Oxidative damage DNA: 8-oxoGua and 8-oxodG as molecular markers of cancer

BACKGROUND: The broad spectrum of oxidative damage DNA biomarkers: urinary excretion of 8-oxodG (8-oxo-7,8-dihydro-2′-deoxyguanosine), 8-oxoGua (8-oxo-7,8-dihydroguanine) as well as the level of oxidative damage DNA in leukocytes, was analyzed in cancer patients and healthy subjects. MATERIAL/METHODS: 222 cancer patients and 134 healthy volunteers were included in the analysis, using methodologies which involve HPLC (high-performance liquid chromatography) prepurification followed by gas chromatography with isotope dilution mass spectrometry detection and HPLC/EC. RESULTS: For the whole patient population (n=222) the median values of 8-oxoGua and 8-oxodG in urine samples were 12.44 (interquartile range: 8.14–20.33) [nmol/24 hr] and 6.05 (3.12–15.38) [nmol/24 hr], respectively. The median values of 8-oxoGua and 8-oxodG in urine samples of the control group (n=85) were 7.7 (4.65–10.15) [nmol/24 hr] and 2.2 (1.7–2.8) [nmol/24 hr], respectively. The level of 8-oxodG in DNA isolated from leukocytes of the patient population (n=179) and of the control group (n=134) was 4.93 (3.46–9.27) per 10’6 dG and 4.46 (3.82–5.31) per 10’6 dG, respectively. CONCLUSIONS: The results suggest that oxidative stress in cancer patients, demonstrated by augmented amounts of these modifications in urine, could be typical not only for affected tissue but also for other tissues and even the whole organism. An assay that enables the determination of levels of basic markers of oxidative stress might be applied in clinical practice as an additional, helpful marker to diagnose cancer.