New research suggests tetrahydrocannabinol, or THC -- the main psychoactive ingredient in marijuana -- works to slow tumor growth.
Previous studies have demonstrated such effects in lab experiments involving mice with brain tumors, but researchers say the newest research isolates the tumor-shrinking mechanism. The latest study involved mice featuring tumors grown from human breast cancer cells.
When tumors were exposed to THC they once again shrank and eventually died. But researchers were able to discern where the anti-cancer action was happening, the CB2 and GPR55 receptors.
"By identifying the receptors involved we have provided an important step towards the future development of therapeutics that can take advantage of the interactions we have discovered to reduce tumor growth," said Peter McCormick, a researcher at the University of East Anglia's School of Pharmacy and author of the new study, published this week in the Journal of Biological Chemistry.
McCormick says these revelations don't mean cancer patients should start smoking pot.
"Our research uses an isolated chemical compound and using the correct concentration is vital," McCormick added. "Cancer patients should not use cannabis to self-medicate, but I hope that our research will lead to a safe synthetic equivalent being available in the future."
The federal government still classifies marijuana as a dangerous drug -- on par with heroin and LSD -- with "no currently accepted medical use."