[Implications of molecular biology in clinical oncology.]

In the past two decades there has been an ever increasing understanding of the molecular biology of cancer formation. It is now well established that the development of neoplasia is due to the accumulation of alterations in specific genes. Alterations in both oncogenes and tumor suppressor genes are now recognized as crucial factors in this process. The knowledge that these studies have brought forth is starting to have effects on clinical oncology. Not only may it help in diagnosing patients who could benefit from prophylactic measures, but also open possibilities of diagnosing cancer sooner than is done today. Furthermore, the assessment of specific genetic alterations can help to define prognosis more accurately and enable clinicians to target treatment more effectively. Because of this it is important that clinicians have a basic understanding of the molecular mechanisms involved in carcinogenesis. The purpose of this article is to give such an understanding and review the studies that have made significant contributions to present day knowledge. Finally, the clinical implications of these studies are addressed.