PHILADELPHIA The major active component of marijuana could enhance the ability of the virus that causes Kaposis sarcoma to infect cells and multiply, according to a team of researchers at Harvard Medical School. According to the researchers, low doses of -9 tetrahydrocannabinol (THC), equivalent to that in the bloodstream of an average marijuana smoker, could be enough to facilitate infection of skin cells and could even coax these cells into malignancy.

While most people are not at risk from Kaposis sarcoma herpes virus (KSHV), researchers say those with lowered immune systems, such as AIDS patients or transplant recipients, are more susceptible to developing the sarcoma as a result of infection. Their findings, reported in the August 1 issue of Cancer Research, a journal of the American Association for Cancer Research, offer cautionary evidence that those with weakened immune systems should speak with their doctors before using marijuana medicinally or recreationally.

These findings raise some serious questions about using marijuana, in any form, if you have a weakened immune system, said lead study author Jerome E. Groopman, M.D., professor of medicine at Harvard Medical School. While THC is best known as the main psychotropic part of marijuana, an analog of THC is the active ingredient of marinol, a drug frequently given to AIDS patients, among others, for increasing appetite and limiting chemotherapy-induced nausea and vomiting.

While previous studies indicated that marijuana smoking was associated with Kaposis sarcoma, this is the first to demonstrate that THC itself can assist the virus in entering endothelial cells, which comprise skin and related tissue.

According to Dr. Groopman, the study illustrates the complicated role marijuana and other cannabinoids play in human health. Numerous types of cells display cannabinoid receptors on their outer surfaces, which act as switches that control cellular processe
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Contact: Greg Lester
lester@aacr.org
267-646-0554
American Association for Cancer Research
1-Aug-2007