Expression of CD105 cancer stem cell marker in three subtypes of renal cell carcinoma.

Background: CD105 is recently described as a cancer stem cell (CSC) marker.
Objective: The present study was aimed to investigate the expression and prognostic significance of the CSC marker CD105 in different histological subtypes of renal cell carcinoma (RCC).
Methods: Expression of CD105 was evaluated using immunohistochemistry in RCC samples on tissue microarrays including clear cell RCCs (ccRCCs), papillary, and chromophobe RCCs. The association between CD105 expression and clinicopathological features as well as survival outcomes was determined.
Results: In ccRCC, increased tumoral cytoplasmic and endothelial expression of CD105 were significantly associated with advanced stage, renal vein invasion, and microvascular invasion (MVI). In addition, MVI was associated with a worse overall survival (OS). Moreover, in multivariate analysis tumor stage and nuclear grade were independent prognostic factors for OS both in case of tumoral cytoplasmic and endothelial CD105 expression. Additionally, CD105 expression was found to be a predictor of worse OS in univariate analysis. However, in papillary and chromophobe RCC, no significant association was found between CD105 expression and clinicopathological parameters or prognosis.
Conclusions: We showed that CD105 expression was associated with more aggressive tumor behavior, more advanced disease, and worse prognosis in ccRCC but not in the other RCC subtypes.