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Pathwork Diagnostics: Three Studies to be Presented at American Society of Clinical Oncology Annual Meeting

5/31/2012 10:51:38 AM

Redwood City, CA, May 31, 2012 – Pathwork Diagnostics, Inc., a privately held molecular diagnostics company focused on oncology, announced today results of a study that indicated that TTF-1, a commonly used cell-staining tumor pathology test, does not correctly identify half of non-small cell lung carcinoma (NSCLC) cases in patients that present with metastatic or poorly differentiated cancer. The study will be presented at the upcoming 2012 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (June 1-5). A second study consists of a clinical validation of Pathwork’s Tissue of Origin Endometrial Test, while a third study examined the strength of the Tissue of Origin prediction and the subsequent prognosis of tested patients.

The Pathwork® Tissue of Origin Test is the only FDA-cleared, Medicare-covered molecular diagnostic for identifying tissue of origin. It uses a tumor's own genomic information to help pathologists and oncologists diagnose challenging cancer cases such as those that are metastatic or that have a complex clinical history.

In the study of thyroid transcription factor-1 (TTF-1) immunohistochemical staining, the Tissue of Origin Test was employed to evaluate the utility of TTF-1 in diagnosing non-small cell lung carcinoma (NSCLC) in cases that presented as cancer of uncertain primaries. In the study, the NSCLC cases were identified using the Tissue of Origin Test. The false negative rate of TTF-1 was 50%, indicating that half of the NSCLC cases identified by the Tissue of Origin Test were missed by TTF-1.

“In this small study, TTF-1 demonstrated a sensitivity of 50% and a specificity of 90%. Besides the high false negative rate, even more importantly the TTF-1 true positive rate was equal to the false positive rate, greatly limiting TTF-1’s predictive value in identifying NSCLC in CUP patients,” explained J. Scott Nystrom, M.D., Chief of Clinic Operations, Division of Hematology/Oncology at Tufts-New England Medical Center and one of the investigators. “While this report casts doubt on the utility of TTF-1 in CUP as to its predictive value in identifying or ruling out lung as a primary cell of origin, further confirmatory studies are warranted. Clinicians should consider gene expression testing in those cases where there remains doubt as to the cell of origin after the initial workup remains inconclusive.”

In a second study to be presented as a poster at ASCO 2012, a clinical validation of the Tissue of Origin Endometrial Test was conducted via a blinded study using a pre-specified algorithm and microarray data files for 75 metastatic, poorly differentiated or undifferentiated primary FFPE tumor specimens that had either a known clinical diagnosis of ovarian or endometrial cancer and belonged to one of the 14 ovarian and endometrial WHO histologic subtypes on the test panel. The Endometrial Test accurately identified the primary site for 94.7% of ovarian and endometrial cancers. Reproducibility in test results between three laboratories had a concordance of 94.3%.

“The Tissue of Origin Endometrial Test identified specific ovarian and endometrial cancer morphologies even when a clear distinction can be difficult to make by histologic criteria,” commented Daniel S. Kapp, M.D., Ph.D., Department of Radiation Oncology, Stanford University, and one of the investigators. “The test can aid in resolving an important differential diagnostic question in gynecologic oncology and may impact clinical management of these patients.”

In a third study presented as a poster at ASCO 2012, the relationship between the strength of the Tissue of Origin prediction (known as “Similarity Score”) and the subsequent prognosis of tested patients was examined in two observational studies. In both studies, there was a positive relationship observed between the strength of the prediction and the subsequent patient survival.

The posters, “Retrospective Analysis of Gene Expression Profiling and TTF-1 Staining in Cancer of Unknown Primary (CUP)”; “A Gene Expression Profile Test that Distinguishes Ovarian From Endometrial Cancers”; and “Estimation of Expected Survival Time Using Gene Expression Profiling for Tumor Site Origin” will presented in the Tumor Biology Session of ASCO, Monday, June 4, 1:15-5:15 pm, in S Hall A2.

The most rigorously validated test of its kind, the FDA-cleared Pathwork Tissue of Origin Test is available through the CLIA-certified, CAP-accredited Pathwork Diagnostics Laboratory. The Laboratory also provides the Tissue of Origin Endometrial Test, which is not FDA-cleared. To have a specimen processed by the Pathwork Diagnostics Laboratory or to learn more about the service, call Pathwork Diagnostics at (877) 808-0006 or visit

About Pathwork Diagnostics

Pathwork Diagnostics, Inc. is a privately held company based in Redwood City, CA, that develops and commercializes high-value molecular diagnostics for oncology. The company’s flagship Pathwork Tissue of Origin Test is the only FDA-cleared molecular test of its kind. For more information call toll-free (877) 808-0006 or visit

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