Genome response to ionizing radiation exposure in a sample of long haul pilots

Full text: In 1990 ICPR accepted definitively that on average flying-crew personnel and pilots are exposed per year, for professional reasons, to ionizing radiation doses 5 to 10 times over that of people at ground level. Although these values are below the level stated by the ICPR as upper risk limit (20 mSv/y), because a number of epidemiological studies evidenced an increase of some specific tumors (among them: melanomas, breast cancer and leukemia) among pilots of different national companies, suspect arises on that these pathologies were a consequence of the over-amount of radiation absorbed for professional reasons. In order to give an answer to this question several studies have been developed in the last two decades, using the analysis of the frequency distribution of the chromosomal aberrations (mainly: dicentric and ring chromosomes and chromatic aberrations) as the most sensitive method to detect the long tern radio-biological damage (bio-dosimetric method). As the result reported in the previous literature are contradictory and thus largely questionable, a new study was performed taking into account some limits of the previous researches and treating to overcome the consequent criticisms. This paper is devoted to report the results obtained in such a study and refers on the cytogenetic and molecular analyses performed in our laboratories on a sample of 32 pilots employed in the national civil airline on long haul routes from at least 7 years. For comparison, a sample of 29 healthy males' donors of comparable age has been taken into account. New evidences on the increase of chromosomal translocations are presented and widely discussed. Furthermore, results obtained in an unusual attempt to study the association between the frequency and the 'category' of the chromosomal aberrations and the presence or absence of specific polymorphisms of genes encoding for some detoxifying enzymes (GSTs family) are also presented and discussed. (author)