Absence of HinfI Restriction Abnormalities in Renal Oncocytoma Mitochondrial DNA.

Renal oncocytomas are characterized by bland-appearing eosinophilic cells with a profusion of mitochondria. Previous work has suggested that these tumors possess a mutation in the 16.5-kbp circular mitochondrial DNA (mtDNA) manifested by an abnormal restriction fragment pattern after digestion with HinfI (Welter et al, Genes Chromosomes Cancer 1989;1:7-82). To better characterize this mtDNA abnormality in renal oncocytomas, we amplified the entire mitochondrial genome from five paired normal and oncocytoma specimens and subjected the amplified fragments to digestion with the restriction enzyme HinfI. No somatically acquired alterations were detected in the mtDNA from any of the five renal oncocytomas. One specimen displayed a known HinfI polymorphism in the mtDNA from both the normal and oncocytoma tissues. Our data do not support the existence of somatically acquired mitochondrial genome abnormalities in renal oncocytomas.