Cancer Mystery

Furthermore, radiation damage is not always proportional to the amount of radiation experienced. "Our research shows some unusual things," says Dicello. Some types of chromosome aberrations are very sensitive to radiation. "Deliver a low dose, and they take off." Other types of aberrations require much higher doses. Researchers are still trying to sort out which is which … and why?

These uncertainties make it hard to predict how human tissue will react to space radiation. Astronauts, points out Dicello, will encounter at least two kinds of radiation: (1) high-energy cosmic rays from distant exploding stars and (2) less-energetic protons and photons from flares on our own sun -- and they can be exposed to both at the same time.

more Cancer specialist Dr. John Dicello

While researchers know something about how cells respond to each kind of radiation separately, some of Dicello's work suggests that exposure to these two types of radiation mixed together could produce as-yet unpredictable results.

The damage could be less than the two kinds added together - or it could be more! There could, perhaps, be an adaptive response in which lightweight solar protons stimulate repair processes to help reduce the effects of the heavy cosmic ray ions. Or something totally unexpected could happen.

There's still a lot to learn. Dicello lists some of the questions: "How important is adaptive response? How important is the effect of cells on each other? How important are antioxidants? We don't yet know."

"The answers are important to everyone," he adds. Understanding how the body deals with damaged DNA could help doctors prevent complications from the radiation treatments given to cancer patients. It might help them deal with the fallout from, say, a terrorist's dirty bomb or DNA-problems caused by environmental or chemical pollution.

Eventually, Dicello believes, researchers will figure it out. And when that happens, people on Earth will benefit at least as much as people in space…

…who can then turn to lesser worries, like double-jawed aliens.