Although cancer is usually thought of as one disease, it is in fact more than 200 different diseases. For many of these cancers, no definite cause is known. There is no one single cause. In fact, cancer remains something of a mystery. But new clues and solid research are greatly increasing our understanding.
The Role of Oncogenes One of the most exciting and important developments has been the recent discovery that some normal genes may be transformed into genes that promote the growth of cancer. These have been called oncogenes, the prefix onco meaning tumor . This discovery has led to much research, better understanding of how cancer develops and insights into methods of prevention, detection and treatment.
What usually stops the normal genes from being transformed are other genes called suppressor genes. If they don't do their job properly or are missing altogether, the cancer-producing action of the oncogene may not be suppressed.
The Implications for Screening All this new information raises the possibility that we may soon be able to test individuals, for example with a blood test, to discover whether a specific oncogene is present and if the suppressor gene is defective or absent. The presence of certain oncogenes may even give us information about how likely it is that a cancer will spread. We soon may be able to identify people with a higher risk for cancer and possibly carry out other intensive detection and screening methods. Techniques for testing for oncogenes have been developed recently and are beginning to be available for general use. This new knowledge is already used in the study of familial (inherited) polyps of the colon.
