Skeptics question ‘breast cancer-free’ baby claim
Screening gene that carries disease raises troubling issues, expert warns
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A breast cancer-free baby? June 30: TODAY’s Meredith Vieira talks to NBC chief medical editor Dr. Nancy Snyderman about a new technology that could reduce the risk of breast cancer in your baby. Today show |
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The headlines were compelling, holding out a promise that seems to answer every parent’s prayer. Through genetic screening and in vitro fertilization, a British couple had conceived a daughter who would be “cancer free.”
But the claim, NBC medical editor Dr. Nancy Snyderman told TODAY’s Meredith Vieira Monday, is misleading at best. And the screening that was done does not guarantee the child will not get cancer.
“I don’t think ‘guarantee’ is ever smart in medicine,” Snyderman said. She pointed out that the unidentified woman and her husband had used medical science to screen 11 embryos fertilized via the in vitro process for the presence of one gene, called BRCA-1. That gene had triggered breast cancer in the husband’s grandmother, mother, sister and cousin. Women who carry either the BRCA-1 or BRCA-2 gene have a 50 to 80 percent chance of developing breast cancer, usually at a young age.
The couple, who are fertile, underwent the invasive in vitro treatment to ensure that their daughter would not carry the gene. Of the 11 embryos conceived in the lab, five were free of the gene. Two were implanted in the woman, with one becoming a viable fetus.
But, said Snyderman, “There are two problems: You could have [the genes] and never get breast cancer, and there may be other genes that cause breast cancer that she’s not even screened for.”
Sword of Damocles
Despite the high incidence of cancer in women with the BRCA-1 and BRCA-2 genes, they account for only five percent of all breast cancers, she said.
“Damocles’ sword is still hanging over her head, as for every woman. She can still get breast cancer — just not this specific kind,” Snyderman told Vieira.
There are moral and ethical issues associated with such screening. Some people believe it is not morally acceptable to destroy viable embryos just because they carry a gene that may cause cancer.
For years, there has been screening through procedures such as amniocentesis for such birth defects as Down syndrome. Women are given the option of aborting the pregnancy or going ahead with the birth, according to their personal beliefs.
Genetic screening is simply the next step in that process, Snyderman said. What we still have to deal with are the destinations to which genetic technology will eventually lead.
There is no stopping the science, Snyderman said. “Science will always win. What we have to come to grips with in society is these moral and ethical questions should be in tandem with the science,” she told Vieira.
Already, Snyderman said, there are labs around the world that will select embryos for certain characteristics: “The science is available for you to say ‘I only want a boy, and I want a tall boy, and I’d like this eye color.’ ”
The future is here
It’s not science fiction. “We’re there,” she continued. “You can go to some countries and offshore labs and absolutely start to tinker with the genetics of what you want. We already know that cloning is taking place.”
Some people may see it as a black-or-white issue. Most, Snyderman said, will see it in shades of gray.
“Screening for illness, terminal illness or perhaps terrible neurological problems — some people may say, ‘That’s the gray line for me. I’m willing to go there,’ ” she told Vieira. “Your gray line might be black-and-white to someone else. But the science absolutely will be there.”
Where Snyderman has a problem is with the suggestion that screening such as that the British couple underwent “guarantees” a disease-free baby, or even one that will grow up to be a healthy and happy adult. You can screen for everything, but the child can still get hit by a bus.
“The guarantee in medicine — I have a real issue with that,” Snyderman concluded. “You cannot guarantee a healthy child no matter what. There’s always going to be something else that might befall one of our children.”
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