BANGKOK, Thailand -- Gene editing tools such as CRISPR are helping
researchers who hope to cure cancer and other problems involving DNA,
but "making embryos in a dish" is a much easier way to check for
mutations before implanting an embryo in a mother's uterus, according
to an American Cancer Society professor.

"Gene editing, or CRISPR, is enormously helpful for us at the research
level," said Mary-Clare King, American Cancer Society professor of
Genome Sciences and Medicine at Seattle's University of Washington.

"We work with CRISPR using cells in plates. We alter the cells and we
see what works, and what doesn't, by way of treating the cells that
we've altered. I think of it as a research tool," Ms. King said in an
interview on February 1.

"I don't think of it as a tool that will ever be deployed for actually
correcting these kinds of cells, because there are a lot of easier
ways to do it."

Ms. King was visiting Bangkok to receive Thailand's annual Prince
Mahidol Award along with three other recipients for their work in
medicine and public health.

She "discovered a gene causing breast cancer, the most common cancer
among women," the award foundation said.  "In 1991, Prof. King found a
gene called BRCA1, in which its mutation leads to breast cancer. It
was demonstrated for the first time that the diseases can be

Some scientists are currently experimenting with CRISPR to change DNA
in human embryos so newborns would be free of inherited diseases
passed on from generation to generation via mutations.

In China, a scientist is being investigated for claiming to have
edited the genes of babies to ensure they are safe from HIV.

Much easier than editing DNA with CRISPR "for breast cancer
predisposition and for far more serious diseases that can't be
prevented, is to couple genetic diagnosis -- that is the
identification of the exact DNA mutations that are responsible for a
trait -- with pre-gestational diagnosis," Ms. King said.

"This strategy involves taking mother's eggs and father's sperm from
the biological parents. No surrogates. No editing. No anything. Making
embryos in a dish. Testing the embryo at the eight-cell stage by
removing one cell, which is fine, the embryo just grows it back. And
then checking if that embryo is free of the mutations that are present
in one, or the other, or both of the parents.

"If that embryo is free of those mutations, we implant it in the
mother's uterus and she goes on and has a healthy child. That
strategy, coupled with genetic diagnosis, is enormously powerful. It
doesn't involve any CRISPR editing," she said.

"There is no danger there for any sort of untoward consequences,
because you're not doing anything to the cells except checking them.
You're not doing anything that alters the cells. You're simply being
sure that you have a healthy embryo.

"No abortion is involved. No termination is involved. No editing is
involved. So why the hell would anyone edit, when in fact you can do
this properly with modern technology to find out exactly what's wrong
and then make sure that the mother will be carrying an embryo that's
just right," Ms. King said.

National Public Radio reported on February 1 that developmental
biologist Dieter Egli at Columbia University in New York said he is
conducting human embryo experiments "for research purposes."

Mr. Egli said he wanted to determine whether CRISPR can safely repair
mutations in human embryos to prevent genetic diseases from being
passed down from earlier generations.

"So far, Egli has stopped any modified embryos from developing beyond
one day, so he can study them," NPR reported.

"Right now we are not trying to make babies. None of these cells will
go into the womb of a person," Mr. Egli said.

He was studying ways of preventing congenital illnesses such as
Tay-Sachs, cystic fibrosis, Huntington's disease
and inherited blindness.