Clinical genomics in oncology

Abstract

Clinical Genomics • Genomics is the study of all nucleotide sequences, including structural genes, regulatory sequences, and non-coding DNA segments, in the chromosomes of an organism • Clinical genomics can be defined as the application of large-scale, high-throughput genomics technologies in clinical settings, such as clinical trials or primary care of patients Human Genome Project • The field of clinical genomics has grown enormously by the elucidation of the full sequence of the human genome and the characterization of all 25,000 human genes as well as the ability of large-scale surveys of gene expression, genetic polymorphisms single nucleotide polymorphisms and DNA copy numbers using microarray-based technologies Methodologies and Applications of Genomics • DNA microarray analysis is the most commonly used method to measure gene expression levels • This method has been most successfully applied to characterize human cancers in order to predict clinical outcomes and define clinically relevant subgroups of tumors Limitations • Most analyses have used gene expression levels to define broad group differences. A consequence, there remains a considerable diversity within these groups, and thus predictions often fall short of providing accurate predictions for individual patients • An extremely important step in obtaining reliable prognostic or predictive gene expression signatures is validation in an independent, sufficiently large cohort of patients. © 2008 Humana Press.