Affymetrix Microarray Platform Granted Clearance from FDA for Gene Expression Diagnostic...

Affymetrix Microarray Platform Granted Clearance from FDA for Gene Expression Diagnostic Testing

Pathwork(R) Tissue of Origin Test is the First Gene Expression
Microarray-Based Test to Receive Clearance
SANTA CLARA, Calif.--(Business Wire)--
Affymetrix Inc. (Nasdaq:AFFX) announced today that the U.S. Food
and Drug Administration (FDA) has granted regulatory clearance to its
GCS3000Dx (GCSDx) platform for in vitro gene expression diagnostic
testing. The microarray system was granted clearance along with the
Pathwork(R) Tissue of Origin (TOO) Test from Pathwork Diagnostics Inc.
This test analyzes a tumor's gene expression profile to aid in
diagnosing the source of hard-to-identify tumors and is the first of
its kind to receive FDA clearance.

Pathwork is a member of the Powered by Affymetrix(TM) (PbA)
program, which includes 11 leading diagnostic companies. There are
currently more than 20 different molecular assay tests based on the
Affymetrix platform under development by Affymetrix and its PbA
Partners.

"We decided to work with Affymetrix because it is the market
leader in gene expression testing research and its 510(k)-cleared
microarray platform enabled us to develop a robust diagnostic," said
Deborah J. Neff, president and chief executive officer of Pathwork
Diagnostics. "The FDA's clearance of the Pathwork Tissue of Origin
Test reaffirms the importance of genomics and the role
microarray-based diagnostics can play in the battle against cancer."

"Together Affymetrix and Pathwork have developed and now bring to
market a very powerful tool to potentially improve cancer diagnostics
and subsequent treatment planning and outcome," said Kevin King,
president of Affymetrix. "The Pathwork Tissue of Origin Test is
supported by extensive analytical and clinical validation data. This
not only expands the menu on our diagnostic platform, but opens the
door for other gene expression-based diagnostic tests that are
currently being developed by Affymetrix and our PbA partners on the
GCSDx platform."

About Affymetrix

Affymetrix GeneChip(R) 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 1,700 systems have been shipped around the world and more
than 13,000 peer-reviewed papers have been published using the
technology.

Affymetrix is headquartered in Santa Clara, Calif., and has
manufacturing facilities in Sacramento, Calif., Cleveland, Ohio, 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 the company's
website at 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 commercial success of the Pathwork(R)
Tissue of Origin Test from Pathwork Diagnostics Inc. 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 past and future
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, 2007, 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(R) are
registered trademarks owned or used by Affymetrix Inc. Pathwork,
Pathwork Diagnostics and the Pathwork Diagnostics logo are trademarks
or registered trademarks of Pathwork Diagnostics Inc. Other names may
be the trademarks of their respective owners.

Affymetrix Inc.
Media:
Andrew Noble, 408-731-5571
Assistant Director, Corporate Communications
or
Investor:
Doug Farrell, 408-731-5285
Vice President, Investor Relations

Copyright Business Wire 2008