Clear cell renal cell carcinoma is the most common malignant renal neoplasm (70–80% of renal cancers).  These tumors are associated with a deletion in chromosomes 3p.    The von Hippel-Lindau (VHL) gene lies in the deleted region, and is thought to act as a tumor suppressor gene in both the sporadic and familial forms of this tumor.  In difficult cases to classify histologically, knowledge of genetic abnormalities within the tumor can be important to sub-classifying renal carcinomas.