Answer:
Uncontrollable cell division.
Step-by-step explanation:
Cancer is a disease which is caused when cells division is uncontrollable and spread into surrounding cells and tissues. Mutations in genes is also responsible for the cause of cancer because this mutation accelerate the rate of cell division or inhibiting normal controls on the system, such as programmed cell death. When the mass of cancerous cells grows with the passage of time, it turn into a tumor.