Further study is needed before CBD can be conclusively identified as a treatment option, McAllister and Desprez said. "We need to involve a team of physicians, because we are bench [basic] scientists," McAllister said.
One expert called the findings intriguing but preliminary.
"This is the first evidence that a cannabinoid can target the expression of an important breast cancer metastasis gene," noted Manuel Guzman, a Spanish expert on cannabinoids and cancer. He described the California study as giving "preliminary insight into the question of whether CBD could be used clinically to treat metastatic breast cancer."
However, "all the experiments in the paper have been conducted in cultured cells and none of them in any animal model of breast cancer, which would be one of the steps for further research," added Guzman, who is a professor of biochemistry and molecular biology at Complutense University in Madrid.
Guzman also noted that "Id-1 is just one of many genes involved in breast cancer metastasis" and that future research also needs to examine the impact of CBD on these other metastasis genes.
There's more on breast cancer at the U.S. National Cancer Institute.
SOURCES: Sean D. McAllister, Ph.D., associate scientist, California Pacific Medical Center Research Institute, San Francisco; Pierre-Yves Desprez, Ph.D., staff scientist, California Pacific Medical Center Research Institute, San Francisco; Manuel Guzman, Ph.D., professor, biochemistry and molecular biology, Complutense University, Madrid, Spain; November 2007, Molecular Cancer Therapeutics