Article
Radiation-induced pneumonitis - Identification of high risk groups by analyzing DNA-repair using microgelelectrophoresis (Comet Assay)
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Published: | March 20, 2006 |
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Background: The individual risk to develop a radiation-induced pneumonitis can not be exactly predicted. Co-factors are known, however predictive tests have no clinical importance. The following study analyses, if the individual radiation sensitivity can be better characterized by DNA-repair in peripheral lymphocytes (PL) using microgelectrophoresis (MGE, Comet Assay).
Patients and Methods: PL were isolated from venous blood samples of patients undergoing radiotherapy because of lung cancer (n=37) und of healthy subjects. PL were radiated in vitro (10 MeV; 5 Gy). Aliquots of radiated and non-radiated PL were analysed measuring DNA-strand breaks and alkali-labile areas using MGE (0-120 min. and 24 hrs. after radiation). All patients who survived more than 3 months were evaluated. To quantificate DNA-repair, quotients of median of the Tail Extent Moments (Komet® 4, Kinetic Imaging) were built.
Results: Significant interindividual differences in the frequency of DNA-strand-breaks and DNA-repair were detected. 17 patients demonstrated a RP in the CT. RP was analysed in 100 % of the patients in the group with high radiation sensitivity (>75-percentile), in 82% with medium radiation sensitivity (25-75-perzentile) and in 50 % in the group of low radiation sensitivity.
Conclusion: The Comet-Assay is able to detect interindividual differences of reparation capacity after irradiation und might be a help to assess the individual risk to develop a radiation-induced pneumonitis.