Scientists have discovered a surprising silver lining of COVID-19 infection.

A recent research conducted by experts at Northwestern Medicine Canning Thoracic Institute, which was published in the Journal of Clinical Investigation, discovered a link between contracting COVID-19 and the regression of cancer.

Though doctors at Northwestern University warned that the research is still in early stages, they’re hopeful that more tests could lead to new treatments in the future.

The team observed that the RNA from the SARS-CoV-2 virus can trigger the development of anti-cancer immune cells.

Called “inducible nonclassical monocytes (I-NCMs),” these immune cells showed the potential to attack cancer cells, opening up new possibilities for treatment. Rare compared to other types of monocytes, I-NCMs multiply when inflammation materializes, as it does during COVID-19 infection.

“We found that the same cells activated by severe COVID-19 could be induced with a drug to fight cancer, and we specifically saw a response with melanoma, lung, breast and colon cancer in the study,” said study author Ankit Bharat, MD, chief of thoracic surgery and director of the Canning Thoracic Institute.

“While this is still in the early stages and the effectiveness was only studied in preclinical animal models, it offers hope that we might be able to use this approach to benefit patients with advanced cancers that have not responded to other treatments.”

Creating this subset of immune cells begins when the RNA from COVID-19 sends a signal to the immune system that turns normal monocytes, a type of white blood cell, into I-NCMs. These can spread into the blood vessels and the surrounding tissue where tumors develop, a dual capability that distinguishes them from most other immune cells.

“Typically, immune cells called non-classical monocytes patrol blood vessels, looking for threats,” Bharat said. “But they can’t enter the tumor site itself due to the lack of specific receptors.

But the cells created during a severe bout of COVID still have a the specific receptor that lets them infiltrate the tumor environment.

“Once there, they release certain chemicals to recruit the body’s natural killer cells. These killer cells then swarm the tumor and start attacking the cancer cells directly, helping to shrink the tumor,” he said.

The study, conducted using both human tissue and animal tests, found that doctors can use a drug to create the same effect that COVID-19 RNA does.

“By manipulating that pathway through the drug, we might be able to help patients with many different types of cancers, particularly those with stage 4 cancers,” he said.

In preliminary tests, the compound reduced tumors by 60% to 70% in mice with human cancers.

While these findings are hopeful, Bharat notes that more research is called for.

“We are in the early stages, but the potential to transform cancer treatment is there. Our next steps will involve clinical trials to see if we can safely and effectively use these findings to help cancer patients.”

In related research, a case study published in the British Journal of Haematology in 2022 showed the surprising trajectory of a man diagnosed with terminal stage III lymphoma, presenting with tumors all over his body. Soon after his diagnosis, the man contracted COVID-19, which put him in the hospital for 11 days.

When the respiratory illness cleared, he went home. About four months later, his tumors did, too.