Researchers from the University of Cambridge found even low doses of radiation promoted the spread of cancer-capable cells in healthy tissue. The report published in the journal Cell Stem Cell showed how the equivalent of just three CT (computed tomography) scans made cells in the esophagus of mice “cancer-ready.”
CT scans are thought to be safe by the medical community because the radiation does not damage DNA. However, scientists discovered in this study the scans altered healthy cells making them “cancer-capable,” meaning cancer is more possible.
The radiation created what are known as p53 mutations in the cells. That’s what makes them more likely to become cancerous.
Previous research revealed how normal tissue is a combat zone where mutant cells compete for space with healthy cells. Scientists say everyone has cancer-capable mutant cells like p53 mutations in healthy tissue and they increase as we age. However, very few go on to form cancer.
What the radiation did in the study was to change the balance of power in favor of the mutant cells. It resulted in the p53 cells spreading to overtake the healthy cells.
"Our bodies are the set of 'Game of Clones' - a continuous battle for space between normal and mutant cells,” said Dr. David Fernandez-Antoran. “We show that even low doses of radiation, similar to three CT scans' worth, can weigh the odds in favor of cancer-capable mutant cells. We've uncovered an additional potential cancer risk as a result of radiation that needs to be recognized."
The good news is an over-the-counter antioxidant given to the mice before radiation bolstered healthy cells enough to combat the mutant cells. Scientists gave some mice N-Acetyl Cysteine (NAC) with the same level of radiation and found it gave the normal cells enough of a boost to eradicate the p53 mutant cells. But researchers said the antioxidant alone without the exposure to radiation had no bearing on the turf war between the normal and mutant cells.
"Giving mice an antioxidant before exposing them to low doses of radiation gave healthy cells the extra boost needed to fight against the mutant cells in the esophagus and make them disappear,” said Dr. Kasumi Murai. “However, we don't know the effect this therapy would have in other tissues—it could help cancer-capable cells elsewhere become stronger."
“This research is helping us understand more about the effects of low doses of radiation and the risks it may carry,” said Professor Phil Jones. “More research is needed to understand the effects in people."