Scientists announced Sunday that they have
finished mapping virtually all of the genetic mutations in breast
cancer, an effort that could soon change the way patients are treated
and eventually help researchers develop better treatments.
catalogue of human breast cancers is nearly complete," says study
co-leader Matthew Ellis of the Washington University School of Medicine
in St. Louis. "It's the breast-cancer equivalent of putting a man or
woman on the moon."
Among the most striking
findings: One of the most lethal types of breast cancer is genetically
closer to a kind of ovarian cancer than it is to other breast tumors,
according to the paper, published online today in Nature.
discovery could soon produce real benefits for breast cancer patients,
Ellis says. Women with so-called basal-like breast tumors -- also known
as triple-negative cancers -- would likely do better on a much less
toxic chemotherapy regimen, which is currently the standard of care in
Such shifts show that doctors
are beginning to change the way they look at cancers, focusing less on a
tumor's organ of origin and more on the inner workings of its nucleus,
down to the molecular level, Ellis says.
because it's a breast cancer doesn't mean it's like every other breast
cancer," says Brad Ozenberger, who oversees the research project, called
The Cancer Genome Atlas, at the National Institutes of Health.
ambitious federally funded program -- with a budget of $100 million a
year -- aims to be the cancer equivalent of the Human Genome Project,
which decoded and mapped the human genetic blueprint. Scientists already
have published the genomes of four other cancers: brain, ovarian,
colorectal and lung. In this study, scientists analyzed tissue from 348
breast cancers, finding that most tumors are caused by mutations in 30
to 50 genes, Ellis says.
The genome atlas
could give drug companies ideas for new drugs that target key genetic
mutations in cancer, Ozenberger says. In addition, the catalogue of
genetic mistakes can also help scientists better understand how cancers
develop and spread, Ozenberger says.
example, they may discover that a newly discovered gene is involved in
the immune system -- providing a clue to how cancer eludes the body's
normal defenses. Already, the program has given researchers clues that
both ovarian and triple-negative breast tumors could be vulnerable to
drugs that block new blood vessel growth, which aim to starve tumors.
tumors account for about 10% to 15% of all breast cancers, and are more
common among younger women and African Americans. Today, women with
triple-negative tumors are treated like many other breast cancer
patients, getting drugs called anthracyclines that can damage the heart
and cause leukemia or a type of "pre-leukemia," called myelodysplastic
syndrome, or MDS. Ellis' recent research, however, suggests
anthracyclines don't help women with triple-negative tumors.
Robin Roberts, host of Good Morning America,
underwent a bone-marrow transplant Thursday for MDS, caused by her
successful treatment for triple-negative breast cancer in 2007. Another
insight from the study: Doctors should reconsider an experimental class
of drug called PARP inhibitors for triple-negative breast cancer,
because early trials in ovarian cancer have been promising, Ellis says.
cancer survivor Roxanne Martinez says she "choked up" when she heard
that future patients might be able to skip the most toxic
chemotherapies. Martinez, 32, was treated for triple-negative disease
two years ago, while she was pregnant with her daughter.
both she and her daughter are currently healthy, Martinez says
anthracycline drugs made her very sick. Now, she worries about her
long-term health. Martinez, of Forth Worth, says she's fascinated by the
similarities between breast and ovarian cancers, which run in her
family. Doctors have long known of links between breast and ovarian
One of the best known breast cancer
genes, BRCA1, dramatically increases the risk both of ovarian cancer and
triple-negative breast tumors. Martinez says she's thrilled that women
with triple-negative tumors -- who today have the fewest treatment
options -- could have better care due to this study. "Just the idea of a
targeted treatment plan, that gives me so much hope," Martinez says.