In a healthy body, cells grow and divide in a controlled manner to create new cells. These cells, in turn, grow old and eventually die for new cells to take their place. But sometimes this process goes wrong. When the new cells grow and divide in an uncontrolled manner, a mass of abnormal cells are created.
This mass of cells is commonly known as a tumour, which can either be benign (not cancerous) or malignant (cancerous).
To find out more about brain, breast, colorectal and lung cancer, as well as lymphoma, click on the tabs on the left hand side of the window.