Genetic
Profiling Predicts Treatment Responses in Breast Cancer
According to a recent article published in The Lancet, genetic
profiling using microarray analysis may predict a breast cancer
patient's response to neoadjuvant Taxotere ® (docetaxel).
Breast cancer claims the lives of approximately 40,000 women
and is diagnosed in approximately 200,000 women annually in
the United States alone. Chemotherapy remains a mainstay in
therapeutic regimens offered to patients with breast cancer,
particularly those who have cancer that has spread from its
site of origin. There are several chemotherapy agents that
have demonstrated activity in the treatment of breast cancer
and research is continuous in an attempt to determine optimal
chemotherapy agents and regimens. However, different patients
tend to respond differently to the same therapeutic regimen,
implying differences in genetic profiles. Cancers contain
different genetic mutations and researchers are now realizing
that different genetic variables affect how a cancer will
respond to various therapies. As research involving genetics
and associated responses to treatment matures, standard practice
will undoubtedly become more individualized, enabling physicians
to provide specific treatment regimens matched with a patient's
genetic mutation(s) to ensure optimal outcomes.
Taxotere ® is one of the most active agents in the treatment
of breast cancer. However, some women are inherently resistant
to Taxotere ® and do not respond to treatment involving
this agent. Researchers from the Baylor College of Medicine
and the Methodist Hospital in Houston, Texas recently conducted
a clinical study in an attempt to distinguish genetic mutations
that make patients either susceptible or resistant to the
anti-cancer effects of Taxotere ®. This study involved
24 patients with operable breast cancer. Biopsies (samples
of cancer cells) were obtained from each patient prior to
therapy with Taxotere ®. The cancer cells were processed
in the laboratory to determine differences in the levels of
expressions of genes, and these differences were compared
to a patient's response to treatment. Overall, the researchers
identified 92 genes that were indicative of response or resistance
to treatment with Taxotere ®. Accuracy of these 92 genes
in determining a response or resistance to Taxotere ® was
92% and 83%, respectively.
The researchers concluded that genetic profiling may provide
great accuracy in determining which patients would benefit
from a specific treatment and which patients would be receiving
unnecessary treatment with a specific agent. Specifically,
the 92-gene predictor model discovered in this trial may be
used to determine a patient's response to Taxotere ®, providing
a platform from which to begin individualized treatments.
However, the authors state that these results are preliminary
and need confirmation. Researchers affiliated with the National
Cancer Institute have initiated a large clinical trial to
further evaluate molecular profiling in patients with breast
cancer utilizing several different chemotherapy agents. Patients
with breast cancer may wish to speak with their physician
about the risks and benefits of participating in a clinical
trial further evaluating genetic profiling or novel therapeutic
approaches. Two sources of information regarding ongoing clinical
trials include the National Cancer Institute ( cancer.gov)
and www.cancerconsultants.com. Personalized clinical trial
searches on behalf of patients are also performed at cancerconsultants.com.
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