Comparison of hydrogen peroxide generation and the content of lipid peroxidation products in lung cancer tissue and pulmonary parenchyma

Lipid peroxidation, as a well-known index of reactive oxygen species activi ty, not only in lung biochemistry, is an oxidative process associated with membrane lipid destruction. Also, the oxidative modification of nucleic aci ds by reactive oxygen species is of remarkable biological importance as it may contribute to malignant conversion, but its exact role in lung cancer b iology is still not clear. Our study aimed to investigate the level of lipi d peroxidation es vivo in tumour tissue and lung parenchyma obtained from p atients with lung cancer. Forty-two patients with lung cancer were enrolled into the study. During a surgical resection, tumour tissue and lung parenc hyma were obtained and concentration of lipid peroxidation products, thioba rbituric acid-reactive substances and Schiff bases, and spontaneous generat ion of hydrogen peroxide, were measured. The concentration of thiobarbituri c acid-reactive substances (P < 0.001) in the tumour tissue was higher than that in lung parenchyma. In small cell lung cancer as well as in squamous cell carcinoma patients, a positive correlation between spontaneous generat ion of hydrogen peroxide in tumour tissue and clinical stage (r = 0.43; r = 0.46; respectively) was found. Our results prove enhanced lipid peroxidati on in cancer tissue as compared with matched-lung parenchyma. In small cell lung cancer and squamous cell carcinoma patients, the high level of oxidat ive stress, expressed as a spontaneous generation of hydrogen peroxide in t umour tissue, was associated with clinical progression of tumour's stage.