Pubdate: Tue, 29 Feb 2000
Source: Daily Telegraph (UK)
Copyright: Telegraph Group Limited 2000
Author: David Derbyshire, Science Correspondent


Chemicals Found In Cannabis Can Destroy Life-threatening Brain
Tumours, A New Study Says Today.

Scientists have found that the main active ingredient in marijuana halts
the growth of malignant gliomas - deadly cancerous growths in the brain.
The discovery will add to the growing calls from patients and doctors to
legalise cannabis for medical use.

In the past few years, scientists have rediscovered the medicinal
properties of cannabis. Studies have shown that substances in the plant can
ease the symptoms of multiple sclerosis, prevent nausea and offset
side-effects of cancer chemotherapy. Now cannabis could also be used as an
anti-cancer drug, says a team from Complutense University in Madrid,
reporting in the journal Nature Medicine.

Researchers induced tumours in the brains of 45 rats. A third were given
THC, the main active chemical in cannabis, a third were given a synthetic
cannabinoid, while the rest were used as controls.

Within 18 days the untreated rats died but, when THC and the man-made
cannabinoid were injected directly in the tumours over seven days, they had
a dramatic effect. The chemicals destroyed the tumours in a third of the
mice and prolonged the life of another third by up to six weeks. "These
results may provide the basis for a new therapeutic approach for the
treatment of malignant gliomas," the team, led by Dr Manuel Guzman, report.

Dr Daniele Piomelli, pharmacologist at the University of California in
Irvine, said the discovery could have important implications for tumour
treatment. He said: "Although incomplete, these findings must be seriously
considered as glial tumours are peculiarly resistant to traditional therapy."

Spanish researchers believe that cannabinoids trigger the build-up of a
chemical messenger, ceramide, which in turn leads to programmed cell death
in the tumour. The chemicals were selective, only triggering cell death in
cancerous brain cells. Future studies will try to find out why the
cannabinoids appear to have no effect on healthy brains and whether they
can be used on people. Gliomas are extremely difficult to treat. Even after
a course of surgery, radiation and chemotherapy, the median survival rate
is less than a year. In Britain, there are 1,800 new cases a year.

In some American states, doctors can encourage the use of cannabis legally
to relieve nausea in cancer treatments, prevent weight loss in Aids
patients, ease spinal injury pain and slow the advance of the eye disease
glaucoma. Last year, American researchers showed that another chemical in
cannabis called anandamide could be used to treat Parkinson's disease and

The British Medical Association supports the use of cannabinoids in drugs
research but is against the legalisation of cannabis for medicine. Cannabis
plants contain more than 400 active ingredients, many of which have
unpredictable side-effects.
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