AFFX Affymetrix, Inc.

Affymetrix Inc. (Nasdaq:AFFX) announced today that its GeneChip� technology will form the foundation of the new molecular cytogenetic service offering by Laboratory Corporation of America� Holdings (LabCorp�) (NYSE:LH). LabCorp, an industry leader in molecular diagnostic testing, is making the service available to customers across the United States. The new LabCorp cytogenetic service will correlate deletions, gains and other chromosomal rearrangements with congenital diseases such as autism, mental retardation and developmental delay in children. The Affymetrix genotyping technology was designed to measure genotype, copy number changes and loss of heterozygosity (LOH) information across the entire genome, enabling customers to discover more causative aberrations than with karyotype or FISH technologies. �This new testing based on the Affymetrix platform will offer unparalleled resolution for the detection of the etiology of mental retardation, developmental delay, autism and other clinically significant changes and underscores LabCorp�s commitment to providing physicians and patients with the highest-quality technology advances to meet their clinical needs,� said Myla Lai-Goldman, M.D., executive vice president, chief scientific officer and medical director of LabCorp. �Affymetrix is pleased to partner with LabCorp to demonstrate how our GeneChip technology can improve cytogenetic analysis,� said Ramsey Hashem, senior vice president of global commercial operations at Affymetrix. �We believe the Affymetrix platform is uniquely positioned to become the gold-standard tool in cytogenetic analysis because it provides a higher-resolution view of the entire genome, enabling customers to examine genetic variation frequently associated with congenital diseases.� About LabCorp Laboratory Corporation of America� Holdings, a S&P 500 company, is a pioneer in commercializing new diagnostic technologies and the first in its industry to embrace genomic testing. With annual revenues of $3.6 billion in 2006, over 25,000 employees nationwide, and more than 220,000 clients, LabCorp offers clinical assays ranging from routine blood analyses to HIV and genomic testing. LabCorp combines its expertise in innovative clinical testing technology with its Centers of Excellence: The Center for Molecular Biology and Pathology, National Genetics Institute, Inc., ViroMed Laboratories, Inc., The Center for Esoteric Testing, DIANON Systems, Inc., US LABS, Esoterix and its Colorado Coagulation, Endocrine Sciences, and Cytometry Associates laboratories. LabCorp conducts clinical trial testing through its Esoterix Clinical Trials Services division. LabCorp clients include physicians, government agencies, managed care organizations, hospitals, clinical labs and pharmaceutical companies. To learn more about LabCorp, please visit: www.labcorp.com. Each of the above forward-looking statements is subject to change based on various important factors, including without limitation, competitive actions in the marketplace and adverse actions of governmental and other third-party payors. Actual results could differ materially from those suggested by these forward-looking statements. Further information on potential factors that could affect LabCorp�s financial results is included in the Company�s Form 10-K for the year ended December 31, 2006, and subsequent SEC filings. About Affymetrix Affymetrix GeneChip� microarray technology is the industry-standard tool for analyzing complex genetic information. After inventing microarray technology in the late 1980s, Affymetrix scientists have been dedicated to developing innovative products that provide researchers with a more complete view of the genome. These products continue to accelerate genetic research and enable scientists to develop diagnostics and tailor treatments for individual patients by identifying and measuring the genetic information associated with complex diseases. Today, Affymetrix technology is used by the world�s top pharmaceutical, diagnostic and biotechnology companies, as well as leading academic, government and not-for-profit research institutes. More than 1,600 systems have been shipped around the world and more than 10,500 peer-reviewed papers have been published using the technology. Affymetrix is headquartered in Santa Clara, Calif., and has manufacturing facilities in Sacramento, Calif., and Singapore. The company has about 1,100 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, including, but not limited to: risks and uncertainties relating to the agreement with Laboratory Corporation of America� Holdings discussed in this press release; risks of the company�s ability to achieve and sustain higher levels of revenue, higher gross margins and reduced operating expenses; uncertainties related to technological approaches, manufacturing and product development; personnel retention; uncertainties related to cost and pricing of Affymetrix products; dependence on collaborative partners; uncertainties related to sole-source suppliers; risks associated with acquisitions; uncertainties relating to FDA and other regulatory approvals; competition; risks relating to intellectual property of others and the uncertainties of patent protection and litigation. These and other risk factors are discussed in Affymetrix� Form 10-K for the year ended December 31, 2006, and other SEC reports, including its Quarterly Reports on Form 10-Q for subsequent quarterly periods. Affymetrix expressly disclaims any obligation or undertaking to release publicly any updates or revisions to any forward-looking statements contained herein to reflect any change in Affymetrix� expectations with regard thereto or any change in events, conditions or circumstances on which any such statements are based. NOTE: Affymetrix, the Affymetrix logo and GeneChip� are registered trademarks owned or used by Affymetrix Inc.