Your body constantly produces new cells. Normal cells follow a typical cycle: They grow, divide and die. Cancer cells, on the other hand, don't follow this cycle. Instead of dying, they multiply and continue to reproduce other abnormal cells.
In contrast to normal cells, cancer cells don't stop growing and dividing, this uncontrolled cell growth results in the formation of a tumor. Cancer cells have more genetic changes compared to normal cells, however not all changes cause cancer, they may be a result of it