Cancer is a disease characterized by the uncontrolled growth and division of abnormal cells in the body. These abnormal cells often form masses called tumors, which can be benign (non-cancerous) or malignant (cancerous). Malignant cancer cells have the ability to invade nearby tissues and spread to other parts of the body, a process known as metastasis. Cancer arises because of genetic changes (mutations) in cells that disrupt normal cell growth and death, leading to continuous proliferation and survival of transformed cells. There are many types of cancer, as cancer can develop in almost any tissue or organ in the body.
Key Features of Cancer
- Cancer results from gene mutations that cause cells to grow uncontrollably.
- Cancer cells can invade nearby tissue and spread throughout the body.
- Cancer can form tumors or, in cases like leukemia, involve abnormal blood cells.
- Some mutations causing cancer are inherited, but most occur during a person's lifetime.
- Cancer is not one disease but rather a group of related diseases with similar properties.
Modern Understanding
Cancer is now understood as a disease of transformed cells that not only grow uncontrollably but also evolve through natural selection, which allows them to adapt and survive in different environments in the body, making treatment challenging.
In summary, cancer fundamentally is the uncontrolled and abnormal growth of cells that can invade and disrupt normal body functions through growth and spread.