Marijuana Chemical Cannabidiol Halts Spread of Breast Cancer Tumors

A non-psychoactive chemical that occurs naturally in the marijuana plant may prevent breast cancer from spreading, according to a study published in the journalMolecular Cancer Therapeutics.

Researchers found that a chemical called cannabidiol (CBD) affects the activity of a gene known as Id-1 in patients with hormone-independent breast cancer. In embryos, Id-1 is responsible for helping cells grow and spread, but is supposed to remain inactive in adults. In human adults, it is found only in metastatic cancer cells, or cancer cells that are spreading throughout the body.

“When [the Id-1 genes] wake up, they are very bad,” said senior researcher Pierre Yves-Desprez. “They push the cells to behave like embryonic cells and grow. They go crazy, they proliferate, they migrate.”

According to Desprez, shutting off the activity of Id-1 can make cancer far less lethal. Tumors, Desprez says, can be “removed easily by surgery,” but if the cancer is spreading then the disease becomes much more difficult to contain.

“[Id-1 is like] an [orchestra] conductor,” Desprez said. “If you shoot the violinist, the orchestra just continues to play.”

“In this case, you shoot the conductor, and the whole orchestra is going to stop,” he said.

Because CBD occurs in only very small quantities in the cannabis plant, the researchers do not recommend smoking marijuana as a cancer treatment. To be effective, CBD will either have to be artificially synthesized or extracted and concentrated.

The chemical’s major advantage, according to the researchers, is its apparent non-toxicity.

“Right now we have a limited range of options in treating aggressive forms of cancer,” co-author Sean D. McAllister said. “Those treatments, such as chemotherapy, can be effective but they can also be extremely toxic and difficult for patients. This compound offers the hope of a non-toxic therapy that could achieve the same results without any of the painful side effects.”

The researchers also expressed hope that CBD will also prove effective against other cancers that rely on Id-1, including brain, colon and prostate cancer.