Radiation from the Chernobyl disaster raised the risk of specific mutations linked to thyroid cancer. However, it did not introduce new mutations in the DNA of children born to parents who helped clean up the site.
Scientists have delved into the genetic aftermath of the Chernobyl disaster—the worst nuclear accident in history. One team examined genetic alterations in thyroid tumors from those exposed to radioactive iodine. Another investigated the children of cleanup workers, known as liquidators.
Epidemiological studies confirm that Chernobyl exposure heightened the risk of papillary thyroid carcinoma. While radiation is known to damage DNA, the exact mechanisms have been elusive.
In this landmark study, researchers analyzed thyroid carcinoma tissues from the Chernobyl Tissue Bank. They compared genomes from 359 individuals exposed before adulthood to those from people in the same region born over nine months post-accident (unexposed).
Findings showed that higher radiation doses correlated with elevated double-stranded DNA breaks in tumors—where both DNA strands fracture at the same site. Cells have repair mechanisms for these, but the tumors also displayed errors in those processes.
"These errors aren't exclusive to radiation-induced cancers," explains Stephen Chanock, PhD, from the U.S. National Cancer Institute (NCI) and lead author. "The same mutations appear in unexposed patients' tumors, just at lower frequencies."
A second study probed potential multigenerational impacts of radiation exposure.
It sequenced the genomes of 130 children born between 1987 and 2002 to liquidators—those who responded from April 26, 1986, onward, including long-term remediation teams.
Focus was on de novo mutations: new genetic changes in the child absent from parents' DNA.
An increase would indicate parental germ cell damage from radiation. Instead, rates matched the natural average of 50–100 per generation. "Even those with very high radiation doses did not transmit extra mutations," notes Chanock. "Any effect is subtle and rare."
These insights advance our understanding of radiation-linked thyroid cancer and offer reassurance to Fukushima survivors considering parenthood.
