Antidepressants in the class called SSRIs (Prozac, Luvox, Paxil, Zoloft, Celexa, Lexapro) could potentially increase the risk for brain cancer, according to some researchers.
Professor John Gordon of Birmingham University found that SSRIs encouraged the growth of Burkitt's Lymphoma, a type of cancer which affects the lymphatic system, in test tube experiments. It is speculated that if they can affect the growth of this type of cancer they might also affect brain cancers in a similar way.
The mechanism of action for this increased risk is by blocking the body's natural ability to kill tumor cells. Gordon, whose results have been published online in the journal Blood, says that serotonin is a key player in stimulating apoptosis, a natural programmed cell death which brings into control runaway cell growth. Without this process to rein in these renegade cells, cancer may develop.
It is not known if these data can be extrapolated to mean that humans are at increased risk for developing cancer. Thus far, no SSRI-cancer link has been observed in clinical practice and drug company officials speculate that the high dose used in Gordon's experiment may not provide a reliable indicator of what happens in the patient.
The specific drugs investigated by Gordon were Prozac, Paxil and Celexa.Source: Adamantios Serafeim, Gillian Grafton, Anita Chamba, Christopher D. Gregory, Randy D. Blakely, Norman G. Bowery, Nicholas M. Barnes, and John Gordon. "5-Hydroxytryptamine drives apoptosis in biopsylike Burkitt lymphoma cells: reversal by selective serotonin reuptake inhibitors." Blood 2002 99: 2545-2553.