The last decade witnessed an increase in the use of comet assay for DNA damage monitoring in cancer patients and controls. Apart from case-control studies, reports described the determination of DNA damage prior to (baseline value) and after chemo-/radiotherapy, the treatment resulted in significantly elevated DNA damage. However, studies on DNA damage as a factor reflecting cancer prognosis and therapy prediction are scarce. In most cases, DNA damage was analysed in surrogate tissues. The data on DNA damage are available for 17 types of cancer. The reviewed data unambiguously pinpoint the usefulness of the comet assay in human cancer research due to its sensitivity and cost-effectiveness in evaluating DNA damage associated with the disease and with the treatment. DNA repair capacity (DRC) represents a complex marker for functional evaluation of multigene DNA repair processes in cancer onset with future prospects in personalized prevention and/or cancer treatment. A comparison between studies and more general conclusions are precluded by a variable design of the studies and a lack of standard protocol for both DNA damage and DRC determination. Since cancer is a heterogeneous complex disease, numerous points have to be considered: a) DNA damage and DRC measured in surrogate/target tissues, b) changes in the levels of DNA damage and DRC may be a cause or a consequence of the disease, c) changes in DRC alter sensitivity of tumour cells to antineoplastic drugs, d) one time point-sampling of patients provides insufficient information on the role of DNA damage and its repair in carcinogenesis. Finally, systemic cancer therapy is targeted at DNA damage and its repair. A proper understanding of these processes is a key precondition for the optimisation of therapy regimens, prediction of therapeutic response and prognosis in cancer patients.

Department of Molecular Biology of Cancer Institute of Experimental Medicine of the Czech Academy of Sciences Videnska 1083 142 20 Prague Czech Republic; Institute of Biology and Medical Genetics 1st Faculty of Medicine Charles University and General University Hospital Prague Albertov 4 128 00 Prague Czech Republic; Biomedical Center Faculty of Medicine in Pilsen Charles University Alej Svobody 76 323 00 Pilsen Czech Republic

Department of Molecular Biology of Cancer Institute of Experimental Medicine of the Czech Academy of Sciences Videnska 1083 142 20 Prague Czech Republic; Institute of Biology and Medical Genetics 1st Faculty of Medicine Charles University and General University Hospital Prague Albertov 4 128 00 Prague Czech Republic; Department of Medical Genetics 3rd Faculty of Medicine Charles University Ruska 2411 87 100 00 Prague Czech Republic

References provided by Crossref.org

Editorial: Current understanding of genomic and chromosomal instabilities in solid malignancies

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases MUTYH and hOGG1 in Colorectal Cancer Patients

The Interactions of DNA Repair, Telomere Homeostasis, and p53 Mutational Status in Solid Cancers: Risk, Prognosis, and Prediction

DNA Repair and Ovarian Carcinogenesis: Impact on Risk, Prognosis and Therapy Outcome

Oxidative Damage in Sporadic Colorectal Cancer: Molecular Mapping of Base Excision Repair Glycosylases in Colorectal Cancer Patients