SUNNYVALE, Calif., Oct. 31 /PRNewswire/ -- Pathwork Diagnostics, a molecular diagnostics company focused on oncology, and City of Hope Hospital presented today the results from a meta-analysis examining the use of immunohistochemistry (IHC) to determine the origin of metastatic cancer at the second annual ASCO-NCI-EORTC Meeting on Molecular Markers in Cancer in Hollywood, Fla. In the meta-analysis, published peer-reviewed studies of the accuracy of IHC were reviewed. Researchers from Pathwork Diagnostics and the City of Hope Hospital, a leading cancer research and treatment center, found that various panels of IHC stains alone can perform poorly when attempting to determine the tissue of origin for metastatic tumors.
In the poster presentation, entitled "A Meta-Analysis of the Use of IHC Testing in Metastatic Disease: The Need for Integration of New Technologies," Dr. Larry Weiss, Chair, Division of Pathology, City of Hope, highlighted the results from the meta-analysis of five IHC studies published between 1993 and 2007 that quantified IHC performance in tissue identification. The results found that the blinded use of IHC panels identified the correct tissue of origin in only 66 percent of metastatic tumors, and 82 percent of the tumors in studies containing a blend of primary and metastatic tumors.
"Pathologists utilize IHC stains frequently to determine the origin of metastatic tumors; however, objective evidence as to its effectiveness has not been convincingly presented and these results confirm that there is a pressing clinical need for improved diagnostic methods," said Dr. Weiss. "The results also establish minimum performance requirements for any new diagnostic test intended to aid the pathologist and oncologist in tissue of origin determination as well as underscore the importance of well-designed validation studies that are statistically sound, adequately sized, and appropriately masked. It is only through such validation that new, genomic diagnostic tests can establish an appropriate place in the practice of evidence-based medicine."
"While it is important to note that tissue identification in the clinical setting utilizes clinical information in addition to IHC results, such as biopsy site, patient gender, age, clinical history and imaging techniques, the results of this analysis clearly demonstrate the opportunity for the Pathwork(R) Tissue of Origin Test to complement IHC in the clinic," said Deborah J. Neff, President and Chief Executive Officer of Pathwork Diagnostics.
About the Study
A literature search was conducted to identify all studies published since 1990 designed to quantify IHC performance in tissue determination. Five studies met the pre-defined criteria; more than 50 appropriately masked specimens and including more than three tissue types. These studies evaluated the successful identification from among three to seven different tissue types using a panel of seven to 10 different IHC tests. Data from the five studies were separated into two subgroups: metastatic tumors only (n=368 specimens), and blended studies that combined primary tumors and metastases (n=298 specimens). The meta-analysis found that IHC tests provided the correct tissue identification for 82.3% of the blended primary and metastatic samples and 65.6% of metastatic cancers, confirming the clinical need for improved diagnostic methods in tissue of origin determination.
About the Pathwork Tissue of Origin Test
The Pathwork Tissue of Origin Test uses a microarray to measure the expression pattern, comprising more than 1,500 genes, in the tumor and compares it to expression patterns of a panel of 15 known tumor types, representing 60 morphologies overall, to help determine the tumor's origin. Earlier this year, the test received FDA clearance, making Pathwork the first company of U.S. origin to receive clearance for a molecular diagnostics test under the U.S. Food and Drug Administration's (FDA) new IVDMIA (In Vitro Diagnostic Multivariate Index Assays) guidelines. In the clinical validation study submitted to the FDA, the test demonstrated 89 percent positive agreement (akin to sensitivity) and 99 percent negative agreement (akin to specificity) with available diagnoses of 545 metastatic, poorly differentiated and undifferentiated tumors. All 545 specimens included one of the 15 tissues on the test panel.
About Pathwork Diagnostics
Pathwork Diagnostics, Inc., based in Sunnyvale, 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. The test aids in determining a hard-to-identify tumor's origin so that standard-of-care, cancer-specific treatment can begin. The test is FDA-cleared as an in vitro diagnostic kit, while a functionally equivalent version of the test is also available through the CLIA-certified Pathwork(R) Diagnostics Laboratory. For more information, call 1.877.808.0006 or visit http://www.pathworkdx.com.
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