Somatic copy number variations as long-term genomic biomarkers of ionizing radiation exposure in individuals accidentally exposed to Cesium-137 during the Goiânia radiological accident.

INTRODUCTION

Ionizing radiation (IR) is a well-established mutagen capable of inducing structural genomic alterations. The 1987 Goiânia radiological accident involving Caesium-137 represents one of the most significant cases of accidental human exposure to IR outside nuclear facilities.

OBJECTIVE

This study aimed to investigate the occurrence of somatic copy number variations (CNVs) as potential biomarkers of IR exposure in individuals accidentally exposed to Cesium-137.

METHODS

A case-control study was conducted including 20 exposed and 25 non-exposed individuals. Chromosomal microarray analysis (CMA) using the GeneChip® CytoScan HD platform was applied to detect autosomal CNVs. Statistical analyses included ANOVA, linear regression, and odds ratio estimation to assess dose-response relationships and associations with age.

RESULTS

Exposed individuals exhibited a 33.6% overall increase in CNV burden compared with controls, with CNV losses rising by 70% and gains by 46%. Linear regression revealed a positive dose-response relationship, with each 1 Gy of absorbed dose increasing CNV losses and gains by 0.65 and 0.58 lnCNV units, respectively. Age and radiation dose jointly influenced CNV frequency. Chromosome 10 showed the highest CNV density, and deletions predominated over duplications.

CONCLUSION

The findings demonstrated that somatic CNVs persist as quantifiable genomic signatures of ionizing radiation exposure even decades after the event. CNV profiling represents a promising tool for retrospective biodosimetry and long-term health surveillance of exposed populations, reinforcing its potential role in radiological protection and genomic risk assessment frameworks.