CANNABIS MAY BLOCK GROWTH OF BRAIN CANCER

Cannabis chemicals may provide a new way of treating deadly brain
cancer.

Scientists have shown that cannabinoids, the chemicals responsible for
the drug's "high", deter the growth of blood vessels which feed the
tumour.

They appear to prevent genes making a protein called VEGF (vascular
endothelial growth factor) that stimulates the sprouting of blood vessels.

Cutting off tumours' blood supply is one of the latest anti-cancer
strategies being explored by scientists. In studies cannabinoids
significantly reduced the activity of VEGF in laboratory mice.

They also lowered VEGF levels in tumour tissue samples taken from two
patients with glioblastoma multiforme, the most lethal brain tumour
type.

About 4400 new cases of brain tumour are diagnosed in the UK each
year. A small percentage of these are grade four gliomas, the most
aggressive and dangerous brain tumours.

Only about 6% of people diagnosed with these high-grade cancers live
for more than three years. The disease is normally treated with
surgery, followed by radiotherapy and possibly chemotherapy. But the
main tumour often evades complete destruction and grows again to kill
the patient.

Cannabinoids had previously been shown to inhibit the growth of blood
vessels in mice. But the mechanism involved remained a mystery and it
was not known if the same effect occurred in humans.

In the new Spanish-led study, cannabinoids were injected into mice
with gliomas. DNA analysis was then carried out on 267 genes
associated with the growth of tumour blood vessels. It showed that the
cannabis compounds reduced the activity of several genes involved in
VEGF production.

Professor Manuel Guzman, from Complutense University in Madrid, said:
"In both patients, VEGF levels in tumour extracts were lower after
cannabinoid inoculation."