DNA damage, repair of single strand breaks, total antioxidant capacity and reduced glutathione levels in female patients with a family history of cancer

Introduction Oxidative DNA damage, a biomarker used in peripheral blood studies related to cancer and other diseases, may be modulated by plasma antioxidant capacity (TAC), the levels of reduced glutathione (GSH) and the DNA repair ability. Objectives To determine endogenous and oxidative DNA damage, lymphocyte DNA repair capacity against hydrogen peroxide, plasma levels of TAC and GSH in female patients with a family history of cancer. Methods We studied 40 patients (38,9 ± 14,6 years) and 21 healthy women (39.4 ± 12.5 years). The alkaline comet assay was used for determination of markers of DNA damage and repair ability. Total antioxidant capacity and plasma glutathione levels were determined by spectrophotometric methods. Results Endogenous and oxidative DNA damage were increased 1.5 and 1.3 times in patients, although without statistical significance. Residual DNA damage after challenging cells with hydrogen peroxide was increased 1.2 times in this group, reflecting a lower efficiency of DNA repair, but without statistical significance. Plasma levels of GSH were significantly elevated in patients, whereas plasma TAC was not significantly modified. Conclusions: Patients showed a tendency for genomic instability that could be modulated by an increase in plasma GSH levels. These markers could be used in clinical follow-up of patients with genetic risk of developing cancer.