Roger Highfield writes in the Telegraph (U.K.) newspaper that it may be dangerous for cancer survivors to have children, since the genetic changes caused by radiation and chemotherapy can be passed down to their children and grandchildren, putting them at greater risk of developing cancer.
Researcher Dr. Yuri Dubrova has discovered that this happens with mice, and he now wants to look at statistics to see if there's evidence that this happens with human beings. "I am uncomfortable with extrapolating our results," he says. "?The mouse data are not enough to change our perception. We are desperate for human data.''
It's already known that radiation therapy can alter the genetic makeup of the individual being treated. Earlier studies have found no inherited mutations, or cancers, among human families that were exposed to high levels of radiation, such as those at Hiroshima or Chernobyl. But Dubrova has found a more subtle problem. Radiation seems to affect the "eraser" used by cells in the body to correct genetic errors. This results in "genomic instability," which gives tumors the ability to quickly adapt and change, making them less vulnerable to body defenses or to drugs.
When male mice were exposed to high levels of radiation, these genetic mutations were passed on to their offspring, even when the offspring had not been exposed to the radiation and the mother wasn?t irradiated. This higher mutation rate persisted in the grandchildren of the mice. "We were absolutely surprised," Dubrova says. "When you go to the second generation you see the same level of instability that you see in the first generation of offspring."
He expects to find evidence of this happening in humans and says, "I don't think there is a great deal of difference between humans and mice, frankly. At a first glance we do differ. But looking closely at biology, DNA repair, damage and genome size, we are pretty similar.''
If you get cancer, will your doctor warn you about this danger?
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