| Epithetic ovarian cancer is the first most frequent ovarian cancer. Although the exact mechanism for the development of epithetic ovarian cancer is still unknown, it is well known that environmental factors are the major reasons. Several studies have described that oxidative DNA damage can induce cancer. 8 - hydroxy -2'- deoxyguanosine (8 -OHdG ) is a major form of oxidative DNA damage products and can in-vestigate the role of oxidative DNA damage in the mechanism for the development of cancer as a biomarker.In this study, urinary 8 - OHdG levels from patients with epithet-ic ovarian neoplasm were determined to investigate the role of oxida-tive DNA damage in the mechanism for the development of epithetic o-varian cancer.MATERIALS AND METHODS1. PatientsA total of 38 patients with epithetic ovarian neoplasm admitted tothe Gynecology Department of the First and the Second Affiliated Clin-ical Hospital of China Medical University were included in this study (Mar. 2002 -Oct. 2002). 21 with epithetic ovarian cancer. All epi-thetic ovarian cancer patients were diagnosed according to the criteria of the FIGO,six patients were in Clinical stage ( CS) : I / II , and fif-teen were in CS: IH/IV ; six patients were in mucinous cystadenocarei-noma, and fifteen patients were in serous cystadenocarcinoma,; nine patients were in pathological grade (PG) : G1/G2, and twelve patients were in PG; G3. At same time 17 with epithetic ovarian benign neo-plasm were included. 31 healthy volunteers were used as controls.2. Urine samplesIn order to obtain the precise results, we collected urine samples from all the patients on admission before chemotherapy. 2 ml of urine for each case was collected and stored at -20?C in eppendorf tubes without any additives for the analysis.3. Determination of urinary 8 - OHdG by ELISAEach urine sample was examined for its concentration of 8 -OHdG using a competitive ELISA kit ( 8 - OHdG check, Japan Insti-tute for the Control of Aging, Fukuroi, Shizuoka, Japan) . The speci-ficity of the assay has been established and the determination range was from 0. 5 -200ng/ml, Date were corrected by urinary creatinine and urinary 8 -OHdG (ng/ml)/ creatinine (mg/ml) ratio'is abbre-viated to urinary 8 - OHdG (ng/mg)RESULTS1. The urinary 8 - OHdG levelsThe urinary 8 - OHdG level in epithetic ovarian cancer group wassignificantly higher than the benign neoplasm group (P <0.05) , and was significantly higher than the normal subject group ( P < 0. 05 ). (Tab. 1).2. The comparison of urinary 8 - OHdG levels of different patho-logical classification clinical stages and pathological grades in epithet-ic ovarian cancerUrinary 8 - OHdG levels did not differ among different pathologi-cal classification clinical stages and pathological grades in epithetic o-. varian cancer(P >0.05 ) . ( Tab. 2).DISCUSSIONThe reactive oxygen species ( ROS) formed during exposure to environmental oxidants and during endogenous metabolic processes, play an important role in the pathogenesis of cancer and other degener-ative diseases0 The ROS, such as superoxide anion radicals ( 02 ) , hydrogen peroxide ( H202) , hydroxyl radicals ( OH ?) and singlet oxygen ( 02) , can induce genotoxic damage, including single - and double - strand breaks, DNA - protein cross links. The formation of 8 -hydroxy -2'- deoxyguanosine(8 -OHdG) in vitro by oxygen radi-cals was first reported in 1984 by Kasai and Nishimura, which is hy-droxylation of the C -8 position of 2'- deoxyguanosine as a major form of oxidative DNA damage product. Recently, its levels in the DNAs of animal and human organs as well as in human leukocyte DNA, have been measured as a sensitive biomarker of oxidative DNA damage.During the normal metabolic process, ROS formed by human body can attack DNAs and produce 8 - OHdG, which can be repaired by body repair system, then cut out from DNA strands into blood sys-tern, and lastly excreted into urine without further being metabolized. So 8 - OHdG levels exist in normal...
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