Increased cancer risk as a genetic effect of ionizing radiation.

The well known genetic effects of ionizing radiation include severe developmental disorders in the progeny of irradiated parents resulting in embryonic death, stillbirth and early postnatal mortality, congenital abnormalities, malformations and fertility disturbances in live-born organisms. These effects are considered to be due to gross mutations (genomic, chromosomal and those of essential genes). Physiological inferiority and an increased cancer risk in phenotypically normal offspring of irradiated parents appear to be two further types of genetic effect of radiation. The genetic background of these effects is suggested to be induced recessive polygene mutations and regulatory DNA alterations, which may lead to instability of the hereditary apparatus of cells, activation of protooncogenes and other inducible processes. A comparison of somatic and genetic effects of radiation shows certain similarities, not only in phenomenology, but probably also in pathogenetic mechanisms.