Mutations in the von Hippel-Lindau (VHL) gene refine differential diagnostic criteria in renal cell carcinoma.

BACKGROUND AND OBJECTIVES

Renal cell carcinomas (RCC) with abundant granular cytoplasm include oncocytomas, eosinophilic variants of chromophobe RCC, papillary RCC, collecting duct carcinoma, and some conventional (clear cell) RCC. Tumors with predominantly clear cell cytoplasm include typical chromophobe RCC and conventional (clear cell) RCC. The objective of this study was to determine if mutations in the VHL gene can serve as auxiliary diagnostic criteria in refining histology based subtyping of renal epithelial neoplasia.

METHODS

The study cohort of 67 cases included 24 conventional RCC, 14 chromophobe RCC, 14 papillary RCC, and 15 oncocytomas. Single strand conformational polymorphism (SSCP) was used as a screening procedure for mutations followed by automated sequencing to identify mutations.

RESULTS

Thirteen of the 14 mutations identified were novel, seven of which were in the coding region. In chromophobe RCC, mutations clustered in the 5'UTR/promoter region and have not been previously reported. Exon 3 appeared to favor conventional (clear cell) RCC and correlated with a more aggressive phenotype. Mutations were absent in the papillary and oncocytoma RCC subtypes.

CONCLUSIONS

Exon 3 mutations permitted a morphological distinction between conventional (clear cell) RCC and chromophobe RCC with clear cells. Mutations in the VHL gene refine histologic diagnostic criteria in RCC serving as adjuncts to the present morphology based diagnosis of RCC.