Every day, every cell in the body picks up one or two genetic mutations. Luckily, cells have a whole battery of strategies for fixing these errors. But most of the time, even if a mutation doesn’t get fixed — or doesn’t get fixed properly — there are no obvious functional implications. That is, the mutation isn't known to impair the function of the cell. Some mutations, however — called “driver” mutations — do impair the cell, leading to cancer, aging, or other types of diseases.