Abstract： @@ Renal cell carcinoma (RCC) is the most common malignant tumour in the adult kidney.Recent studies have shown that inactivation of the tumour suppressor gene VHL located in chromosome 3p25-26 region is responsible for sporadic RCCs.1 According to Kundson's two hit theory,the mechanism of inactivation of a tumour suppressor gene involves mutation,hyper-methylation and loss of heterozygosity (LOH).Mutations and hypermethylation of the VHL gene have been well analysed in RCC,but due to the deficiency of specific gene markers in the VHL region,the exact LOH frequency of the VHL gene in RCC is still unknown.Single nucleotide polymorphisms (SNPs) are regarded as the third generation of human gene markers and are appropriate for LOH analysis.We searched the SNP database in the National Centre for Biotechnology Information,and selected two SNP sites located within the VHL gene region as gene markers.We analysed these two SNP sites in 79 Chinese sporadic RCC patients by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) to detect LOH frequency of the VHL gene and analyse the relationship between VHL LOH and the pathological parameters of RCC.