Prozac Scientist Plays Down Cancer Fears
Prozac and related antidepressants could in theory pose a cancer threat by blocking the body`s innate ability to kill tumor cells, British scientists said on Tuesday.
Mar 26 3:26 PM ET
Al Musella's Comments: (This is his personal views and are not necessarily the views of the Musella Foundation!)
Posted on: 03/28/2002
Tue Mar 26, 3:26 PM ET
By Ben Hirschler, European Pharmaceuticals Correspondent
LONDON (Reuters) -
Prozac and related antidepressants could
in theory pose a cancer threat by blocking the body's innate
ability to kill tumor cells, British scientists said on
But Professor John Gordon of the University of Birmingham,
who led the research, said patients should keep taking their
drugs since there was no evidence of any link in practice.
Working in the test-tube, Gordon and others found that the
brain's mood-regulating chemical serotonin caused some cancer
cells to self-destruct.
Eli Lilly and Co.'s Prozac, Glaxo SmithKline Plc's Paxil
and Lundbeck's Celexa all "substantially blocked" this process.
The finding reopens controversy about the widespread use of the
class of antidepressants called selective serotonin re-uptake
inhibitors (SSRIs) that first went on sale in the 1980s.
Millions of people with depression and anxiety have been
prescribed the drugs, which have emerged as one of the biggest
sellers for the international pharmaceutical industry. They
work by stopping serotonin getting into cells.
Gordon's discovery (news - web sites) that serotonin plays a role in killing a
type of cancer called Burkitt's lymphoma was published in the
online edition of the medical journal Blood.
"We've shown that, in the test-tube, the SSRIs stop the
action of the serotonin on the cancer cells. But it's nigh on
impossible to extrapolate to what's happening in the body,"
Gordon told Reuters.
"We must stress the effects shown for SSRIs on cancer cells
is indirect and should cause no concern whatsoever to the many
millions of people throughout the world who are prescribed this
class of antidepressants."
A spokeswoman for Eli Lilly said the results of the study
were being misinterpreted to draw a link between SSRIs like
Prozac and an increased risk of cancer.
"The study really is based on test-tube results that didn't
involve human or animal subjects," said Anne Griffin of Lilly.
"There have been thousands of clinical studies of Prozac and
its use in some 40 million people, and there's been no link
A spokesman for Britain's Department of Health said the
research was at a very early stage and no increased risk of
cancer had been detected.
Rather than being alarmed, Gordon is in fact excited that a
new class of anti-cancer drugs may one day be developed that
exploit serotonin's ability to kill cancer cells.
"Because we know the mechanism, we are now in a position to
develop drug analogs of serotonin that will do the same job but
have better pharmacological properties," Gordon said.
His work also provides an intriguing insight into the way
that "positive thinking" associated with serotonin levels may
play a key part in effective cancer care.
The mechanism by which serotonin can get inside cancer
cells and tell them to commit suicide -- a process known as
apoptosis -- suggests there is a clear "dialogue" between the
brain and the immune system, he said.
Prozac was the first SSRI to reach the market in 1987 but
it has since been overtaken by Paxil, also known as Seroxat,
which racked up sales last year of 1.86 billion pounds ($2.7
Drug company officials said they did not believe their
pills caused any increase in cancer and questioned whether the
high doses used in Gordon's experiments may have affected the
"These data are from an in vitro (test tube) study and as
such they cannot be extrapolated to a clinical setting with any
degree of certainty," said Martin Sutton, a spokesman for GSK.
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