Fun With Serotonin

Serotonin, a neurotransmitter that affects mood, appetite and
libido, has been shown to kill one type of cancer cell, fueling hope for
new drug therapies as well as concern that popular antidepressants
interfere with serotonin's cancer-fighting properties.

In test-tube experiments, scientists studied the effect of
serotonin on Burkitt's lymphoma, a cancer of the immune system. In high
concentrations, serotonin, which is found in the brain, gut and blood
platelets, entered cancer cells and caused them to self-destruct.

"If we can mimic serotonin's action, we might be able to halt
Burkitt's lymphoma," says Randy Blakely, Ph.D., director of Vanderbilt
University's Center for Molecular Neuroscience in Tennessee, and
co-author of the study, which appeared in the medical journal
Blood.

Scientists chose Burkitt's lymphoma because it has relatively few
survival genes, making it easier to trick the cells into
self-destructing, according to co-author John Gordon, Ph.D., a professor
of cellular immunology at the University of Birmingham in England.

The disease-fighting properties of serotonin suggest a possible
link between disposition and cancer, an illness some patients hope to
defeat with positive thinking. There is no empirical proof of the mind's
curative power, but "mood could effect the immune system and therefore
the development of cancer," maintains Gordon.

When Gordon and Blakely first reported their findings this spring,
one corollary sparked panic: Selective serotonin reuptake inhibitors
(SSRIs), the antidepressants of choice in contemporary pharmacotherapy,
prevent serotonin from entering Burkitt's lymphoma cells. The British
press widely misinterpreted this finding as evidence that the three SSRIs
studied, Prozac, Paxil and Celexa, may increase the risk of
cancer.

"Fifty million people worldwide take SSRIs," says Gordon. "There is
no evidence of any link between SSRIs and cancer."