Prognostic value of CXCR4 expression in patients with clear cell renal cell carcinoma

Introduction: The expression of CXCR4 is implicated in the metastatic dissemination of different cancers. The information on its prognostic value has been very limited in clear cell renal cell carcinoma (ccRCC). Our objective was to explore the prognostic value of CXCR4 in ccRCC. Materials and methods: 104 patients with a ccRCC were studied. There were 69 men and 35 women with an average age of 64.5 years old (range: 34-86 years). The CXCR4 expression was evaluated by immunohistochemistry. The follow-up varied from 12 to 184 months with a mean of 79.5 months. Kaplan-Meier with a log rank test was performed to compare overall survival and cancerspecific survival after surgery. Univariate and multivariate analyses were performed according to the Cox regression model. Results: CXCR4 expression was found in 68/104 (65.4%) of tumor samples. CXCR4 expression was located in the nucleus in 55/68 (80.8%) cases while cytoplasm or membrane location was found in 13/68 (19.2%) cases. High expression was found in 25/68 (36.8%) cases. During follow-up, 39 patients died, of which 26 died of cancer. Kaplan-Meier analysis revealed that a high expression of CXCR4 was associated with a reduced overall survival (p=0.017) and cancer-specific survival (p=0.022). Univariate analysis indicated that a high expression of CXCR4 was a significant factor for a poorer overall survival (p=0.020) and cancer-specific survival (p=0.027). By multivariate analysis, a high expression of CXCR4 appeared to be an independent factor of overall survival (p=0.024) and cancer-specific survival (p=0.028). Conclusion: This study suggested that a high CXCR4 expression was correlated with a worse outcome for ccRCC patients

Different DNA Loidy Patterns for the Differentiation of Common Subtypes of Renal Tumors

Objectives: The common subtypes of renal tumors are conventional or clear cell carcinoma, papillary carcinoma, chromophobe carcinoma and oncocytoma. Each subtype has its distinct histogenesis and clinical evolution. DNA ploidy is viewed as a marker of gross genomic aberrations. The aim of this study is to evaluate the DNA ploidy in the common subtypes of renal tumors to increase our understanding of renal tumor biology and to broaden clinical application of DNA ploidy. Methods: 38 renal tumor samples (13 clear cell RCCs, 12 papillary RCCs, 7 chromophobe RCCs, and 6 oncocytomas) were studied. Five biopsies of different parts of each fresh tumor were subjected to a flow cytometric analysis of DNA ploidy. Results: All tumors except one papillary RCC generated interpretable DNA histograms. Flow cytometric analysis of oncocytomas showed the diploid pattern (29/30 frequencies) while the chromophobe RCC never showed the diploid pattern (0/55 frequencies) (p < 0.01). 3/7 chromopbobe RCCs possessed the hypodiploid stemline. The hypodiploid stemline appeared neither in conventional RCCs (0/63 frequencies) nor in papillary RCCs (0/50 frequencies). The diploid pattern was dominant in conventional and papillary RCCs. 10/13 (76.9%) of clear cell RCCs and 9/11 (81.8%) of papillary RCCs possessed a homogeneous DNA ploidy pattern while only 1/7 (14.3%) has a homogeneous DNA ploidy pattern. 6/7 chromophobe RCCs had multiple aneuploid stemlines. Conclusions: Flow cytometric analysis reveals that conventional and papillary RCCs are more homogeneous than chromophobe RCC. Each subtype of renal tumors possesses a specific DNA ploidy pattern. The analysis of DNA ploidy is useful for the differentiation of common subtypes of renal tumors in morphologically difficult cases