Reactive oxygen species are engaged in the process of carcinogenesis. It was found that oxidative stress level is significantly elevated in children with neoplasms. Moreover, their antioxidant barrier is deficient and does not control free radical reactions. Protein carbonyl groups are a well known marker of oxidative stress in organism. Glutathione peroxidase (GPx) and superoxide dismuthase (SOD) are the most important components of enzymatic antioxidant barrier in humans. THE AIM of the study was to analyze the protein carbonyl groups' content in plasma and evaluation of erythrocyte GPx and SOD activity in children who have completed the oncological treatment.
Patients: 60 children, aged from 6 to 16 years, who have completed the treatment at least a year before they were examined together with a group of 61 healthy children of 6 to 16 years of age. The diagnosis was as follows: leukemias and lymphomas--8, malignant bone tumours--23, malignant brain tumours--8, malignant germinal tumours--10, malignant soft tissue tumours--4, nephroblasoma--4, other neoplasms--3 cases. RESULTS showed the statistically important elevation of protein carbonyl groups' content in children after neoplastic diseases (0.98 +/- 0.31 vs 0.86 +/- 0.19 nmol/mg of protein, p<0.05). The activity of GPx in oncological patients was significantly diminished (20.8 +/- 12.3 vs 25.7 +/- 12,7 U/gHb, p = 0.01), activity of SOD did not differ significantly (2193 +/- 840 vs 1904 +/- 840) compared to the control group.
Conclusion: Children, who have completed oncologic treatment, may have deficits of antioxidant barrier and elevated markers of protein oxidation.