Objective: The primary objective of this study was to compare oxidative DNA damage markers, apoptosis markers and changes in miRNA levels in patients diagnosed with cancer in whom chemotherapy were given. Our secondary objective was also to evaluate tumor responses that can be determined after post-chemotherapy clinical evaluations by phsycial examinations, laboratory results and radiological imagings, and to compare the clinical results to oxidative stress and apoptosis markers and micro RNA levels.
Materials and Methods: To do that we designed a prospective observational cross-sectional study. A total of 34 cancer patients and 27 healthy controls were included in the study from the Harran University School of Medicine Department of Oncology. Newly diagnosed chemotherapy or radiotherapy naive patients without any chronic diseases were included into the study. Patients with a poor perfromance status (ECOG 2 and 3) and patients who did not meet the inclusion criteria were exluded. The cancer patients received chemotherapy according to their scheduled periods. Blood samples were taken from the patients before the first chemotherapy course and before the second chemotherapy round. Patients were called for toxicity control on the 10th day after the chemotherapy. Pre-chemotherapy, post-chemotherapy and control group miR-29a expression levels, change in apoptosis markers and oxidative DNA damage markers were obtained and compared. We studied 8-hydroxy 2-deoxyguanosine, total oxidant status, total anti-oxidant status, and oxidative status index for oxidative stress markers. We studied M30 and M65 as apoptosis markers. Clinical results of efficiency of the chemotherapy was acquired and compared to biochemical markers based on chemotherapy results. Chemotherapy toxicities were recorded.
Results: As a result, we found oxidative DNA damage markers and apoptosis markers were high in the cancer group, demonstrating that oxidative DNA damage and apoptosis might play a direct or indirect role in cancer etiology. However, there were subtle differences between pre-chemotherapy and post-chemotherapy levels. Mir-29a expressions were lower in cancer patients as compared to controls. However, the expression levels were not significantly change in pre- and post-chemotherapy status. Moreover, we found no relationship between clinical status of patients (progression and regression) and studied biochemical markers.
Conclusion: Thus, checking for DNA damage markers and taking precautions to lower the levels of these markers in individuals with cancer risk may be helpful in preventing cancer.