Breast cancer (BC) is the most common cancer in women worldwide. Approximately 70-80% of BCs express estrogen receptors (ER), which predict the response to endocrine therapy (ET), and are therefore hormone receptor-positive (HR+). Endogenous cannabinoids together with cannabinoid receptor 1 and 2 (CB1, CB2) constitute the basis of the endocannabinoid system. Interactions of cannabinoids with hypothalamic-pituitary-gonadal axis hormones are well documented, and two studies found a positive correlation between peak plasma endogenous cannabinoid anandamide with peak plasma 17β-estradiol, luteinizing hormone and follicle-stimulating hormone levels at ovulation in healthy premenopausal women (original abstract available at


Cancers (Basel). 2020 Feb 25;12(3). pii: E525. doi: 10.3390/cancers12030525.
Cannabinoids and Hormone Receptor-Positive Breast Cancer Treatment.
Dobovišek L, Krstanović F, Borštnar S, Debeljak N.