The evolution of cancer cells
All the cells in your body usually work together as a community. But if a cell acquires a gene mutation that makes it multiply when it should not, or helps it survive when other cells die, it has an advantage over the others. Eventually, the abnormal cells acquire mutations in more genes, causing uncontrolled growth. These abnormal cells have a competitive advantage over normal cells. This is like natural selection in evolution, where a species that produces more offspring has a better chance of survival.