Serial analysis of gene expression (SAGE): application in cancer research

Serial analysis of gene expression (SAGE) is a powerful tool that allows digital analysis of overall gene expression patterns. SAGE provides quantitative and comprehensive expression profiling in a given cell population. Because SAGE does not require a preexisting clone, it can be used to identify and quantitate new as well as known genes. It works by isolating short fragments of genetic information from the genes expressed in the cell being studied. These short sequences, called SAGE tags, are linked together for efficient sequencing. SAGE is particularly well suited for organisms whose genome is not completely sequenced, because it does not require a hybridization probe for each transcript and allows new genes to be discovered. New modifications of SAGE now permit the analysis of gene expression in cell sub-populations or micro-anatomic structures, providing access to unexplored transcriptomes of normal and disease biology. Data derived using the SAGE technology have been used to identify tumor markers for a variety of cancers, including gastrointestinal cancer, lung and thyroid cancer, breast and ovarian cancer, neuroblastoma and glioblastoma, prostate cancer, and renal cell carcinoma. In this review we present an outline of the method and updated information on the applications of SAGE technology to various cancers.