Serum 8‐Oxo‐dG as a Predictor of Sensitivity and Outcome of Radiotherapy and Chemotherapy of Upper Gastrointestinal Tumours

Abstract

The level of oxidative stress is important in the initiation and progression of various age-related diseases, such as cancer. The level of oxidative stress may also play a significant role in cancer patients' response to treatment. We aimed to investigate whether serum 8-oxo-dG as a marker of oxidative stress is a predictor of tumour response. We used modified ELISA with a two-step filtration to analyse 8-oxo-dG in serum. The relationship between 8-oxo-dG levels, tumour response, and toxicity was studied in 19 oesophageal cancer patients who received radiotherapy and 16 gastric cancer patients who received chemotherapy. In the radiotherapy and the merged radio- and chemotherapy groups, the baseline levels of 8-oxo-dG were significantly lower in responder patients than in nonresponder patients and the increments after treatment were greater. In comparison with patients whose serum 8-oxo-dG levels decrease after treatment, patients with increasing levels had a longer median “progression-free survival.” Our results, although preliminary, suggest that serum levels of 8-oxo-dG may potentially be used to predict the sensitivity and outcome of radiotherapy and chemotherapy of upper gastrointestinal tumours. Patients with 8-oxo-dG levels that are low prior to treatment and subsequently increase after treatment may be more likely to benefit from the therapy.

PINK1-parkin pathway of mitophagy protects against contrast-induced acute kidney injury via decreasing mitochondrial ROS and NLRP3 inflammasome activation

“…8A and B). Other researchers have demonstrated that ROS directly induced DNA oxidative damage [[27], [28], [29]], and we also found using immunofluorescence that 8-OHdG had the same trend as mitochondrial ROS (Fig. 8A and C).…”

Biochemical basis and metabolic interplay of redox regulation

“…For the aromatic compounds (DNA/RNA), OH • can be added directly to produce hydroxylated radical adducts. These stable adducts such as 8-Oxo-deoxyguanosine [41,42] can be detected at extremely low concentration and used as a biomarker of OH • . When reacting with anions, OH • takes an electron, producing a corresponding new radical.…”

Association between clinicopathological features of breast cancer with adipocytokine levels and oxidative stress markers before and after chemotherapy

“…One of the most frequently studied markers of oxidative DNA damage is the production of 8-oxo-dG, when ROS reacts with guanine bases in DNA ( 71 ). Several studies have shown that oxidative stress levels, based on 8-oxo-dG levels in urine or blood serum, may be a useful biomarker for determining the response to radiotherapy and chemotherapy in cancer patients ( 33 ). In most cases, chemotherapy accompanied by ROS overproduction results in elevated levels of 8-oxo-dG in patients with various types of cancer ( 72 , 73 ).…”

“…High levels of 8-oxo-dG in tumors, blood samples or urine have been found in patients with various types of cancer ( 30 , 31 ). Moreover, 8-oxo-dG may be useful for predicting prognosis in different types of cancer ( 32 , 33 ). ROS levels are maintained within narrow limits under physiological conditions by an antioxidant defense system consisting of multiple independent components ( 34 ).…”