Ancient viruses that have been hiding inside human DNA for millions of years may help the body fight cancer, according to a new study by the Francis Crick Institute. The research showed that dormant remnants of these old viruses are activated when cancerous cells spiral out of control, unintentionally helping the immune system target and attack the tumor. The team hopes to use this discovery to design vaccines that could boost cancer treatment or even prevent it.
The researchers had noticed a connection between better survival from lung cancer and a part of the immune system called B-cells clustering around tumors. B-cells are responsible for producing antibodies and are better known for their role in fighting off infections, such as Covid. To figure out what they were doing in lung cancer, the team conducted a series of intricate experiments using samples from patients and animal tests. They found that the antibodies were recognizing remnants of what is termed endogenous retroviruses.
Retroviruses have the ability to insert a copy of their genetic instructions into our own DNA. Over time, some of these foreign instructions have been co-opted and serve useful purposes inside our cells, while others are tightly controlled to stop them spreading. However, chaos dominates inside a cancerous cell when it is growing uncontrollably and the once tight control of these ancient viruses is lost. This creates fragments of viruses that are enough for the immune system to spot a viral threat.
The antibodies then summon other parts of the immune system that kill off the “infected” cells – the immune system is trying to stop a virus but in this case is taking out cancerous cells. The researchers want to enhance this effect by developing vaccines to teach the body how to hunt for endogenous retroviruses. If successful, this could lead to therapeutic and preventative vaccines for cancer.
Dr Claire Bromley from Cancer Research UK said this study adds to the growing body of research that could one day see this innovative approach to cancer treatment become a reality. However, she added that more research was needed to develop a cancer vaccine.
The discovery of how ancient viruses can help fight cancer is a remarkable role reversal for retroviruses, which in their heyday might have been causing cancer in our ancestors due to the way they invade our DNA. Now, they may be protecting us from cancer, which is an intriguing finding. The Francis Crick Institute’s research shows how our bodies can use their own genetic makeup to fight diseases, and how understanding this could lead to new treatments and prevention methods.