Marijuana use may be a driving factor in the rise of head and neck cancer cases, according to a new study. By The Fresh Toast's Kate-Madonna Hindes, provided exclusively to Benzinga Cannabis.
Daily Cannabis Use Can Drive HPV-Related Tumor Growth, Study Finds
Marijuana use may be a driving factor in the rise of head and neck cancer cases, according to a new study.
Published in Clinical Cancer Research, the research found that tetrahydrocannabinol (THC) can activate a molecular mechanism in the body that accelerates tumor growth in patients with human papillomavirus (HPV)-positive skin cancers.
The big (TH)C
To find their results, the research group from the University of California San Diego School of Medicine investigated how THC in the bloodstream affected the p38 MAPK pathway, a molecular mechanism that controls programmed cell death.
After injecting cannabinoids into animal cells, human cells, and mice, the researchers found that THC does activate p38 MAPK, which then inhibits cell death and allows any tumors to progress.
The team then checked the blood plasma levels of 32 people with head and neck squamous cell carcinoma (HNSCC). And like the cell lines, the blood samples showed p38 MAPK activation and loss of cell death in tumors from patients with THC in their blood.
“We now have convincing scientific evidence that daily marijuana use can drive tumor growth in HPV-related head and neck cancer,” Joseph A Califano III, the paper’s senior author, said in a statement.
HNSCC is the sixth most common cancer in the world, and approximately 30 percent of those living with the condition display an HPV infection. Coupled with lagging HPV vaccination rates, Califano and his colleagues are concerned that rising rates of cannabis use could boost the disease’s prevalence.
“HPV-related head and neck cancer is one of the fastest growing cancers in the United States,” he wrote in a press statement. “While at the same time, exposure to marijuana is accelerating. This is a huge public health problem.”
Cannabis and cancer
Previous studies have suggested that HPV status may be a modifier to any cannabis- HNSCC association. In a 2008 paper, researchers found an increased risk of head and neck cancer for cannabis-consuming HPV-16–positive patients, but found no association between the drug and the disease for HPV-16–negative patients.
Lung cancers, on the other hand, appear to have a null association with cannabis use, despite the presence of carcinogens in cannabis smoke. A popular explanation for this net inertia is that the tumor-suppressant effects of THC and other cannabinoids actually counteract any carcinogenic activity.
However, in the case of head and neck cancer in HPV-positive patients, these anti-tumor properties don’t appear to be having a benefit.
“Marijuana and other cannabis products are often considered benign,” Califano continued, “but it is important to note that all drugs that have benefits can also have drawbacks. This is a cautionary tale.”
Califano and his colleagues now suggest that THC’s cancer-fighting properties need additional critical evaluation.
“Past studies showing anticancer effects of THC and other cannabinoids often used levels of THC higher than those found with recreational use, but doses used recreationally clearly activate a cancer-causing pathway,” he added.
Speaking to Analytical Cannabis in September last year, cannabis-cancer researcher Dr David Meiri explained the importance of dosage when discussing cannabinoids’ anti-tumor properties. “When you have defect in [a] pathway, which sometimes happens in cancer, the cannabis can change things that will lead the cells to die,” he said.
“[But] the dosing is [also] very, very important,” he added. “You want to find the ratio that will kill the cancer, but not the normal cells. It’s a matter of ratio and the amounts, and what caused the cancer, and why it’s different from the normal.”
In their follow-up research, Califano and his team plan to test whether another famous cannabinoid, cannabidiol (CBD), affects cell growth in the same way as THC.
Science Writer & Editor
Leo joined Analytical Cannabis in 2019. From research to regulations and analysis to agriculture, his writing covers all the need-to-know news for the cannabis industry. He holds a bachelor’s degree in biology from Newcastle University and a master’s degree in science communication from the University of Edinburgh.
Like what you just read? You can find similar content on the topic tag shown below.
Stay connected with the latest news in cannabis extraction, science and testing
Get the latest news with the FREE weekly Analytical Cannabis newsletter
Marijuana And HPV: Friend Or Foe?
