Detection of damage to the mitochondrial genome in the oncocytic cells of Warthin's tumour

Warthin's tumour of the salivary glands is composed of oncocytic cells cont aining excessive numbers of mitochondria which show frequent structural abn ormalities and reduced metabolic function. Recent evidence of a strong asso ciation between cigarette smoking and the occurrence of Warthin's tumour pr ompted this study, to look for evidence of damage to mitochondrial DNA (mtD NA) that could be the result of an increase in oxidative stress; two-colour fluorescence in situ hybridization (FISH) was developed to show the distri bution of mitochondria with deleted mtDNA in paraffin wax-embedded material . Approximately 10% of mtDNA bears the 'common' 4977 bp deletion. Using the polymerase chain reaction (PCR), the 4977 bp deletion was further quantifi ed, in Warthin's tumour and age-matched normal parotid control tissue. Whil st the deletion was present in all parotid tissue, its presence was signifi cantly higher in oncocytic tumour cells. In a small number of controls, the re was a trend towards higher concentrations of the deletion in smokers. Co pyright (C) 2000 John Wiley & Sons, Ltd.