1. WHAT IS CANCER?

The human body continually produces new cells every second of every day.  Cell death normally occurs in an ordered and systematic manner called ‘apoptosis'. This process is imperative in allowing new cells to replace the old cells.  Cancer occurs when the deoxyribonucleic acid (DNA) of a cell is damaged, such that the normal mechanisms that controls cell division is disrupted, and uncontrolled growth occurs (primary). These cells may acquire the ability to spread (metastasize) to other parts of the body through the lymphatics or blood system (secondaries).

A tumour or mass of cells is either benign or malignant.  A benign tumour doesn't have the ability to spread or metastasize to other parts of the body and therefore is not cancer. However, a benign tumour can still be dangerous due to its ability to grow and impair bodily functions by obstruction or pressure. In contrast a malignant tumour is cancerous and has the ability to metastasize to other parts of the body.  This ability to metastasize and form secondary tumours is the reason why cancer is so dangerous.

There are over 200 different types of cancers1, which all have unique characteristics, however all cancers occur due to DNA damage and subsequent uncontrolled cell division.  Different cancers arise due to the damage of DNA in different cell types.  For example, the damage of DNA in a testicle cell may lead to testicular cancer while the damage of the DNA in the kidney cell may lead to kidney cancer.  Furthermore, the damage of different cell types within an organ will lead to different cancer sub-types.  For example, the skin is the largest organ of the body and damage to basal cell and melanocyte, which are both types of skin cells, result in different types of cancer.