Radiation-induced modification of human somatic cells’ chromosome sensitivity to the testing mutagenic exposure of bleomycin in vitro in lung cancer patients in delayed terms following chernobyl accident

The above-background level of cytogenetic effect has been studied using the modified G₂-bleomycin sensitivity assay, the value of which was a marker of hidden chromosome instability (HCI). The following three groups were examined: (1) Chernobyl disaster liquidators (CDLs) (occupational group I), (2) patients with lung cancer (LC) who denied voluntary contact with ionizing radiation (comparative group); and (3) patients with LC participating in the liquidation of the Chernobyl disaster (occupational group 2). Significant interindividual variations in the cytogenetic effects induced by bleomycin and the absence of a positive correlation with the background and above-background frequency of chromosome aberrations have been revealed for all the three groups. It was established that occupational group 2 experienced the highest level of above-background cytogenetic effect and therefore had the highest number of patients with HCI. The data allowed us to hypothesize the existence of an association between a radiation-induced increase in individual susceptibility to testing mutagenic exposure and the development of cancer pathologies in patients exposed to ionizing radiation. The results showed the feasibility of using the G₂-bleomycin sensitivity assay for the examination of irradiated contingents for the detection of HCI as an informative marker of predisposition to cancer.