Cancer is a disease of the body cells in which their functioning and reproduction is uncontrolled. When a cell turns cancerous or malignant, it will not work properly, and it divides rapidly to produce more cells. A collection of cancerous cells is called a tumor. These cells are able to break away and are carried in the blood to other parts of the body, where they continue to grow.
Cancer can affect people of all ages, including fetuses, but the amount of risk increases with age. Cancer causes about 14% of the deaths all over the world. According a survey held in USA, 2.3 million people died of cancer in USA in 2007. Cancer can also affect all animals.
Usually, cells are replaced as they become old and inefficient. The development of these new cells is controlled so that the new cells are identical to the old ones. In cancer, so many abnormal cells are produced that they interfere with normal body functions and if untreated may cause very severe illness or death. The causes are not clear, but chemicals such as tar from cigarettes and many other substances are known to change normal cells into cancer cells. Cancer can be treated by surgery, or by very powerful DRUGS, or by radiation which damages the affected cells. Though people still die from cancer, many are surviving due to the improvement and success of modern treatments.
Some of the terms related to cancer are:
Carcinogen- A cancer causing substance. It attacks normal cells, and may eventually cause some of them to turn cancerous i. e. uncontrolled growth of cells.
Carcinoma- Cancer that starts to grow in tissue that forms the skin and lining of inner organs.
Sarcoma- Cancer that starts to grow in the tissue that forms the body's supporting structures, such as the bones and the cartilage.