title: Three somatic genetic biomarkers and covariates in radiation-exposed Russian cleanup workers of the chernobyl nuclear reactor 6-13 years after exposure.
abstract: Three somatic mutation assays were evaluated in men exposed to low-dose, whole-body, ionizing radiation. Blood samples were obtained between 1992 and 1999 from 625 Russian Chernobyl cleanup workers and 182 Russian controls. The assays were chromosome translocations in lymphocytes detected by FISH, hypoxanthine phosphoribosyltransferase (HPRT) mutant frequency in lymphocytes by cloning, and flow cytometic assay for glycophorin A (GPA) variant frequency of both deletion (N/Ø) and recombination (N/N) events detected in erythrocytes. Over 30 exposure and lifestyle covariates were available from questionnaires. Among the covariates evaluated, some increased (e.g. age, smoking) and others decreased (e.g. date of sample) biomarker responses at a magnitude comparable to Chernobyl exposure. When adjusted for covariates, exposure at Chernobyl was a statistically significant factor for translocation frequency (increase of 30%, 95% CI of 10%-53%, P = 0.002) and HPRT mutant frequency (increase of 41%, 95% CI of 19%-66%, P < 0.001), but not for either GPA assay. The estimated average dose for the cleanup workers based on the average increase in translocations was 9.5 cGy. Translocation analysis is the preferred biomarker for low-dose radiation dosimetry given its sensitivity, relatively few covariates, and dose-response data. Based on this estimated dose, the risk of exposure-related cancer is expected to be low.
authors.affiliation: Biology and Biotechnology Research Program, Lawrence Livermore National Laboratory, California 94550, USA. jones20@llnl.gov
authors.forename: Irene M
authors.initials: IM
authors.lastname: Jones
authors.forename: Heather
authors.initials: H
authors.lastname: Galick
authors.forename: Paula
authors.initials: P
authors.lastname: Kato
authors.forename: Richard G
authors.initials: RG
authors.lastname: Langlois
authors.forename: Mortimer L
authors.initials: ML
authors.lastname: Mendelsohn
authors.forename: Gloria A
authors.initials: GA
authors.lastname: Murphy
authors.forename: Pavel
authors.initials: P
authors.lastname: Pleshanov
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Ramsey
authors.forename: Cynthia B
authors.initials: CB
authors.lastname: Thomas
authors.forename: James D
authors.initials: JD
authors.lastname: Tucker
authors.forename: Ludmila
authors.initials: L
authors.lastname: Tureva
authors.forename: Irina
authors.initials: I
authors.lastname: Vorobtsova
authors.forename: David O
authors.initials: DO
authors.lastname: Nelson
mesh_terms: D000328:Adult; D015415:Biomarkers; D005434:Flow Cytometry; D006021:Glycophorins / Q000235:genetics*; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016273:Occupational Exposure; D011210:Power Plants; D011829:Radiation Dosage; D018788:Radioactive Hazard Release; D013997:Time Factors; D014178:Translocation, Genetic; D014455:Ukraine
chemical_list: D015415:Biomarkers; D006021:Glycophorins; D007041:Hypoxanthine Phosphoribosyltransferase