What causes cancer?

   The precise cause of cancer is not known. However, a vast amount of research over the past half century has helped us to make large strides in our understanding of this very complex and difficult disease. It now appears that most cancers develop because of a series of events that take place in a single cell of the body over a period of years. These  events convert this once normal cell into an abnormal cancer cell.

   Two types of factors contribute to this change: those that start the process of change, and those that continue the process once it has started. The first group of agents are called initiators, while the second group are called promoters. An initiator may be a chemical, radiation, or virus. A promoter may be a different agent in one of the same three groups.

   Research  has revealed that certain oncogenes produce a protein that establishes itself in the nucleus, or command post, of the cell. Other oncogenes produce a different protein found in the edges of the cell. It is possible that one of these proteins is produced by the initiator and the other by the promoter. Working hand in hand, these agents cause  the cell to multiply and spread without control.

   Chemicals that can produce a first or subsequent event in the transformation of a normal cell to a cancerous cell are called carcinogens. Carcinogens often require some other agent to work with them. These agents are called co-carcinogens. Over time, the action of one or several carcinogens (or co-carcinogens that are in the nucleus of a cell, especially those that control the multiplication of cells. When the genes that control cell reproduction finally change into an oncogene (or cancer gene), the body's normal control over the growth and multiplication of cells is lost, and a wild-growing cancer starts on its fateful course.