The possible link between marijuana and cancer

The negative effects of marijuana on teenagers' brain development have come into sharper focus lately; now, a study in the European Journal of Immunology shows how cannabis can adversely affect the immune system. Dr. Prakash Nagarkatti of the University of South Carolina led a team of immunologists who found that marijuana consumption can leave the body open to a host of serious diseases, including cancer. Here's a brief guide to Dr. Nagarkatti's findings:

What's the central conclusion?

Nagarkatti found that chemicals in cannabis, including its psychoactive ingredient THC, may lead to an increasingly vulnerable immune system. His team found that marijuana activates a group called myeloid-derived suppressor cells, or MDSCs. These cells often act as a "safety brake" on the immune system by ensuring that it does not go too far in fighting a disease. But in the case of cancer patients, MDSCs over-multiply, leaving the immune system weakened. Marijuana consumption mimics this response, Nagarkatti discovered, leaving the body more open to pneumonia, cancerous tumors, and bacterial infections like Legionnaire's disease.

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Is this all bad news?

Not necessarily. Even though a surplus of MDSCs can lead to infections, says Nagarkatti, "further research of these compounds could provide opportunities to treat a large number of clinical disorders where suppressing the immune response is actually beneficial."

Is this a definitive link?

It has not yet been established definitively, since it is unclear whether trials on mice will translate into human results. Says Henry Scowcroft of Cancer Research UK: "The issue of whether cannabis can cause cancer is a controversial one that is still not settled."

Sources: The Daily Mail, eMaxHealth