Y-chromosome loss is frequent in male renal tumors.

BACKGROUND: Loss of the Y-chromosome is a common event in different tumor types but its prevalence and clinical relevance in renal cell tumors is still not understood. METHODS: It was the aim of this study to estimate the frequency and clinical relevance of Y-loss in kidney neoplasms. A cohort of 1,252 male renal tumors was analyzed in a tissue microarray format by fluorescence in-situ hybridization (FISH). RESULTS: Y-loss was found in 47% of tumors. The frequency of this alteration varied markedly between kidney tumor subtypes. Y-loss was most prevalent in papillary renal cell carcinoma (RCC) (77%) followed by chromophobe RCC (60%), oncocytoma (51%), clear cell RCC (39%) and clear cell (tubulo)papillary RCC (19%). Y-loss was linked to higher patient age and smaller tumor size at diagnosis. Mean age (95% CI) was 65 (64-66) years in patients with Y-loss in their tumor compared to 60 (58-61) years in patients without Y-loss (P<0.0001). Significant correlations between Y-loss and tumor phenotype were found only for papillary carcinomas (P=0.002), especially for type 1 (P=0.03). CONCLUSIONS: Y-loss is present in different histologic subtypes of renal neoplasm. The highest frequency is in papillary RCC, where it may represent a potentially relevant prognostic biomarker suggesting favorable disease outcome.

Prevalence and clinical significance of VHL mutations and 3p25 deletions in renal tumor subtypes.

PURPOSE: To evaluate prevalence and clinical impact of VHL mutations and deletions (3p), a cohort of consecutive kidney tumors was analyzed by DNA sequencing and fluorescence in-situ hybridization (FISH). PATIENTS AND METHODS: The study includes 1,805 patients with renal tumors who were surgically treated at the Department of Urology at the University Medical Center Hamburg-Eppendorf between 1994 and 2015. The cohort included 1,176 clear cell, 270 papillary, 101 chromophobe, and 28 clear cell (tubulo) papillary cancers, as well as 149 oncocytomas and 81 less common subtypes. RESULTS: Among 431 successfully analyzed tumors, VHL mutations were found in 59.3% of clear cell, 5.2% of papillary, 3.1% of chromophobe carcinomas and in 7.3% of oncocytomas as well as in the rare kidney tumor types (25%-60%). FISH analysis was successful in 1,403 cases. 3p25 deletion was found in 57.2% of clear cell, 17.6% of papillary, 17.7% of chromophobe carcinomas and in 11.9% of oncocytomas as well as in the rare kidney tumor types (16.7%-50%). No statistically significant associations between VHL mutation/deletion and tumor grade, stage, and clinical outcome was found. Only in the subgroup of papillary cancers, 3p deletion was significantly associated with lymph node and distant metastasis as well as with poor patient outcome (p < 0.05 each). CONCLUSIONS: The presence of a VHL mutation in virtually all renal tumor subtypes suggests that VHL analysis cannot be used to distinguish between renal tumor subtypes. Consequently, anti-VHL treatment strategies should not be limited to patients with clear cell cancer.