In 1993, the 25,000-year-old mummy of a woman was discovered in Siberia. Analyses of the body revealed that this woman, dubbed the “Siberian Ice Maiden,” suffered from metastatic breast cancer. Among the artifacts found with her body was a small bag of cannabis. While it can’t be proven that she used cannabis to relieve her symptoms or cure her disease, the discovery points to the enduring link between marijuana and cancer—and scientists are now beginning to unravel just what that link may be.
Recent research in fields such as immunology (the study of the immune system) and epigenetics (the study of the switching mechanisms that suppress or express the coding of a given gene) is providing new insights about how cancer itself develops—and these studies reveal the complex ways in which cannabis compounds interact with the switching mechanisms of genes and cells to influence the development of tumors.
Until relatively recently, standard treatments for cancer focused on removing or destroying cancerous cells with a combination of surgery, radiation and/or chemotherapy. Within that model, cannabis has been shown to relieve the nausea, loss of appetite and other symptoms such as fatigue that are caused by those treatments.
Now, though, the newest cancer research focuses on finding new ways to deal with cancer by intervening in the processes that make it possible, rather than attacking cancerous tumors once they appear. This research reveals that cannabis may have the potential to attack cancer itself.
This cutting edge research by leaders in immunology and immunotherapy identifies checkpoints at which T-cells, the immune system’s frontline fighters against disease, either activate to stop malignancy—or don’t.
Therapies that target those checkpoints may be the most effective way to keep cancer cells from multiplying. New studies in epigenetics also explore the factors that can activate tumor suppression genes or keep defective genes, such as the breast cancer-related BRCA1 and BRAC2, in check.
Along with just about every other process in the body, the immune system is supported and moderated by the endocannabinoid system, an extensive network of cellular receptors that respond to cannabinoids for things like managing pain, calming anxiety and activating immune responses.
The body creates its own cannabinoids, but cannabinoids found in cannabis, such as tetrahydrocannabinol (THC) and cannabidiol (CBD), are so similar to the body’s own that they can affect any process that the endocannabinoid system manages. So these and potentially other compounds in the marijuana plant may be able to suppress the development of cancerous tumors.
So far, research has identified two endocannabinoid receptors, CB1 and CBD2, that can be activated by THC and CBD to trigger immune responses, cell growth and more. For those reasons, some studies indicate that these compounds may have surprisingly potent powers to act on the various checkpoints and switching mechanisms to cause the death of cancer cells and inhibit the growth and spread of tumors.
Gliomas are a family of stubborn, aggressive brain tumors that can be difficult to treat because they often spread among many areas of brain tissue, rather than concentrate into a single, solid tumor. In over two decades of studies, researchers from around the world found that THC can induce apoptosis, or cell death, in animals for certain types of glioma cells while protecting normal cells.
In studies examining the effects of cannabinoids on cancers as diverse as breast cancer and colorectal cancer, THC and CBD have been shown to cause cancer cell death and promote immune responses that inhibit new cancer cell growth. These cannabis compounds operate on EC receptors themselves, and on other processes that are affected by them to reduce cancer cell proliferation and cause the death of existing cancer cells. These studies were conducted on animals and on human cells in a laboratory setting.
Although these and other studies indicate that cannabis compounds may play a powerful role in promoting immune responses that could lead to the death of cancer cells and prevent the development of new ones, the relationship of marijuana to cancer is more complex than it appears. According to some studies, cannabis appears to promote tumor growth, not stop it. In others, high levels of THC may interfere with the development of blood vessels.
Efforts to come to a clear understanding of how cannabis alters cancer also depend on the kind of cannabis being studied and the nature of the study involved. While some studies use natural cannabis, others are based on FDA-sanctioned medications that contain CBD only. And some research is done on cell lines in a laboratory, while other studies are based on animal subjects or, in some cases, human trials.
These varying approaches make it difficult to determine what cannabis actually does about cancer. Regardless of these variables, though, more than two decades of research indicates that marijuana may exert a powerful influence on various points in the body’s progress toward developing cancer, and new studies are shedding light on the way those influences work. Cannabis is known to ease the symptoms of cancer treatment—but it may also be a potent weapon for stopping cancer in its tracks. As always, more research is required to study marijuana’s effect on the human population.
Photo credit: Paige Powers