Cannabis Compound May Stop Metastatic Breast Cancer

Mar. 23 -- MONDAY, Nov. 19 (HealthDay News) -- A non-toxic, non-psychoactive compound in marijuana may block the progress of metastatic breast cancer, according to a new study by researchers in California.

"This is a new way to treat a patient that is not toxic like chemotherapy or radiotherapy. It is a new approach for metastatic cancer," said lead researcher Sean D. McAllister, an associate scientist at the California Pacific Medical Center Research Institute in San Francisco.

The compound found in cannabis, called cannabidiol (CBD), inhibits a gene, Id-1, that researchers believe is responsible for the metastatic process that spreads cells from the original tumor throughout the body.

Opting for a musical metaphor, senior researcher Pierre-Yves Desprez likened Id-1 to "an [orchestra] conductor. In this case, you shoot the conductor, and the whole orchestra is going to stop. If you shoot the violinist, the orchestra just continues to play."

In humans, the Id-1 gene is found only in metastatic cancer cells, said Desprez, a staff scientist at the institute. Before birth, they are present and involved in the development of human embryos, but after birth, they go silent -- and should stay that way, he said.

But in metastatic cancer "when [the genes] wake up, they are very bad," he said. "They push the cells to behave like embryonic cells and grow. They go crazy, they proliferate, they migrate." Desprez said, "We need to be able to turn them off."

According to the study, CBD does exactly that.

"We are focusing on the latest stages of cancer," Desprez added. The cancer cell itself is not the problem, because a tumor can be "removed easily by surgery," he said. The problem is the development of metastatic cells which is "conducted" by Id-1.

McAllister and Desprez said they are not suggesting that patients with hormone-independent metastatic breast cancer smoke marijuana. For one thing, a sufficient amount of CBD could never be obtained in that way, they said.