Final answer:
Cancer is caused by the inactivation of tumor suppressor genes, such as p53, which normally regulate cell growth and division. When these genes are inactivated, cells can divide uncontrollably and form tumors.
Step-by-step explanation:
Cancer is a result of the inactivation of tumor suppressor genes. These genes normally regulate cell growth and prevent cells from dividing uncontrollably. When they are inactivated, cells can divide rapidly and form tumors. This is a multi-step process that involves the accumulation of mutations in genes that control cell division.
For example, one well-known tumor suppressor gene is p53. When p53 is inactivated, it can no longer prevent cells from dividing or induce cell death. As a result, cells can continue to divide and form tumors.