Researchers at the University of California, San Diego School of Medicine have identified the molecular mechanism activated by the presence of THC that accelerates cancer growth in patients with human papillomavirus (HPV)-positive head and neck squamous cell carcinoma.
Head and neck squamous cell carcinoma is the sixth most common cancer in the world, with 30 percent of the cases being related to HPV infection. To make the connection, researchers exposed animal and human cell lines to cannabinoids. Researchers specifically looked at the cannabinoid receptors known as CNR1 and CNR2. Then the researchers injected mice with THC designed to mimic a human’s recreational cannabis use.
The researchers found in both the cell line and the mice THC interfered with a cellular pathway that regulates cell death. When the function is interfered with, cancer cells are able to grow unchecked. When looking at the blood plasma levels of 32 people with head and neck cancer, the research team detected cannabinoids in five of the 32 patients and their cellular pathway was interfered with, suggesting a link between growth and THC consumption.
“HPV-related head and neck cancer is one of the fastest growing cancers in the United States. While at the same time, exposure to marijuana is accelerating. This is a huge public health problem,” Joseph A. Califano III, MD, senior author and professor and vice chief of the Division of Otolaryngology in the Department of Surgery at UC San Diego School of Medicine, said.
HPV infections are common, with over 80 percent of the world’s population having some type of the virus before age 45. HPV vaccines protect against a majority of HPV-related cancers. The research team is now investigating whether CBD interferes with the same pathway.