X-rays and radioactive particles may alter DNA and cause cancer?

Emobileclinic Researchers Corner 

Researchers show how ionising radiation damages DNA and causes cancer
The Nature Communications has published the work of researchers from the Wellcome Trust Sanger Institute and their collaborators who have found two characteristic patterns of DNA caused by ionizing radiation in human cancers. This discovery will enable medical doctors to pinpoint which tumours have been caused by radiation  and to enable doctors to identify and investigate which tumours needed to be treated differently as well as helping to explain how radiation can cause cancer.

While it generally believed that ionising radiation, such as gamma rays, X-rays and radioactive particles can cause cancer by damaging DNA, however, no study has shown how this occurs, or state the number of tumours caused by radiation damage.

Earlier study on cancer had revealed that DNA damage often leaves a molecular fingerprint, known as a mutational signature, on the genome of a cancer cell. The researchers searched for mutational signatures in 12 patients with secondary radiation-associated tumours in comparism with 319 that had not been exposed to radiation.

Dr Peter Campbell who led the study, said: “To find out how radiation could cause cancer, we studied the genomes of cancers caused by radiation in comparison to tumours that arose spontaneously. 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.”

Dr Sam Behjati, clinician researcher said: “Ionising radiation probably causes all types of mutational damage, but here we can see two specific types of damage and get a sense of what is happening to the DNA. Showers of radiation chop up the genome causing lots of damage simultaneously. This seems to overwhelm the DNA repair mechanism in the cell, leading to the DNA damage we see.”

Professor Adrienne Flanagan, a collaborating cancer researcher from University College London and Royal National Orthopaedic hospital, said: “This is the first time that scientists have been able to define the damage caused to DNA by ionising radiation. 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.”

Source
S. Behjati and G. Gundem et al (2016): Mutational signatures of ionizing radiation in second malignancies,., Nature Communications, doi:10.1038/ncomms12605