Prognostic significance of tenascin-C expression in clear cell renal cell carcinoma.

Tenascin-C is an extracellular matrix protein that plays an important role in cell proliferation, migration and tumor invasion in various types of cancer. However, few reports exist on tenascin-C expression in renal cell carcinoma (RCC). This study aimed to assess the prognostic significance of tenascin-C in clear cell RCC. Using immunohistochemistry, 137 formalin-fixed, paraffin-embedded tissue sections obtained from patients with clear cell RCC were examined for tenascin-C expression. Tenascin-C expression was observed in 55 (40.1%) of the 137 clear cell RCC sections. Tumor cells displayed membranous and/or cytoplasmic staining for tenascin-C. Tenascin-C expression was more prominent near the pseudocapsule of the tumor and around the tumor vessels. Tenascin-C expression was significantly associated with a higher stage (P=0.0065) and higher nuclear grade (P=0.0001). However, there was no correlation between the tenascin-C expression and venous involvement. The cancer-specific survival rate in patients with a tenascin-C-positive primary tumor was significantly lower than that in those with a tenascin-C-negative primary tumor in univariate analysis (P=0.0017). However, tenascin-C expression did not exhibit a significant value for cancer-related death in the Cox regression analysis. In patients with stage 1-3 disease, the 5-year metastasis-free rate in patients with the tenascin-C-positive primary tumor was significantly lower than that in those with the tenascin-C-negative primary tumor (67.8 vs. 88.5%, respectively; P=0.0038). The Cox regression analysis showed that tenascin-C expression is a significant predictor of metastasis (P=0.0345). The tenascin-C expression was strongly related to the stage, nuclear grade and 5-year metastasis-free rate. Therefore, tenascin-C expression may be a possible marker for the metastatic potential of clear cell RCC.