The Association between Hypermethylation of Gene Promoters and Cytogenetic Disturbances in Humans Exposed to Radiation as a Result of the Chernobyl Accident.

The estimation of hypermethylation of the cell cycle (RASSF1A, p16/INK4A, p14/ARF) and detoxification (GSTP1) gene promoters was carried out in blood leukocytes of humans exposed to radiation as a result of the Chernobyl accident (98 individuals: accident liquidators, 76 individuals; adult residents of the territories with radionuclide contamination, 135–688 kBq/m2, 22 individuals) depending on their cytogenetic status. The results of multiple regression analysis ("Frequency of aberrations ~ age + number of hypermethylated genes") indicate a correlation of the total level of chromosomal type aberrations with the considered epigenetic disturbances (β = 0.256; р = 0.011), but not with age (β = –0.138; p = 0.165). The frequency of these cytogenetic disorders increases with an increase in the number of methylated loci. Thus, a positive association between the damages to the genome induced by radiation exposure in the range of small and medium doses (long time ago) and hypermethylation of promoters of the genes of the main protective systems of the cells was detected. [ABSTRACT FROM AUTHOR]