driver mutation

In a car analogy for a tumor, a driver mutation is the one sitting behind the wheel, steering toward growth. Out of the many mutations a cancer cell carries, only a handful actually push the cell to divide faster, survive longer, or spread; those are the drivers that give the tumor its forward momentum.

Technically, a driver mutation is a change that confers a selective growth advantage on the cell, so that cells carrying it outcompete their neighbors. Drivers typically hit oncogenes or tumor-suppressor genes, switching growth on or protection off. They are the targets cancer researchers care about most, because blocking a driver can stall the whole tumor.

Drivers are contrasted with passenger mutations, which a cancer cell also carries but which do not themselves promote growth. Telling drivers from passengers is hard, because a single tumor can contain thousands of mutations; statistics, recurrence across patients, and functional tests all help separate the few that matter from the many that simply came along for the ride.