific survival (p>0.05). CONCLUSIONS In clear cell RCC, claudin-1 was expressed in patients who were older and who had a greater tumor size, who had higher T or M stages, and who had a higher Furhman nuclear grade. The expression of claudin-1 was associated with a higher risk of postoperative distant metastasis.