A typical cancer cell has hundreds of mutated genes, but only a handful, known as drivers, are responsible for cancerous traits such as uncontrolled growth. Biologists have largely ignored the other mutations, believing they had little or no impact on cancer progression.
But a recent study from MIT, Harvard University, the Broad Institute, and Brigham and Women’s Hospital revealed, for the first time, that these so-called passenger mutations are not just along for the ride. When enough of them accumulate, they can slow or even halt tumor growth.
The findings suggest that cancer should be viewed as an evolutionary process whose course is determined by two opposing forces: driver-propelled growth and the gradual buildup of passenger mutations that inhibit tumors, says the paper’s senior author, Leonid Mirny, an associate professor of physics and of health sciences and technology. Furthermore, the researchers say, drugs that tip the balance in favor of the passenger mutations could offer a new way to treat cancer by beating it with its own weapon—mutations.