Research studies are showing that incorporating whole plant (full-spectrum) cannabinoids into a natural supplement regimen may reduce tumor aggression in HER2+ breast cancer.

Hormone-sensitive breast cancers are classified using two biomarkers: hormonal receptors (estrogen receptor and progesterone receptor) and the HER2 oncogene. In a patient’s diagnosis this is denoted as ER+, PR+ and HER2+, with any combination of biomarkers possible.

HER2+ breast cancer, which expresses the human epidermal growth factor receptor, is strongly influenced by the Endocannabinoid System (ECS), specifically the cannabinoid receptor CB2. Cannabinoid receptor expression is higher in tumor cells when compared to normal tissues, meaning that some endogenous/internal cannabinoids have cancer promoting potential. CB2 receptors were reported to be present in 72% of breast carcinomas, and 91% of these tumors were HER2+.

HER2 oncogenes promote the upregulation/increased CB2 activity by binding to the receptor and forming what is called a heterodimer (two similar molecules linked together). In reciprocation, the expressed CB2 receptors play a pivotal role in increasing HER2’s contribution to cancer activity. The molecules feed each other and are linked to poor treatment outcomes and lower patient survival rates.

When patients ingest full-spectrum cannabis, the THC phytocannabinoid molecule binds to CB2 receptors, breaking apart the CB2-HER2 heterodimer complex as well as other HER2 complexes.

This separation triggers a chain reaction of secondary messenger signaling, that results in a reduction of CB2 expression and HER2 cancer aggressiveness. In addition, THC’s anti-tumoral effects are enhanced when delivered in a whole plant cannabinoid oil, an average 15-25% stronger than just the single THC molecule.

Although I prefer patients seek individualized testing to determine which forms, brands, and dosages of cannabis are right for them, I am comfortable recommending that any HER2+ breast cancer patient consider incorporating some form of full-spectrum cannabinoid into daily supplement regimens.

Note: At this time, recreational cannabis is not legalized in Minnesota, so all THC-dominant cannabinoids must be purchased through a licensed medical professional.

For more information on Conners Clinic or to contact use, please visit or call our office at 651.739.1248.


  1. Andia, Alex. THC Versus Breast Cancer. Project CBD. [Online] March 18, 2019. [Cited: July 30, 2019.]
  2. Pérez-Gómez, Eduardo, et al. Role of Cannabinoid Receptor CB2 in HER2 Pro-oncogenic Signaling in Breast Cancer. Research Gate. [Online] Journal of National Cancer Institute, June 2015. [Cited: July 31, 2019.]
  3. Devitt-Lee, Adrian. Quick Hit: CB2 In Breast Cancer. Project CBD. [Online] March 18, 2019. [Cited: July 31, 2019.]
  4. Ladin, Daniel A, et al. Preclinical and Clinical Assessment of Cannabinoids as Anti-Cancer Agents. NCBI. [Online] October 7, 2016. [Cited: July 31, 2019.]