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 and
treated through chemotherapy. Our secondary objective was also to evaluate tumor responses that
can be determined after post-chemotherapy clinical evaluations by physical 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 performance status (ECOG 2 and 3) and patients who did not meet the inclusion
criteria were excluded. 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 postchemotherapy
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.