Gene expression analysis is currently performed with the Affymetrix genechip technology. Oligonucleotide arrays are designed by Affymetrix and are synthesized based on sequence information available in public databases. To monitor gene expression, the mRNA from cells or tissue is biotin-labeled and hybridized to chips containing the oligonucleotide arrays. The specificity of hybridization is measured by laser confocal fluorescence scanning. This technology allows massive, parallel data acquisition and analysis.