Cancer Detection and Prognosis
This chapter reviews some of the technologies used to detect the genetic and epigenetic changes that lead to alterations in the functions of the two main classes of genes recognized as playing roles in cancer (oncogenes and tumor-suppressor genes), and the use of these alterations as molecular markers for cancer detection and prognosis. Tumor-suppressor genes are normal genes that act as negative regulators of cell growth or other functions that may affect invasive and metastatic potential, such as cell adhesion and regulation of protease activity. The genetic alterations of oncogenes and tumor-suppressor genes that occur in cancer are classified into two main classes: germline and somatic alterations. Plasma or serum from cancer patients is analyzed to detect tumor markers such as oncogene mutations, microsatellite instability, hypermethylation of promoter regions and viral DNA. Banding analysis of metaphase chromosomes has been very useful for identifying causative chromosome rearrangements in leukemias and lymphomas.