Researchers found mutational signatures which appear to indicate changes to DNA caused by exposure to ionizing radiation, which may allow doctors to better treat cancer caused by non-spontaneous mutations. Photo by Constantin-Ciprian/Shutterstock
LONDON, Sept. 13 (UPI) -- Though scientists have suspected ionizing radiation can cause cancer, experiments conducted in England are the first to show the damage it inflicts on DNA and may allow doctors to identify tumors caused by radiation.
In a study published in the journal Nature Communications, scientists showed the effects of gamma rays, X-rays and radioactive particles on DNA, deciphering patterns they think will help differentiate between spontaneous and radiation-caused tumors, allowing for better cancer treatment.
"To find out how radiation could cause cancer, we studied the genomes of cancers caused by radiation in comparison to tumors that arose spontaneously," Dr. Peter Campbell, a researchers at the Wellcome Trust Sanger Institute, said in a press release. "By comparing the DNA sequences we found two mutational signatures for radiation damage that were independent of cancer type. We then checked the findings with prostate cancers that had or had not been exposed to radiation, and found the same two signatures again. These mutational signatures help us explain how high-energy radiation damages DNA."
For the study, the researchers looked for mutational signatures in 12 cancer patients with radiation-associated second malignancies, and compared their tumors to 319 from patients not exposed to radiation.
The researchers found two mutational signatures they link to radiation. While one causes small deletions of DNA bases, the other -- called a balanced inversion -- includes two cuts to DNA, with the middle piece spinning around and rejoining in the opposite direction.
These mutations, especially balanced inversions, which do not happen naturally in the body, increase the potential for cancer to develop, the researchers say.
"This is the first time that scientists have been able to define the damage caused to DNA by ionising radiation," said Adrienne Flanagan, a professor at the University College London Cancer Institute. "These mutational signatures could be a diagnosis tool for both individual cases, and for groups of cancers, and could help us find out which cancers are caused by radiation. Once we have better understanding of this, we can study whether they should be treated the same or differently to other cancers."