Cancer is an evolutionary disease. The same forces that turned dinosaurs into birds turn normal cells into cancer: genetic mutations and traits that confer a survival advantage.
Evolution in animals is largely driven by mutations in the DNA of germ cells – the sperm and egg that fuse to form an embryo. These mutations may confer traits that differ from those of the offspring’s parents such as larger paws, sharper teeth or lighter hair color. If the change is beneficial, like a mutation that lightens the hair of a rabbit living in a snowy climate, the animal is better able to survive, mate and pass on its mutated gene to the next generation. Such changes accumulate over millions of years, eventually turning, for example, dinosaurs into bluebirds.
