Cannabis 'increases cancer risk'
Smoking cannabis may suppress the immune system and increase cancer risk.
The drug triggers the production of cells that weaken the body's resistance to cancer, scientists believe.
A US study found that cannabinoids -- active compounds in cannabis -- activated biological pathways to generate "massive numbers" of MDSCs cells. MDSCs are immune cells that act as a safety brake on the immune system.
Cancer patients are known to have increased numbers of MDSCs. They suppress immune responses to prevent them getting out of control, but in so doing are also thought to promote cancer growth.
However, this might be helpful in suppressing the harmful immune reactions that lead to auto-immune diseases. A cannabis derivative has been shown to relieve symptoms of multiple sclerosis and rheumatoid arthritis.