['Cancer stem cells (CSCs) represent a population with tumour-initiating, self-renewal, and differentiation potential. This study aimed to evaluate the expression patterns and clinical significance of chemokine receptor type 4 (CXCR4) as a novel CSC marker in renal cell carcinoma (RCC).', 'The expression of CXCR4 was examined in 173 well-defined renal tumour tissues, including 106 (61.5\xa0%) clear cell renal cell carcinomas (ccRCCs), 35 (20\xa0%) papillary renal cell carcinomas (pRCCs), and 32 (18.5\xa0%) chromophobe renal cell carcinomas (ChRCCs), by immunohistochemistry on a tissue microarray. The association between expression of this marker and clinicopathologic parameters was then analysed.', 'There was a significant difference in the expression levels of CXCR4 in the ccRCC samples compared to the ChRCC and pRCC samples (P\xa0<\xa00.001). Increased expression of CXCR4 was significantly correlated with higher-grade tumours (P\xa0<\xa00.001) and worse stage (P\xa0=\xa00.001). A significant association was also found between expression of CXCR4 and microvascular invasion (P\xa0=\xa00.018). Among RCC subtypes, comparison of the differences between CXCR4 expression in low- and high-grade tumours demonstrated that pRCC tumours had a significantly higher expression of CXCR4 (P\xa0<\xa00.001) than ccRCC tumours (P\xa0=\xa00.01).'] Is reduced expression of CXCR4 , a novel renal cancer stem cell marker , associated with high-grade renal cell carcinoma?