Genetic
Signature Shows Risk for Cancer Recurrence
A
genetic "signature" that
consists of 186 genes combined together can predict the risk of recurrence
for some common
cancers, according to a report in the New England
Journal of Medicine (NEJM).
A set of genes predicts the recurrence of breast
cancer, prostate cancer, lung cancer, and medulloblastoma, the most
common form of childhood brain cancer, the researchers found.
"This is very impressive data that will hopefully
be able to predict which patients can benefit or not benefit from certain
types of treatment," says Dr. Jay Brooks, at Ochsner Health System
in Baton Rouge. "Whether this can be taken into the direct clinical
arena will remain to be seen."
The authors of the study, from Stanford University
and the University of Michigan, say they are already working to make
the findings available to physicians and their patients.
A
small number of cells within breast cancer are believed to be the
ones
that actually cause the cancer to grow. These "cancer
stem cells" were first identified in 2003.
The
researchers participating in the new study compared the gene expression
profile
of breast cancer stem cells with that of
normal breast cells. From that data, the researchers culled a list
of 186 genes that comprised an "invasiveness" gene signature.
This signature was then evaluated to see how it
related to overall survival as well as metastasis-free (no cancer spread)
survival in patients.
As it turned out, there was a strong correlation
between the gene signature and both overall and metastasis-free survival,
note the researchers.
The
gene signature was then combined with prognostic criteria from the National Institutes of
Health (NIH) to classify patients into those with a "good" or "poor" prognosis.
Those with a good prognosis had a 10-year rate of
metastasis-free survival of 81 percent, while those with a poor prognosis
had a rate of 57 percent.
And when the gene signature was combined with a
second group of genes previously identified by researchers, the signature's
predictive value was even more accurate.
A second study reported in the same issue of the Journal found
that denser breasts were associated with a higher risk of breast cancer.
The risk was elevated in cancers found both at screenings
and in the period between screenings, according to Dr. Norman Boyd,
at Princess Margaret Hospital in Toronto.
Women with breast density in 75 percent or more
of their baseline mammogram had about a five times greater risk of
breast cancer, compared with women who only had density in 10 percent
of their first-ever mammogram.
The findings held true after adjusting for all known
risk factors for the disease.
These findings confirm previous research, but they
use more modern technology, says Dr. Boyd.
"We wanted to see whether we would see similar messages
with modern mammography, and we did," he says. "We also wanted long-term
observation.
"Women should understand that this [breast density]
is indeed a risk factor with the same kind of awareness they might
accept knowing that some of their relatives have breast cancer," notes
Dr. Boyd.
"If they know they have dense breast [tissue] and
something changes, they may report it more promptly," he says.
And women on hormone replacement therapy, which
can increase breast density, should talk with their physician about
what they should do, explains Dr. Boyd.
Always consult your physician for more information.
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