To understand cancer we have to have some appreciation of human biology. Our body is made up of minuscule entities called cells; these are the basic unit of life. Similar types of cells come together to form our tissues (e.g.: muscle tissue, brain tissue etc.), groups of tissues form our organs and then organs come together to form systems (e.g.: cardio- vascular system, nervous system). Cancer is a disease of the smallest unit of our body – the cell. It develops when cells within our body obtain a series of defects that result in
their uncontrollable growth. These cells are thus able to grow and divide into multiple defective cells that form a mass called a tumour. This tumour takes over the tissue within which it formed and can then spread to surrounding tissue and ultimately to other parts of the body. This in essence is cancer – the rapid growth of cells within a tissue, which can spread to and destroy other tissues. Cancers are named according to where this process started so for instance lung cancer is the growth and spread of defective cells within lung tissue.