Chemo leaves behind cancer April 30, 2008 07:24am
WHILE chemotherapy can remove breast cancer tumours, it fails to root
out the stem cells that can revive the cancer, researchers said in a
study published in the US today.
Comparing the challenge to eradicating stubborn weeds from a garden,
the researchers at Baylor College of Medicine (BCM) in Houston,
Texas, said chemotherapy often fails because it leaves behind many of
the stem cells that help reignite tumours.
"It's not enough to kill the dandelion blossom and stalk that appear
above ground," said Michael Lewis, assistant professor of molecular
and cellular biology at the BCM Breast Cancer Centre. "You have to
kill the root beneath the soil as well."
The discovery underscores the need to develop a treatment that can
target stem cells in addition to the tumour, Prof Lewis said.
"What we found is that one reason chemotherapy frequently does not
work is that you kill the bulk of the tumour but leave many of the
stem cells behind," he said.
"It appears that these cells, by their nature, are resistant to the
effects of anti-cancer drugs," said Prof Lewis, whose findings appear
online in the Journal of the National Cancer Institute.
A cocktail of anti-cancer medicines together with the drug lapatinib
appears to kill both the tumour and the stem cells, he said.
The promising drug, still being evaluated, would be used to treat
breast cancer that has metastasised and contains the protein marker
called HER2.
The Baylor researchers took biopsies from the tumours of patients
with and without the HER2 marker before and after different
treatments.
In the group of people whose tumours did not carry the HER2 marker,
the 31 patients received conventional chemotherapy. While the number
of tumours significantly decreased, the proportion of cancer stem
cells was greater than before the treatment, the study said.
The other group - 21 patients with HER2 - were given lapatinib and
two common breast cancer drugs. That group saw a dramatic drop in
tumour cells, and the percentage of cancer stem cells remained
unchanged or even dropped slightly, the researchers said.
"The tumour shrank dramatically,
professor of medicine and medical director of the BCM Breast Care
Cancer Centre.
"But in contrast to treatment with conventional chemotherapy, the
relative proportion of stem cells did not go up. This means the stem
cells were killed off with the same frequency as the bulk of the
tumour. This is the first time this has been demonstrated.
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StemCells subscribers may also be interested in these sites:
Children's Neurobiological Solutions
http://www.CNSfoundation.org/
Cord Blood Registry
http://www.CordBlood.com/at.cgi?a=150123
The CNS Healing Group
http://groups.yahoo.com/group/CNS_Healing
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