Expression of DNA repair genes in association with ionizing radiation Radiation and DNA repair

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Amaury Machi Jr
Matheus Moreira Perez
Glaucia Luciano da Veiga
Edimar Cristiano Pereira
Fernando Adami
Beatriz Alves
Fernando Fonseca


radiology, DNA repair, DNA damage, MutS


Background and aim: DNA repair systems are functionally essential for the maintenance of life and among these, we can highlight the MutS system, subdivided into MutSα (hMSH2 and hMSH6) and MutSβ (hMSH2 and hMSH3). The objective of this study was to analyze the expression of hMSH2 and hMSH6 repair genes in radiology technicians exposed to low radiation doses.

Methods: Thirty workers occupationally exposed to ionizing radiation and twenty-five non-exposed were included in this study. Gene expression was analyzed by qPCR. Peripheral blood samples were collected from both groups for total RNA isolation.

Results: It was observed a five-fold increase (p=0.006) in the hMSH2 repair gene expression in those exposed to radiation and a weak but significant correlation (p=0.041) with the hMSH6 genes when we associated the number of hours of exposure with gene expression.

Conclusions: The longer the exposure time, the greater the activation of this component of the repair system. Application to Practice: Blood count parameters could did not alter with radiation exposure. X-rays used by radiology technicians in imaging tests can damage the DNA to the point of activating the MutS repair system and that there is a greater tendency of expression of this system in professionals that had undergone longer exposure. 


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1. Tubiana M, Feinendegen LE, Yang C, et al. The linear no-threshold relationship is inconsistent with radiation biologic and experimental data. Radiology 2009; 251(1):13- 22.

2. NCRP (National Council on Radiation Protection and Measurements). Radiation exposure of the US population from consumer products and miscellaneous source. 95th ed. The Council, 1987.

3. UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), 2006. Epidemiological studies of radiation and cancer. In: United Nations Scientific Committee on the Effects of Atomic Radiation. Report. Annex A. Epidemiological Studies of Radiation and Cancer. New York: United Nations, 2008 13-322. Available at:<> Accessed on 20 april 2020.

4. Kitahara CM, Linet MS, Rajaraman P, et al. A new era of low-dose radiation epidemiology. Curr Environ Health Rep 2015; 2(3): 236-49.

5. NRC (National Research Council), 2006. Health Risks from Exposure to Low Levels of Ionizing Radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press. Available at:<> Accessed on 10 Jun 2019.

6. Frieben A. Demonstration eines cancroids des rechten handruckens, das sich nach langdaurernder einwirkung von roentenstrahlen enwickelt hatte. Fortschr Roentgenstr 1902; 6: 106–11.

7. Kathren RL. Pathway to a paradigm: the linear no-threshlod dose response model in historical context. Health Phys 1996; 70: 621-35.

8. Sancar A, Lindsey-Boltz LA, Unsal-Kaçmaz K, et al. Molecular mechanism of mammalian DNA repair and the DNA damage checkpoints. Annu Rev Biochem 2004; 73: 39-85.

9. Tong WM, Cortes U, Hande MP, et al. Synergistic role of Ku80 and poly (ADP– ribose) polymerase in suppressing chromosomal aberrations and liver cancer formation. Cancer Res 2002; 62: 6990-6.

10. Swanson RL, Morey NJ, Doetsch PW, et al. Overlapping specificities of base excision repair, nucleotide excision repair, recombination and translesion synthesis pathways for DNA base damage in Saccharomyces cerevisiae. Mol Cell Biol 1999; 19: 2929-35.

11. Harrington JM, Kolodner RD. Saccharomyces cerevisiae Msh2-Msh3 acts in repair of base-base misrepair. Mol Cell Biol 2007; 27: 6546-54.

12. UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation), 2012. Biological mechanisms of radiation actions at low doses. A white paper to guide the scientific committee’s future programme of work. Available at:<> Accessed on 24 may 2019.

13. Pfaffl MW. A new mathematical model for relative quantification in real-time RT-PCR. Nucleic Acids Res 2001; 29: e45.

14. Tubiana M. Dose-effect relationship and estimation of the carcinogenic effects of low doses of ionizing radiation: the joint report of the Académie des Sciences (Paris) and of the Académie Nationale de Médecine. Int J Radiat Oncol Biol Phys 2005; 63: 317-9.

15. Wilson TM, Ewel A, Duguid JR, et al. Differential cellular expression of the human MSH2 repair enzyme in small and large intestine. Cancer Res 1995; 55: 5146-50.

16. Martin LM, Marples B, Coffey M, et al. DNA mismatch repair and the DNA damage response to ionizing radiation: making sense of apparently conflicting data. Cancer Treat Rev 2010; 36: 518-27.

17. NRSB - Committee to assess health risks from exposure to low levels of ionizing radiation; Nuclear and Radiation Studies Board, Division on Earth and Life Studies, National Research Council of the National Academies. Health risks from exposure to low levels of ionizing radiation: BEIR VII Phase 2. Washington, DC: The National Academies Press, 2006.

18. Budworth H, Snijders AM, Marchetti F, et al. DNA repair and cell cycle biomarkers of radiation exposure and inflammation stress in human blood. PLoS One 2012; 7: e48619.

19. Liu JJ, Freedman DM, Little MP, et al. Work history and mortality risks in 90 268 US radiological technologists. Occup Environ Med 2014; 71: 819-35.

20. Preston DL, Kitahara CM, Freedman DM, et al. Breast cancer risk and protracted low-to-moderate dose occupational radiation exposure in the US Radiologic Technologists Cohort, 1983-2008. Br J Cancer 2016; 115: 1105-1112.

21. Valverd NJ. Radiações Ionizantes. In: Patologia do Trabalho. São Paulo: Atheneu, 2005.