During the COVID-19 pandemic, oncologists noticed something strange. Some people with cancer who developed severe COVID infections showed an unexpected side effect: Their cancer appeared to regress.
Exploring the link
Ankit Bharat, MD, chief of thoracic surgery and director of the Canning Thoracic Institute at Northwestern University, decided to dig deeper into this finding.
Normally, when cancer spreads, it creates mechanisms to protect itself from the person’s immune system. One of the ways it does that is by retraining the body’s white blood cells to prevent the immune system from killing the cancer cells.
But Dr. Bharat’s team found that the RNA of the COVID virus could make certain changes in those white blood cells so they did not protect the cancer. Instead, the study found they brought in specialized immune cells, called inducible nonclassical monocytes (I-NCMs), that kill cancer cells.
The process begins when the RNA from the virus activates signals in the immune system. These signals cause the transformation of an ordinary type of white blood cell into I-NCMs. These newly formed cells can move into blood vessels and the surrounding tissue where tumors grow, something most other immune cells can’t do.
Lock and key
Typically, immune cells can’t enter the tumor site due to the lack of specific receptors. But the I-NCMs created during severe COVID-19 have a unique receptor called CCR2, allowing them to travel beyond blood vessels and infiltrate the tumor environment.
Once there, they release 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.
Dr. Bharat’s team also looked at influenza, another RNA virus, but it didn’t have the same effect. He explains that when the body is infected by an RNA virus, the RNA is in the bloodstream for a period of time. White blood cells have a receptor that you can think of as a lock to a door. The RNA of the COVID virus is a perfect key for that lock, but the influenza RNA is not.
Translating to treatment
It’s important to note that people with cancer should not try to get a COVID-19 infection. Many cancer treatments weaken the body’s ability to fight off infections, and a history of cancer increases the risk of serious illness and death from COVID-19.
Fortunately, there is a drug that can mimic the cancer-fighting effect of the RNA. Early research shows that it’s effective for melanoma, lung, breast, and colon cancer. Although the drug already exists, it does not have a current indication or FDA approval, but it will help shorten development time.
Dr. Bharat’s team hopes that, with further research, they can develop therapies that specifically target these cells to treat cancers that are currently difficult to manage. This could lead to new treatment options for patients who have exhausted all other possibilities.
Bottom Line Health interviewed Ankit Bharat, MD, chief of thoracic surgery and director of the Northwestern Medicine Canning Thoracic Institute.
© Nikola Stojadinovic | Getty Images
New research sheds light on a surprising connection between COVID-19 and cancer regression.
Ankit Bharat, MD
Northwestern University Feinberg School of Medicine
