Pathwork Tissue of Origin Test Validation Study Published in Journal of Clinical...

Pathwork Tissue of Origin Test Validation Study Published in Journal of
Clinical Oncology

Largest Study on a Test that Identifies Tumors with Uncertain Origins
Demonstrates Unmatched Performance

REDWOOD CITY, Calif., March 30 /PRNewswire/ -- Pathwork Diagnostics, Inc., a
molecular diagnostics company focused on oncology, announced today that the
Journal of Clinical Oncology(JCO) has published the results of the Pathwork(R)
Tissue of Origin Test validation study in a paper entitled, "Multicenter
Validation of a 1,550-Gene Expression Profile for Identification of Tumor
Tissue of Origin." The results of the 547-specimen study showed that the test
has significant potential to reduce diagnostic uncertainty for poorly
differentiated, undifferentiated or metastatic tumors. To date, no other tests
in this category have undergone as large a clinical validation study or
produced such strong results.

"This study, which is the first of many clinical studies being performed,
clearly demonstrates the exceptional performance and robust science underlying
our test," said Deborah J. Neff, President and Chief Executive Officer of
Pathwork Diagnostics. "We believe the Tissue of Origin Test can benefit
physicians by allowing them to diagnose tumors with uncertain origins with
greater confidence because the test provides objective data and the ability to
both rule in and rule out tumor types."

To determine the tumor's origin, the Pathwork Tissue of Origin Test uses
microarray technology to measure the gene expression pattern, comprising more
than 1,500 genes, in a tumor with an uncertain origin and compare it to
expression patterns of a panel of 15 known tumor types, representing 90
percent of all solid tumors and 58 morphologies overall. In the multicenter,
blinded clinical validation study, which was used as the basis for the test's
FDA clearance in July 2008, the test examined 547 frozen tumor specimens from
patients diagnosed with one of the tumor types in the panel, all of which were
either metastatic, poorly differentiated or undifferentiated. The test
demonstrated 88% positive percent agreement (akin to sensitivity) and greater
than 99% negative percent agreement (akin to specificity) with available
diagnoses. Although the JCO paper only reported results for frozen tissue
samples, a separate validation study performed by Pathwork with FFPE
(formalin-fixed, paraffin-embedded) specimens showed similar performance. Both
the frozen and FFPE versions of the test are commercially available as a
service through Pathwork Diagnostics Laboratory.

The paper published in the American Society of Clinical Oncology's journal was
authored by Federico Monzon, M.D., Director of Molecular Diagnostics at The
Methodist Hospital in Houston, Texas. Dr. Monzon's results showed that the
test should become a valuable complement to currently available diagnostic
methods for tumors with uncertain origins. The abstract can be read online at
http://jco.ascopubs.org/ and the full paper is available for download on
www.pathworkdx.com.

About Pathwork Diagnostics
Pathwork Diagnostics, Inc., based in Redwood City, Calif., develops and
commercializes high-value molecular diagnostics for oncology. The company's
first test to market - the Pathwork(R) Tissue of Origin Test - utilizes
proprietary analytics and a companion Pathchip(R) microarray, which runs on
the proven Affymetrix GeneChip(R) System. For more information, call
1.877.808.0006 or visit www.pathworkdx.com.

Copyright (C) 2009 Pathwork Diagnostics, Inc. All rights reserved. Pathwork,
Pathchip, Pathwork Diagnostics, and the Pathwork Diagnostics and the Pathwork
Tissue of Origin logos are trademarks or registered trademarks of Pathwork
Diagnostics, Inc. Other names may be the trademarks of their respective
owners.

CONTACT:
Jane Woo
+1-415-608-1515
media@pathworkdx.com

SOURCE Pathwork Diagnostics, Inc.

Jane Woo of Pathwork Diagnostics, +1-415-608-1515, media@pathworkdx.com