The new findings are published in the November issue of Molecular Cancer Therapeutics.
If McAllister's and Desprez's work results in the development of a cancer treatment, someone with metastatic cancer might be placed on CBD for several years. That means low toxicity is important, McAllister explained.
McAllister also suggested that Id-1 is "so important in providing the [metastatic] mechanism in these cells in so many types of cancers" that they "provide us an opportunity potentially to target other types of cancers."
The study's findings were "were a serendipitous discovery, in a way," McAllister said. Desprez noted that he had been working on the Id-1 gene for 12 years. His lab had demonstrated that it was a key gene for invasive breast cancer and tumor progression, and Desprez had found a way to inhibit it in mice, but not in humans.
Then, two years ago, McAllister -- an expert on cannabinoids -- and Desprez, a cancer researcher, started to work together. Through their combined forces "what we found is actually what I was looking for for the last 12 years," Desprez said.
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.
More information
There's more on breast cancer at the U.S. National Cancer Institute.
