Viruses hidden in human DNA for millions of years could help the body fight cancer, scientists say.
Researchers at the Francis Crick Institute study lung cancer – Leading cause of cancer-related death worldwide – Learn why some patients respond better to immunotherapy than others.
They found that when a person has cancer, viral genes passed down from our ancestors can be “awakened” and join in the fight against the tumor.
They hope this finding can be used to develop vaccines for cancer treatment.
Read more: How cancer vaccines work
The research team investigated why patients with antibody-producing B cells surrounding their tumors tended to respond better to immunotherapy.
They found that these B cells enhanced the immune response to cancer because they produced antibodies that bound to the tumor.
This is similar to how B cells produce antiviral antibodies after flu or COVID infection.
The key to this response is hidden in ancient viral DNA, called endogenous retroviruses (ERVs).
This viral DNA is passed down from our ancestors’ historical infections and makes up about 5 percent of human DNA.
It normally lies dormant, but when a person has cancer, the viral gene is awakened.
Viral fragments are sufficient to trigger an immune response. The body thinks the tumor cells are infected and attacks them accordingly.
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The study, published in the journal Nature, looked at immune cell activity in mice with lung cancer as well as tumor samples from lung cancer patients. It is part of the TRACERx study, funded by Cancer Research UK.
George Kassiotis, head of the Retroviral Immunology Laboratory at the Crick, said: “ERVs have been hiding in the human genome as viral footprints for thousands or millions of years, so it’s important to think that diseases in our ancestors might hold the key to treating them. Fascinating. Today’s disease.
“With more research, we could seek to develop a cancer treatment vaccine consisting of activated ERV genes to boost antibody production at cancer sites in patients and hopefully improve the efficacy of immunotherapy.”