The past 20 years have seen a rapid increase in our understanding of the biology of cancer. And, advances in understanding the genetics of cancer are beginning to have an impact on the clinical management of malignant disease. Many of the genetic changes that underlie malignant transformation of cells and/or that distinguish malignant clones can be used as markers to diagnose, monitor, or characterize various forms of cancer. The purpose of this volume is to assess the current status of genetic testing in cancer management both from the standpoint of those tests and genetic markers that are presently available and from the perspective of genetic approaches to cancer testing that are likely to have an impact on cancer management in the near future.