Final answer:
A tumor is a mass of cancerous cells that have begun to grow and divide uncontrollably due to DNA damage. Tumors may be benign or malignant, with the latter having the potential to invade other tissues, spread to different parts of the body, and eventually cause death.
Step-by-step explanation:
A tumor is a cluster of cancerous cells that have lost control of their growing. Cancer is a complex disease characterized by unregulated cell growth. When cells in the body sustain DNA damage, which could be caused by factors like radiation or carcinogens, they can begin to divide uncontrollably. This leads to the formation of a mass known as a tumor.
Tumors can be either benign, where they do not spread to other tissues, or malignant, where they invade nearby tissues and, through a process known as metastasis, can spread to different parts of the body. These cancerous tumors are harmful as they impair the normal function of organs and consume essential nutrients, which are then diverted away from healthy cells. Moreover, when cancer affects areas like the bone marrow, it can lead to the production of dysfunctional blood cells, as the process of cell division occurs prematurely. Over time, the rapid proliferation of cancerous cells and their spread to various parts of the body can lead to critical organ failure and potentially death.