Genome Scans May Reveal Life-Saving Alternatives for
TUESDAY, April 19 (HealthDay News) -- A 39-year-old woman is
referred to Washington University's Siteman Cancer Center in St.
Louis with suspected acute myeloid leukemia (AML), a cancer that
can be treated relatively simply with medication, or not so simply
with a high-risk stem cell transplant, depending on the tumor
But finding out which type of cancer she has proves trickier
While the pathologist sees a type of leukemia known as M3AML,
which generally has a good outcome and can be treated with the drug
ATRA, the cytogeneticist sees something entirely different. In his
analysis, the woman has a type of leukemia with poor long-term
survival that is usually treated with stem cell transplantation --
a risky therapy that sometimes leads to death.
Fortunately, in this case study, documented in the April 20
issue of the
Journal of the American Medical Association, the woman's oncologist is aware of a clinical trial and, deferring treatment for six weeks, refers her there so the researchers can do a full scan of her genome -- and come up with an answer.
Full-genome sequencing involves scanning all the thousand of
genes on the human genome to try to find a mistake. It's different
from the more common gene testing these days, which looks only for
specific DNA that might or might not be responsible for a
In the St. Louis case, the more in-depth sequencing, done in
only seven weeks, uncovered a new genetic "mistake" that showed the
could be treated with ATRA and not the more-complicated,
risky stem cell transplantation.
"A small portion of chromosome 15 had popped into chromosome 17," explained Richard K. Wilson, co-author of two case studies on full-genome sequencing in the journal.
The woman in this case study is now in remission and researchers
have actually used the new information to assess other atypical
cases of the leukemia, added Wilson, who is director of The Genome
Institute at the Washington University School of Medicine in St
In a second case, also documented in the journal, the outcome
was not so good for the patient, who died after battling several
different forms of cancer. But it did provide hope for her
children, who may have inherited her genes, and for other people
with the same syndrome.
This woman, 37 years old when she was first diagnosed with
breast cancer, had what's known as "cancer susceptibility
syndrome," in which people of a relatively young age without an
apparent family history of cancer develop multiple different types
of the disease.
While the woman had breast and ovarian cancer first, the last
cancer she developed was AML, which this group has been
Although the woman died at the age of 42, a full-genome scan did
reveal some useful information.
"We were expecting to find some interesting mutations in the tumor but we actually found the mutations in the germ line -- the normal cell DNA," Wilson explained.
This meant that "this was a mutation that happened very early in
her life that presumably resulted in a high susceptibility to these
cancers," he said.
The mutation was in the TP53 gene, which is involved in tumor
"The finding came too late to help her case but, we thought, if we're reading this correctly and if she has passed this gene along to her children, that would be very useful information for the family," Wilson said.
They went back to her physicians with the information who then,
assumedly, shared it with the family.
So when are other patients going to have access to this type of
sophisticated and sometimes life-saving scan?
Wilson guesses in about five-to-10 years.
One issue is cost, though Wilson is less worried about that one.
The scans for the two patients in the journal studies cost about
$40,000 to $50,000. They were free to the patients as part of the
study, but that's not the case for most Americans.
However, the price tag for genomic scans is falling. Wilson
noted that a year and a half ago, the cost was closer to $500,000
or $700,000. "Ask me next year, and it's going to be $10,000," he
A bigger challenge is having the skilled labor -- oncology
experts, cancer biology experts, geneticists, the patients' own
physician -- to do this. But Wilson is optimistic about that,
The case studies are also significant for "the speed at which
they were able to turn around the information, both on the
germ-line mutations [passed down between generations] and the
tumor-tissue mutations," noted Dr. Steven K. Libutti, director of
the Montefiore Einstein Center for Cancer Care in New York City.
"We've known how to sequence for decades. The major barriers were
cost and speed. They couldn't really sequence the entire genome in
a reasonable amount of time and expense to make it practical. Now
they've showed that advances have been made which can be applied to
For more on the latest genetics research and discoveries, head
Human Genome Project.
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