Altered Levels of Salivary 8-oxo-7-hydrodeoxyguanosine in Breast Cancer

Oxidative stress has been implicated in the pathogenesis of breast cancer (BC). To determine whether BC is associated with altered salivary redox homeostasis, we performed a case-control study assessing the relationship between BC and 8-oxo-7-hydrodeoxyguanosine (8-oxodG), a marker for oxidative damage to DNA. Enzyme-linked immunosorbent assay for 8-oxodG was used on whole, unstimulated saliva of 134 BC patients and 226 healthy controls. Associations of the redox data were assessed by analysis of variance and logistic regression analysis. Our results revealed that there were 1) significantly lower mean levels of salivary 8-oxodG in BC patients versus controls (P = 0.0005), 2) significantly lower levels among participants who did not receive radiotherapy and/or chemotherapy as compared with controls (P < 0.0001), 3) significantly lower levels among BC patients who did not receive these treatments than among those who did (P < 0.02), 4) and no significant differences in mean 8-oxodG levels among BC patients...