Lung cancer increases H(2)O(2) concentration in the exhaled breath condensate, extent of mtDNA damage, and mtDNA copy number in buccal mucosa

We have shown that the H(2)O(2) concentration in exhaled breath condensate (EBC) in lung cancer patients increases significantly compared to the EBC of healthy people and revealed the correlation between the H(2)O(2) level in the EBC and amount of mtDNA damage in buccal mucosa cells. The H(2)O(2) hyper-production may trigger mitochondrial biogenesis, thereby resulting in an increase in mtDNA copy number. However, we did not observe a significant difference in the studied parameters between smokers and non-smokers. Overall, our data suggest that H(2)O(2) concentration in the EBC, the extent of mtDNA damage, and mtDNA copy number in buccal mucosa could be potential as an early diagnostic marker of lung cancer.