Will there be an mRNA vaccine for cancer?

Vaccines for cancer caused by some viruses already exist. But the search for a cure for cancer is ongoing. Scientists are now trialling mRNA cancer vaccines.

Before the coronavirus, most people had never heard of mRNA vaccines. The Pfizer-BioNTech and Moderna mRNA vaccines against COVID-19 were the first to be used in humans.

But the technology had been in development for years ― and among the diseases it was being tested on was cancer.

In mid-June, BioNTech announced that the first patient had been treated in its BNT111 phase 2 cancer vaccine trial. The vaccine uses the same mRNA technology as the Pfizer-BioNTech coronavirus vaccine.

"Similar to the way an mRNA vaccine against SARSCoV-2 works, an mRNA cancer vaccine trains your immune system to recognize a certain protein on the surface of cancer cells," said Anna Blakney, an assistant professor in the School of Biochemical Engineering at the University of British Columbia in Canada.

The goal of an mRNA cancer vaccine is to instruct the immune system to attack the cells expressing that protein.

"Basically, the idea is to get the immune system to recognize the cancer," said John

Cooke, medical director of the RNA Therapeutics Program in the Houston Methodist Hospital's DeBakey Heart and Vascular Center in Texas.

Cancer is a leading cause of death worldwide. It killed nearly 10 million people in 2020, according to the World Health Organization.

The reason cancer is able to grow and potentially kill a patient is that it is able to evade the immune system. "They fly under the radar of our immune system," said Cooke.

Tailoring vaccines

Vaccines are often thought to be preventative medicines, but the people in BioNTech's trials and other vaccine programs already have advanced melanoma.

For some types of cancer, like melanoma, it is possible to find a common change caused by the cancer among most people with the disease, Cooke told DW. This is the approach BioNTech has used. It has identified four cancer-specific antigens. More than 90% of melanomas in patients express at least one of these antigens.

But making a single vaccine to fight other types of cancer can be difficult.

"What's different in cancer is that most of the changes that are present in an individual cancer are unique," said David Braun, a physician-scientist at Harvard's Dana-Farber Cancer

Institute. "Very few are actually shared between patients."

This means that the vaccine needs to be tailored to the individual. Braun works with peptide vaccines in kidney cancer patients, and the targets that scientists can tell the immune system to attack differ from patient to patient, even though they all have the same type of cancer.

"What we've been trying to operationalize is a more personalized approach, a sort of precision immune therapy approach where we actually try to make a customized vaccine for each patient," Braun told DW. The same approach is also being used in