What causes cancer?

Uncontrolled functioning and reproduction of body cells cause cancer. When a cell turns cancerous or malignant, it does not work properly and 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. The abnormal cells increase manifold and interfere with normal body activity. If untreated, they may cause very severe illness or death. The causes of cancer are still not clear, but certain subtances like tar of cigarette are known to change normal cells to cancer cells. It can be treated by surgery, very powerful drugs or by radiation which damages the affected cells, when detected in early stages.