Immunohistochemical markers for metastasis in clear cell renal cell carcinoma

Background: Renal cell carcinoma (RCC) is notorious for its high metastatic potential, and 30% of RCC patients present with metastatic disease at the initial presentation and 50% of them will develop metastasis or recurrence after radical surgery. Methods: In an attempt to identify the best predictive marker(s) for metastasis in patients with clear cell RCCs (CRCCs), we examined the expression patterns of 7 metastasis/prognosis-related markers by constructing a tissue microarray including primary CRCC specimens from 30 metastatic and 60 non-metastatic CRCCs. The markers we studied were Ki-67, MUC1, CD44s, PTEN, gelsolin, CA9 and p53. Results: The expressions of Ki-67, PTEN, CD44s, gelsolin and p53 were increased, whereas those of MUC1 and CA9 were decreased in the metastatic CRCCs compared with the non-metastatic CRCCs. The receiver operating characteristic curve-area under the curve (AUC) value of Ki-67 was 0.671, which was the highest among the 7 markers. The optimal cut-off value, sensitivity and specificity of the Ki-67 expression were 1.67%, 86.7% and 41.7%, respectively. Conclusions: These results demonstrate that the Ki-67 expression was increased in metastatic CRCCs, and it had the highest predictive value among the 7 markers. This suggests that Ki-67 could be an excellent predictive marker for metastasis in CRCC patients.