Using Serial Analysis of Gene Expression to identify tumor markers and antigens

Tumor markers and antigens are normally highly expressed in malignant tissu e, but not in the surrounding normal tissue. Serial Analysis of Gene Expres sion (SAGE) is a technology that counts mRNA transcripts and can be used to find those genes most highly induced in malignant tissues. SAGE produces a comprehensive profile of gene expression and can be used to search for tum or biomarkers in a limited number of samples. Public sources of SAGE data, in particular through the Cancer Genome Anatomy Project, increase the value of this technology by making a large source of information on many tumors and normal tissues available for comparison. Although the perfect tumor-spe cific gene does not exist, the differences in gene expression between tumor and normal can be exploited for therapeutic or diagnostic purposes.