BREAST CANCER SERIES 2: Cancer Enigma Human cells normally grow and multiply to form new cells as the body needs them. This process is called cell division. When cells grow old and worn-out, they die, making way for these new cells. This process is directed by genetic materials called DNA. Changes to DNA, specifically, changes to the section of the DNA called genes can cause cancers. Proto-oncogenes, tumor suppressor genes and DNA repair genes are the three main gene types that are affected by these genetic changes which lead to cancers. Cancer is a large group of diseases that can start in almost any organ or tissue of the body when abnormal cells grow uncontrollably, go beyond their usual boundaries to invade adjoining parts of the body and/or spread to other organs. – World Health Organisation Proto-oncogenes are normal genes in the cell. They are responsible for cell division and preventing cells from dying, that is to say, they help keep the cells alive. These processes are ver