Often called the common cold of the sexual world, the Centers for Disease Control states that HPV has infected over 79 million individuals worldwide. Both prevalent and highly contagious, HPV tends to thrive on porous skin located in the throat, anal cavity, cervix and tongue, making it extremely difficult to test and eradicate around the world.
Risk factors of HPV are a compromised immune system, smoking and poor diet and sleep. Thought to cause over 70% of cervical cancers, the World Health Organization states that HPV has more than 100 types and has one of the best known defenses: vaccination.
For decades, researchers believed that marijuana played a role in HPV-related cervical cancer. However, a 2010 study, published in the U.S. National Library of Medicine, found that marijuana did not cause cervical cancer.
Understanding HPV’s infectivity
While once thought to only be contracted through sexual conduct, studies in the last two decades have showcased that HPV can live on surfaces. One study, published in the British Medical Journal in 2002 found HPV DNA could live in a clinical environment, without skin-to-skin contact. A more recent and in-depth study, featured in Taylor & Francis Online, found that when comparing the bovine papillomavirus with the human papillomavirus, both showed a remarkable ability to retain a 50% infectivity at room temperature after 3 days.
Additionally, in 2014, Penn State further researched on earlier findings, finding that unless a special method of cleaning instruments (autoclaving) or bleach was present, HPV was persistent on surfaces and was able to be transmitted. While still cited as a “sexually-transmitted infection,” HPV appears to be anything but.
Craig Meyers, a professor of microbiology and immunology at Penn State College of Medicine explained, “Chemical disinfectants used in the hospitals and other healthcare settings have absolutely no effect on killing human papillomavirus… unless bleach or autoclaving is used in the hospital setting, human papillomavirus is not being killed and there is a potential spread of HPV through hospital acquired or instrument or tool infection.”
Photo by Joe Raedle/Staff/Getty Images
THC’s Role with HPV
A recent study published by Joseph A. Califano III, MD, found an interesting juxtaposition between HPV and THC. He shared in a report to UC San Diego Health that he felt since HPV-related head and neck cancers along with marijuana use were both on the rise, there might be a correlation between the two. His father, Joseph A. Califano Jr., is the former Secretary of State and well-known founder and chairman to the National Center on Addiction and Substance Abuse (CASA) at Columbia University, who heads an organization speaking out against marijuana.
In the study, Califano III cited that THC turned on the p38 MAPK, (protein that respond to stress or other stimuli) and while the protein was signaled on, HPV-positive head and neck cancer lost apoptosis (a form of cell death.) Meaning, THC seemed to ignite the protein that allowed HPV to continue growing at an alarming rate. Citing the study as a, “cautionary tale,” Califano III is now heading a study to see if CBD has the same effect.
Interestingly, an earlier study directly opposite of Caifano’s findings was published in 2016 by North-West University in Potchefstroom, South Africa.
Citing the same method of apoptosis, researchers found that CBD could be considered anticarcinogenic for cervical cancer. The data further illustrated that, “cannabidiol rather than Cannabis sativa crude extracts prevent cell growth and induced cell death in cervical cancer cell lines.” Could cannabis hurt head and neck cancers while CBD kills cancer cells in the cervix?
Kellie Lease Stecher, MD, a gynecologist in Edina, a suburb of Minneapolis, Minn. believes both studies highlight the importance of ongoing research. “While marijuana use is climbing due to legality, more studies must be done to look at the HPV’s DNA and how each strand is effected by CBD or marijuana,” Stecher explained. “Further studies should examine how HPV expression is altered by marijuana or its components in different tissues; as we don’t have enough data to determine if CBD or THC is helpful or harmful due to conflicting data.”
With an eye to the future and ever-climbing HPV-positive cancer rates, research can’t come soon enough.
Featured image by Getty Images
Original publication: 2020
© 2022 Benzinga.com. Benzinga does not provide investment advice. All rights reserved.