A
multinational team of researchers has shown for the first time
that the
immune system can stop the growth of a cancerous
tumour without actually killing it. Scientists have been
working for years to use the immune system to
eradicate cancers, a technique known as immunotherapy.
The new findings prove an alternate to this approach exists:
When the cancer can''t be killed with immune attacks, it may be
possible to find ways to use the immune system to contain it.
The results may also help explain why some tumours seem to
suddenly stop growing and go into a lasting period of
dormancy.
"Thanks
to the animal model we have developed, scientists can now
reproduce this condition of tumour dormancy in the laboratory
and look directly at cancer cells being held in check by the
immune system," said Robert Schreiber, Ph.D, Alumni
Professor of Pathology and Immunology, Washington University
School of Medicine, St Louis. "That will allow us to see
if we can model this state therapeutically," he added.
The
study''s authors call the cancer-immune system stalemate
equilibrium. During equilibrium, the immune system both
decreases the cancer''s drive to replicate and kills some of
the cancerous cells, but not quickly enough to eliminate or
shrink the tumour.
"We
may one day be able to use immunotherapy to artificially
induce equilibrium and convert cancer into a chronic but
controllable disease," suggests Mark J Smyth, Ph.D,
professor of the Cancer Immunology Programme, Peter McCallum
Cancer Centre, Melbourne, Australia.