“Studies show that cancer cell invasion or metastasis is the primary cause of death in malignancies including breast cancer.

The existence of cancer stem cells (CSCs) in breast cancer may account for tumor initiation, progression, and metastasis.

Recent studies have reported different effects of cannabinoids on cancer cells via CB1 and CB2 cannabinoid receptors.

In the present study, the effects of ACEA (a selective CB1 receptor agonist) and AM251 (a selective CB1 antagonist) on CSCs and their parental cells were investigated.

It was observed that ACEA decreased CD44⁺/CD24^-/low/ESA⁺ cancer stem cell invasiveness.

Since one of the main cancer recurrence factors is anti-cancer drugs fail to inhibit CSC population, this observation would be useful for cancer treatment.”

https://www.ncbi.nlm.nih.gov/pubmed/29552056

“Our results indicate that cannabinoids may interfere with invasive cancer stem cells in benefit of cancer eradication. In summary, our results clarified that cannabinoid receptor agonist possesses anti-invasion potential in both main population and breast cancer stem cells. Considering that most anti-cancer drugs do not eradicate stem cells and only target main population cells, the results disclosed here can be used for prevention of cancer recurrence.” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5843309/