Question

How does cancer disrupt homeostasis?

Answer 1

Cancer is a form of abnormal development and transforms normal cells into cancerous cells. Usually, the cells of animals have control growth but in certain special circumstances, the cells begin to grow and multiply continuously forming a tumor or a cancerous growth.

Complete answer:
A tumor is defined as a neoplasm or abnormal growth or enlargement of new tissues due to unlimited and uncontrolled repeated divisions of some cells. It occurs usually after the age of 35 to 40 years but it may also occur at a young age.
The property and manner of cell division are the same for the cancer cell as for the normal cell. Cancer cells divide at the same or slower or faster rate than normal cells. But the cancer cells continue to divide unchecked resulting in an ever-increasing of cancerous cells and therefore the size of the tumor keeps growing. The continuously produced daughter cancerous cells never differentiate and ultimately start invading the neighboring areas. This finally breaks away from the primary tumor to migrate to other regions where also their divisions continue and secondary tumors are formed.
So cancer which leads to uncontrolled cell division forming tumors may lead to metastasis. Normal cells divide at a slow rate to replace old cells for maintaining homeostasis of the body. This is under the control of DNA in the nucleus of the cell. But in the case of cancer, this homeostasis is disturbed.

Note: Several genes called cellular oncogenes or proto-oncogenes identified in normal cells which when activated under certain conditions could lead to the oncogenic transformation of cells. The cells then lead to cancer.