Stanford University on Tuesday announced plans to create new types of embryonic stem cells that might require its researchers to eventually attempt a form of cloning human embryos.
The announcement came as the Palo Alto-based university said it had created a new research institute devoted to using stem cells to study disease, funded initially by an anonymous $12-million donation.
Stem cells from embryos are a type of biological "blank slate," able to copy themselves indefinitely and turn into every other type of cell in the human body. By studying how stem cells accomplish this, scientists believe they can understand how cancer cells grow wildly into tumors, and other mechanisms of disease.
Dr. Irving Weissman, director of the new Institute for Cancer/Stem Cell Biology and Medicine, said one of his goals is to overcome a shortcoming in most of the embryonic stem cell lines available today. Most stem cells have been taken from embryos created at fertility clinics, and scientists have no specific information about the genes in those embryos or in the stem cells they produce.
Instead, Weissman wants to produce embryonic stem cells that carry specific genetic mutations linked to certain diseases.
One line of stem cells, for example, might contain the BRCA1 genetic mutation that has been linked to breast cancer. As the stem cells transform themselves into breast tissue, scientists would track the activity of the faulty gene to glean clues to how cancer arises.
Other cells might be created that carry the faulty genes linked to diabetes, Parkinson's disease and other ailments.
The trick, Weissman said, is to find the best way to produce these embryonic stem cells.
Weissman's preference, he said, would be to conduct a kind of genetic swap on existing stem cells. A stem cell could be stripped of its nucleus, which carries its genes. Then, researchers could insert a nucleus from someone known to carry the BRCA1 mutation or other genetic flaws. A group in Australia is already trying this technique, Weissman said.
But if that method fails, Weissman said he would not rule out trying a controversial technique that many people consider to be a form of human cloning.
In this alternate method, a human egg cell would be stripped of its genes and given DNA from a different person. The result would be an egg from one person with the genes of another. The egg would divide into an embryo, and stem cells would be taken from the embryo.
This technique is controversial because it involves creating and then destroying a human embryo. Moreover, the embryo theoretically could be implanted into a woman and become a child -- a clone of the person who donated a nucleus to the egg cell.
President Bush has called for a ban on this technique, even in disease research. Congress probably will consider the ban next year.
Weissman said that before trying cloning, institute scientists would conduct extensive work in mice to determine if other methods are preferable.
Cloning cannot be done with federal funds. Cloning experiments would have to win approval from a Stanford ethics review board, "and they would have to say, 'This is the reason I want to do this. This is my belief of the costs and benefits, the risks and benefits,' " Weissman said. "I would not be surprised if someone we hired would eventually do this."
While cloning has drawn sharp opposition from antiabortion groups and others, some of those critics said Tuesday that they saw little problem with replacing the genes of a stem cell to create an altered stem cell.
As long as researchers are not using human eggs to create and destroy human embryos, "there is no new pro-life issue here," said Richard Doerflinger, a spokesman for the U.S. Conference of Catholic Bishops. "It looks like you're just modifying an existing stem cell line."
If the Stanford scientists do attempt to make cloned human embryos, they would not be the first at a U.S. university. From 1999 to 2001, biologists at UC San Francisco made an apparently unsuccessful effort to create cloned human embryos in order to produce stem cells, the university said earlier this year.
Weissman said that "there's never been a meeting where we talked about" using cloning to produce stem cells.
The institute "will work first with mice to establish the best way to create stem cells," said Amy Adams, a university spokeswoman. "The preference is to transfer a nucleus into an established embryonic stem cell line. But that's the preference. If the best way to do this in mice is to use an actual egg, then that's what they will attempt to do in humans."