Can Covid help kill cancer? Scientists make surprising discovery

At the height of the Covid-19 pandemic, some doctors made a strange discovery. The virus seemed to be helping kill cancer. Malignant tumors in cancer patients, who contracted a severe case of Covid, had either started shrinking or their growth was slowed. “We didn’t know if it was real, because these patients were so sick,” says Dr Ankit Bharat, chief of thoracic surgery at Northwestern University. “Was it because the immune system was so triggered by Covid-19 that it also started to kill cancer cells? What was it?”Dr Bharat and his team at the Northwestern Medicine Canning Thoracic Institute started digging deeper and published their findings in The Journal of Clinical Investigation on November 15, 2024. This could inspire new approaches to combat cancer metastasis, the process by which cancer spreads to other parts of the body.How our body fights cancerMonocytes are a type of immune cell, or white blood cell, which help the immune system by moving through the bloodstream and alerting other immune cells when they detect foreign cells or threats. Some monocytes can even help attract cancer-fighting cells to tumors. medium115691398However, cancer cells sometimes “trick” monocytes, using them to form a protective shield that hides the tumor from the immune system’s attack. Monocytes also can’t move through both blood vessels and surrounding tissue.But when SARS-CoV-2 (Covid-19 virus) is present in the body, these monocytes seem to behave differently. RNA from the Covid virus triggers the monocytes to transform into a rare type of immune cell, dubbed “inducible nonclassical monocytes (I-NCMs).” These cells naturally exist in low numbers and can usually only operate within blood vessels, not in tumors. The study found that these beneficial cells can be artificially boosted in healthy conditions using specific drugs. This allows them to enter tumors and metastatic sites, effectively changing the shielding effect and allowing the immune system to detect and fight the cancer more effectively.During inflammatory states, such as those caused by Covid-19 infections, organ transplants, or other immune system challenges, the number of these rare monocytes increase. By studying their behaviour in such scenarios, the researchers discovered how these cells could potentially be harnessed to fight cancer metastasis. When inside tumors, these cells produce a chemical that calls in natural killer cells, a type of immune cell that destroys cancer. This process works independently of T cells or B cells, which are often the target of traditional immunotherapies. medium115691436The approach was effective in mouse models of melanoma, lung, breast, and colon cancers. It even worked in genetically modified mice with weaker immune systems, reducing their vulnerability to cancer spread.How these new cells can fight cancer“What makes these cells so special is their dual capability,” Dr Bharat said in a press release. “Typically, immune cells called non-classical monocytes patrol blood vessels, looking for threats. But they can’t enter the tumor site itself due to the lack of specific receptors. In contrast, the I-NCMs created during severe Covid-19 retain a unique receptor called CCR2, allowing them to travel beyond blood vessels and 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.”The findings are promising as this will help in developing a treatment mimicking this immune cell formation. This could help treat some common cancers, including melanoma, lung, breast and colon cancer, Dr Bharat adds. The study was done using both human tissues and animal models. ShowQuotes medium nocaption115695171Why do we need this?Immunotherapy is one of the mostly widely used cancer treatments. This new treatment could help patients who develop a resistance to immunotherapy. In such cases, cancer may return after immunotherapy because the cancer cells are able to mutate and evade the treatment. Immunotherapy typically works by enlisting T cells to combat cancer. However, the cells activated by the Covid-19 virus can summon natural killer cells, which are even more effective at destroying cancer cells. “The most amazing thing is the effectiveness of these cells,” Dr Bharat says. Any treatment that comes from these findings would not replace immunotherapy, but would be used alongside it or as a secondary option if immunotherapy fails, he adds. medium115691467The findings are also unique to the Covid-19 RNA virus. Other RNA infections like influenza do not have the same ability to create cancer-fighting immune cells, researchers found. This function can be replicated in a drug, researchers found out, which would benefit patients with aggressive or advanced cancers. Dr Bharat says the cancer cells couldn’t develop a resistance to the immune cells, which makes things promising.Researchers are hoping to begin a clinical trial for the treatment of cancer patients. “We are in the early stages, but the potential to transform cancer treatment is there,” Dr Bharat explains.