Affymetrix Ushers in New Era of “In Situ Multiplex Gene Expression Analysis” with the Launch of QuantiGene ViewRNA – New Assays Detect Single RNA Transcripts in Individual Cells of Complex Samples

SANTA CLARA, Calif. – Affymetrix, Inc. (NASDAQ:AFFX) today announced the launch of QuantiGene(R) ViewRNA Assayformats, which enable a new era of “in situ multiplex gene expression analysis” by allowing drug screening of native cells and advancing the pace of biomarker disease research and stem cell studies. These in situ assays enable researchers to visualize gene expression in individual cells at an unprecedented level of sensitivity and speed.

QuantiGene ViewRNA Assays reliably quantitate gene expression while precisely localizing RNA trafficking within the cell at the single-copy level. The assays’ high specificity, bright signals, multiplex capability, and use across broad sample types, including tissues and blood, provide researchers with a new level of in situ gene expression analysis.

The five-hour QuantiGene ViewRNA Assay is capable of multiplex gene expression in 96- or 384-well formats for high-throughput phenotypic and reporter gene compound screening, thereby eliminating the arduous task of constructing reporter cell lines. The single-plex tissue assay is a practical alternative to immunohistochemistry (IHC), a widely used assay that is often challenging because antibodies are either unavailable or unreliable in the experimental system under investigation. The QuantiGene ViewRNA Assay uses a novel oligonucleotide probe design that can be universally applied to any gene of interest.

“In drug discovery, time is of the essence, and this assay allows us to know earlier in the process whether or not a compound is promising enough to pursue,” said Dan Garza, Senior Director of Biology at Proteostasis Therapeutics, Inc., which is currently using the assay to screen proteostasis modulators. “This assay represents a powerful new approach for quantification as well as analyzing heterogeneity and studying the kinetics of compound responses.”

“Researchers are excited about the multiplex assay because it allows them to simultaneously detect up to four individual transcripts in a cell’s native state without recombinant manipulation,” said George Bers, General Manager of the QuantiGene portfolio at Affymetrix. “The tissue-based assay is generating strong interest because it can detect genes in formalin-fixed, paraffin-embedded (FFPE) or cryogenic tissue sections. These sample types are normally difficult to use, and now researchers in drug discovery and development, molecular pathology, translational medicine, oncology, and neurosciences can pinpoint genes in specific cells of interest within complex tissues.”

QuantiGene ViewRNA Assays can also be used in a number of other applications, including:

Quantifying target mRNA following RNAi gene silencing

Biomarker validation testing

Stem cell characterization, differentiation, and quality control

Viral host cell interactions

Validating microarray gene expression results

For additional information, please visit our website.

About Affymetrix

Affymetrix technology is used by the world’s top pharmaceutical, diagnostic, and biotechnology companies, as well as leading academic, government, and nonprofit research institutes. More than 1,900 systems have been shipped around the world and more than 21,000 peer-reviewed papers have been published using the technology.

Affymetrix is headquartered in Santa Clara, Calif., and has manufacturing facilities in Cleveland, Ohio, and Singapore. The company has about 1,000 employees worldwide and maintains sales and distribution operations across Europe and Asia. For more information about Affymetrix, please visit www.affymetrix.com.

Forward-looking statements

All statements in this press release that are not historical are “forward-looking statements” within the meaning of Section 21E of the Securities Exchange Act as amended, including statements regarding Affymetrix’ “expectations,” “beliefs,” “hopes,” “intentions,” “strategies,” or the like. Such statements are subject to risks and uncertainties that could cause actual results to differ materially for Affymetrix from those projected. These and other risk factors are discussed in Affymetrix’ Form 10-K for the year ended December 31, 2009, and other SEC reports for subsequent quarterly periods.