An mRNA vaccine, a cousin to the COVID vaccines that blunted the pandemic, has entered human trials as a treatment for lung cancer.

BNT116 is a striking example of how the conventional definition of a vaccine continues to expand. “When people hear the word vaccine, they think it means preventative, because every vaccine we’ve ever had — flu, measles, mumps, polio — those are all preventative vaccines,” said Dr. Joshua Brody, director of the Lymphoma Immunotherapy Program at the Tisch Cancer Institute at Mount Sinai Hospital in New York.