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Proof That Cannabis Needs To Be Part of Treatment For Breast Cancer

Soumya Nalam
Cancer Patient Woman in Bed

These studies tell us that cannabinoids are effective in reducing tumor growth, size, and stopping metastasis in breast cancer cells.

Breast cancer is the most common, and is now the second leading cause of cancer death in American women (lung cancer is number one). Metastasis is the big killer, responsible for approximately 90% of breast cancer-related deaths.  This disease requires treatment using additional alternative therapies that have increased efficacy and low toxicity.

Studies suggest that regulation issues within the endocannabinoid system may trigger cancer by fostering the body conditions that allow mutated cells to proliferate and migrate. Cannabinoid receptors CB1 (central) and CB2 (peripheral) have been shown to be over-expressed in tumor cells (compared with normal cells) for various types of cancers, especially breast and liver cancers.

Black and white image of woman covering each breast with her hands

Synthetic Cannabinoids and Breast Cancer Cells

Given that breast cancer tumors have more CB2 receptors than healthy tissue does, a team of researchers set out to find out if cannabinioids could be used to stop the tumor growth. The study used a synthetic CB2 agonist (a chemical that binds to the receptor and activates it). THC, found in the cannabis plant, is natural agonist of the CB2 (and CB1) receptors.

Mice treated with the synthetic CB2 agonist saw 40-50% reduction in tumor growth and 65-80% reduction in metastasis. Additionally, when scientists treated the cancerous mice with a CB2 antagonist (a chemical that prevents receptor activation), these benefits reversed. This tells us that endocannabinoid receptors modulate tumor growth and metastasis.

Close up woman rolling a joint for breast cancer

Patients (91%) with the HER-2 mutation (ErbB2-positive tumors) over express CB2 receptors. HER-2 is a very aggressive form of breast cancer, compared to other forms.  Fortunately, both THC (phytocannabinoid) and the synthetic CB2 agonist reduced tumor growth, tumor number, and the amount/severity of metastases in animal models of HER-2.

Cannabinoids also have a modulatory effect on triple negative breast cancer cells (cancer cells that lack HER-2/ErbB2, estrogen and/or progesterone receptors).

Interestingly, COX-2 is an inflammatory enzyme that expresses in 40% of human cases for invasive breast cancer.  This enzyme promotes metastasis. Studies have shown that a cannabinoid called cannabidiolic acid (CBDa) is a selective COX-2 inhibitor. This means that CBDa inhibits COX-2 by down-regulating and also through the suppression of genes that are positively involved in the metastasis of cancer cells.

Cannabinoids exert their anti-cancer effects by binding to CB1 and CB2 receptors. Since these anti-tumorigenic effects are dependent on the cell line or tumor type, the endocannabinoid system provides a targeted treatment of cancer by demonstrating selective action on tumor cells while not affecting normal cells.

Stathmin and Tau Protein Regulation

Microtubule Associated Proteins (MAPs) stathmin and tau are the key proteins in cancer metastasis. Both interact with microtubules (responsible for forming cytoplasm, the living matter of all cells) to regulate their function.

People use stathmin, a phosphoprotein, to measure and predict the aggressiveness of many cancers. These include endometrial and breast cancers. High stathmin levels in a primary tumor is an identifier of high risk for recurrent disease in patients. Unfortunately, it also predicts a poor overall survival rate; and it predicts a less robust response to chemotherapy. When doctors measured stathmin and tau expression levels in breast cancer cells, the analysis showed that the ratio of a high tau to stathmin ratio is prognostic for improved survival in breast cancer patients.

cannabis plant for breast cancer

A Cannabis sativa extract effectively reduced tau and stathmin gene expression in cancer cells. It also significantly decreased the migration of cancer cell lines. Growing evidence indicates that tau can provide a selective advantage during metastasis in cancer patients. Since this protein contributes to the metastatic efficiency of breast tumor cells, anti-tau drugs may potentially inhibit tumor metastasis.

This indicates that cannabis-based medicines are effective supplemental treatment in cancer patients.

Soumya Nalam

An expert content strategist with over a decade's experience. A double gold medalist with a Master's in Life Sciences (Biochemistry & Molecular Biology). Editor-in-charge at CureJoy, Senior Publishing Specialist and Reuters and Optimization Specialist at Google AdSense.

  • Avatar

    Does CBD oil purchased in Canada Cannabis stores the same as whats described here ??

    August 14, 2019 at 6:39 pm Reply
    • Jennifer Grant

      Hi Paul – the short answer is no, but the truth is longer. Let me try to explain. These studies are on synthetic cannabinoids = CB2 synthetic agonist JWH-133 and the CB1 and CB2 agonist WIN-55. That being said, THC is also an agonist for CB1 and CB2 receptors. Breast cancer has an over-expression of CB2 receptors and the presence of cannabinoids slow tumor growth in lab and in animal models. In Canada we have full spectrum cannabis oil that is sold by the LPs. This will have THC and CBD in different ratios. Studies are not complete on humans using cannabinoids from cannabis…but the results of this study suggest that (1) the endocannabinoid system is definitely involved in modulating tumor growth and metastasis and (2) CB2 receptor activation slows this growth and CBD is known to stop metastasis.

      August 14, 2019 at 10:12 pm Reply
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    Steve Andrews

    Iodine was taken out of baked goods back around 1980. It was in all baked goods. Iodine is very anticancer, inducing healthy, normal apoptosis of cells. Breast tissue has a very high affinity and need for iodine, second only to the thyroid. Breast cancer rates before 1980 were 1 in 20 women – today, it’s 1 in 7 women are predicted to get breast cancer in their lifetime. The key and cause is iodine deficiency, IMO. Why the breast cancer societies aren’t shouting this from the rooftops – we all know. They are money hungry and self serving.

    December 26, 2019 at 10:11 pm Reply

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