Twenty years of FISH-based translocation analysis for retrospective ionizing radiation biodosimetry

Abstract

Purpose: The fluorescent in situ hybridization (FISH) technique, which easily detects reciprocal translocations, is currently used to estimate doses in retrospective biological dosimetry, after suspected accidental overexposure to ionizing radiation (IR). This study of 42 cases aimed to verify the appropriateness of this assay for radiation dose reconstruction, compared to the dicentric assay, and to evaluate other limitations.

Material and methods: We labeled chromosomes 2, 4, and 12 by 3-color FISH painting to detect translocations on lymphocytes of patients with suspected past IR overexposure.

Result: Translocation dose estimation showed doses significantly different from 0 Gy in 25 of the 42 cases. The lowest positive dose measured was 0.3 Gy. Several months after IR exposure, the doses measured by translocation and dicentric assays are quite similar. For a year, dose estimation by translocation assay becomes more relevant as dicentric frequency starts to decrease, coming close to 0 for more than a year after the exposure. The persistence of translocations enabled us to corroborate an overexposure 44 years earlier. Interpretation of the observed translocation yield requires the knowledge of the patient’s other radiation exposures. A dose assessment by this biomarker is relevant only if the radiation exposure is confirmed.

Conclusions: This technique is appropriate for corroborating a former IR exposure of individuals. When the radiation dose is greater than 1 Gy, the translocations in complex exchanges must be considered. Another relevant point is the use of an appropriate background yield of translocations. The dose assessment, however, also depends on exposure to various genotoxic agents besides IR. If no evidence about the existence of radiation exposure is available, dose assessment is not useful. For this reason, report only the translocation frequency and its comparison with the background yield by age class is preferable.

Keywords:

• FISH
• translocations
• retrospective dosimetry
• lymphocytes
• accidental overexposure
• ionizing radiation

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Notes on contributors

Eric Grégoire

Eric Grègoire, Scientist, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions Accidentelles, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Laurence Roy

Laurence Roy, PhD, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Service de recherche sur les effets biologiques et sanitaires des rayonnements ionisants, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Valérie Buard

Valèrie Buard, Technician, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions mèdicales, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Martine Delbos

Martine Delbos, Technician, CHU Toulouse Purpan, Institut Fèdèratif de Biologie, 31059 Toulouse, France.

Valérie Durand

Valèrie Durand, Scientist, Commissariat à l'Energie Atomique, Bureau des Etudes Biomèdicales chez l'Animal, 92265 Fontenay-aux-Roses, France.

Cécile Martin-Bodiot

Cècile Martin-Bodiot, Technician, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions Accidentelles, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Pascale Voisin

Pascale Voisin, Technician, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions Accidentelles, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Irène Sorokine-Durm

Irene Sorokine-Durm, PhD, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Service Programmes et stratègies Scientifiques, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Aurélie Vaurijoux

Aurèlie Vaurijoux, PhD, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions Accidentelles, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Philippe Voisin

Philippe Voisin, PhD Senior, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Céline Baldeyron

Cèline Baldeyron, PhD, Institut de Radioprotection et de Suretè Nuclèaire (IRSN), Laboratoire de Radiobiologie des expositions Accidentelles, B.P. 17, F-92262 Fontenay-aux-Roses Cedex, France.

Joan Francesc Barquinero

Joan Francesc Barquinero, PhD, Universtitat Autònoma de Barcelona, Facultat de Biociéncies, 08193 Cerdanyola del Vallés, Spain.