Absence of HinfI restriction abnormalities in renal oncocytoma mitochondrial DNA

Renal oncocytomas are characterized by bland-appearing eosinophilic cells w ith a profusion of mitochondria. Previous work has suggested that these tum ors possess a mutation in the 16.5-kbp circular mitochondrial DNA (mtDNA) m anifested by an abnormal restriction fragment pattern after digestion with HinfI (Welter et al, Genes Chromosomes Cancer 1989;1:79-82). To better char acterize this mtDNA abnormality in renal oncocytomas, we amplified the enti re mitochondrial genome from five paired normal and oncocytoma specimens an d subjected the amplified fragments to digestion with the restriction enzym e HinfI. No somatically acquired alterations were detected in the mtDNA fro m any of the five renal oncocytomas, One specimen displayed a known HinfI p olymorphism in the mtDNA from both the normal and oncocytoma tissues, Our d ata do not support the existence of somatically acquired mitochondrial geno me abnormalities in renal oncocytomas.