Health News
2006-03-31
Protein linked to
spread of breast, prostate cancer identified
Scientists have
identified and blocked the action of a protein linked to
the spread of breast, prostate, and skin c
Scientists have
identified and blocked the action of a protein linked to
the spread of breast, prostate, and skin cancer cells to the
bones. The molecule, called RANKL, is produced in bone
marrow. In studies of mice, researchers from Austria
and Canada showed that inhibiting the protein could
stop the cancerous cells from migrating to the bones.
"RANKL is a
protein which tells tumor cells to come to it," said
professor Josef Penninger of the Austrian Academy of
Sciences in Vienna. "It sits on the bones, and when
tumor cells circulate in the body, then RANKL attracts
them into the bones.”
Once a cancer has
spread beyond its original site in a process known as
metastasis, it becomes much more serious and difficult to
treat. An estimated 70% of patients with progressive
breast cancer and 84% of advanced prostate cancer
sufferers develop bone metastases.
The findings,
reported in the journal Nature, explain the
puzzle of why certain cancers spread to the bones and how
interfering with the process could help to prevent the
spread of the disease.
When the
researchers gave mice with skin cancer a drug that blocked
RANKL, the rodents had fewer tumors in their bones than
animals who were not treated. But the drug did not
slow the spread of the cancer to other sites in the
body.
Penninger and his
colleagues stressed that although the research was
done in mice, drugs that interfere with RANKL are in
development and could be used to test their findings
and show if the same holds true for humans. "This is
an idea that can be directly tested," Penninger added.
Nearly all breast
cancer tumors in women have the receptor for RANKL,
which Penninger said is an indirect indication that the
findings are relevant to humans.
"Since there are
novel inhibitors of RANKL far along in clinical
development, the idea is that people who have cancer that is
known to spread to bone can start taking this drug
when they are diagnosed," said D. Holstead Jones of
the University of Toronto, the lead author of the
study. "It would inhibit how much bone metastases they would
have.”
Every year an
estimated 1 million people develop metastases to the bones,
particularly women with breast cancer. Drugs that inhibit
RANKL may also help to alleviate the severe pain that
metastases can trigger and improve the quality of life
of patients.
Breast and
prostate are among the most common cancers. More than a
million new breast cancer cases occur worldwide each year,
and half a million men are diagnosed with prostate
cancer, according to the International Agency for
Research on Cancer in Lyon, France. (Reuters)
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