Ancient Viruses Help Fight Cancer: A Groundbreaking Discovery

The research team that made the discovery wants to capitalize on this study to design vaccines to stimulate cancer treatment or even prevent it.

Remnants of ancient viruses – which have been hidden in human DNA for millions of years – help the body fight cancer, scientists say.

The study carried out by the Francis Crick Institute showed that the latent remnants of these old viruses are awakened when cancer cells get out of control.

This inadvertently helps the immune system target and attack the tumor.

The team wants to capitalize on this discovery to design vaccines to boost cancer treatment or even prevent it, they write AFP.

Researchers had seen a link between better survival in lung cancer and a part of the immune system called B cells that cluster around tumors.

B cells are the part of our body that produces antibodies and are best known for their role in fighting infections such as Covid.

What exactly these did to lung cancer was a mystery, but a series of complicated experiments using patient samples and animal tests showed that they were still trying to fight viruses.

“It turned out that the antibodies recognize the remnants of what are called endogenous retroviruses,” Professor Julian Downward, associate director of research at the Francis Crick Institute, told the BBC.

Retroviruses have the “ability” to “sneak a copy of their genetic instructions inside us”.

However, chaos reigns inside a cancer cell when it grows out of control, and the once strict control of these ancient viruses is lost.

These ancient genetic instructions are no longer capable of resurrecting whole viruses, but they can create virus fragments that are sufficient for the immune system to detect a viral threat.

“The immune system is tricked into thinking the tumor cells are infected and trying to eliminate the virus, so it’s a kind of alarm system,” said Professor George Kassiotis, head of the department of retroviral immunology at the biomedical research centre.

Antibodies call other parts of the immune system to eliminate “infected” cells – the immune system is trying to stop a virus, but in this case it is eliminating cancer cells.

Professor Kassiotis says it is a remarkable reversal of the role of retroviruses which, in their heyday, “could have caused cancer in our ancestors” because of the way they invade our DNA, but now protect us from cancer.

The study, published in the journal Nature, describes how this happens naturally in the body, but researchers want to improve the effect by developing vaccines that teach the body how to hunt endogenous retroviruses.

“If we can do this, then we can not only think about therapeutic vaccines, but also about preventive vaccines,” said Professor Kassiotis.

The research was carried out as part of the TracerX study, which has tracked lung cancers in unprecedented detail and which this week showed the cancer’s “almost infinite” ability to evolve. This led the researchers who led the study to call for more attention to be paid to cancer prevention because it is so difficult to stop.

Dr Claire Bromley, from Cancer Research UK, said: “We all have ancient viral DNA in our genes, passed down from our ancestors, and this fascinating research has highlighted the role it plays in cancer and how our immune system the immune system can recognize and destroy cancer cells.”

She said “more research” is needed to develop a cancer vaccine, but “nevertheless, this study adds to the growing body of research that could one day see this approach innovative treatment against cancer becoming a reality”.