Cancer-capable cells given ‘advantage’ by low doses of radiation, Sanger Institute study shows
Cells capable of becoming cancerous are given a competitive advantage over normal cells in healthy tissues by low doses of radiation equivalent to three CT scans, scientists have found.
The researchers at the Wellcome Sanger Institute and University of Cambridge studied the effects of low doses of radiation in the oesophagus of mice.
They found it increased the number of cells with mutations in p53, a genetic change associated with cancer. Giving the mice an antioxidant before radiation promoted the growth of healthy cells, however, which outcompeted and replaced the p53 mutant cells.
The study, published in Cell Stem Cell, recommends that the risk should be considered when assessing radiation safety and also suggests the potential of creating non-toxic preventative measures to cut the risk of developing cancer by helping our healthy cells to eradicate cancer-capable ones.
Dr David Fernandez-Antoran, first author from the Wellcome Sanger Institute, said: “Our bodies are the set of ‘Game of Clones’ – a continuous battle for space between normal and mutant cells. We show that even low doses of radiation, similar to three CT scans’ worth, can weigh the odds in favour of cancer-capable mutant cells. We’ve uncovered an additional potential cancer risk as a result of radiation that needs to be recognised.”
Low doses of radiation, such as the exposure from medical imaging, are considered safe because they cause little DNA damage and apparently minimal effect on long-term health.
Other effects of exposure to low levels of radiation have remained hidden until now, meaning that assessing the associated risk has been difficult.
Professor Phil Jones, lead author from the Wellcome Sanger Institute and MRC Cancer Unit, University of Cambridge, said: “Medical imaging procedures using radiation, such as CT scans and x-rays, have a very low level of risk – so low that it's hard to measure. This research is helping us understand more about the effects of low doses of radiation and the risks it may carry. More research is needed to understand the effects in people.”
Dr Kasumi Murai, an author from the Wellcome Sanger Institute, said it is not know if the antioxidant therapy would work in other tissues, or even have the reverse effect, adding: “What we do know is that long term use of antioxidants alone is not effective in preventing cancer in people, according to other studies.”