Pathology and Laboratory Medicine

The explosion of knowledge and technology in cellular and molecular biology has universally affected medical research, clinical diagnosis, and treatment. The possibility of novel and innovative diagnostic approaches in all areas of the laboratory allows the pathologist to diagnose disorders with increasing accuracy, to predict populations at risk for the development of specific diseases, and to provide clinicians with an array of prognostic markers. No part of the laboratory is exempt from the influence of these technologies. In particular, the polymerase chain reaction, which allows detection of molecular abnormalities in very small patient samples, exemplifies this powerful technology. Molecular biologic evaluation of patients with cancer is one arena profoundly influenced by the polymerase chain reaction technique, since genetic changes that are detectable may have diagnostic or prognostic significance. Since normal protooncogene and tumor suppressor gene functions are required to maintain orderly differentiation and proliferation pathways in cells, it is reasonable