JMD publishes results of Tissue of Origin Test validation, reproducibility study

Pathwork Diagnostics, Inc., a privately held molecular diagnostics company focused on oncology, announced today that The Journal of Molecular Diagnostics (JMD) has published the results of a significant Tissue of Origin Test validation and reproducibility study. In the large blinded, multi-site study employing 462 formalin-fixed, paraffin-embedded (FFPE) tumor specimens, the Tissue of Origin Test results were in agreement with the available diagnosis in 89% of cases. These results show that the gene expression based Tissue of Origin Test can assist in accurately and reliably identifying the origin of metastatic or poorly differentiated tumors using FFPE tissue, which is the most common clinical specimen type used in testing of cancer tumors.

“The use of molecular technology to help determine the tissue of origin is a long awaited solution to an important clinical problem”

When a tumor's tissue of origin is not identified, patients may not receive the most appropriate tumor-specific, standard-of-care treatment. The study is the largest and most rigorously conducted validation of a gene expression based test for helping to identify a tumor's primary site using FFPE specimens.

"The use of molecular technology to help determine the tissue of origin is a long awaited solution to an important clinical problem," commented oncologist J. Scott Nystrom, M.D., Chief of Clinic Operations, Division of Hematology/Oncology at Tufts-New England Medical Center and one of the study authors. "This study demonstrates that gene expression analysis can be performed accurately and reliably on routine FFPE samples in a clinical setting."

Requiring very small amounts of FFPE tumor tissue, the Tissue of Origin Test measures the gene expression levels of more than 2,000 genes and compares the gene expression pattern of the specimen to that of 15 tissues in the test database, to indicate the most likely match.

The validation study published in JMD is titled "Validation and Reproducibility of a Microarray-Based Gene Expression Test for Tumor Identification in FFPE Specimens." In the study, 462 metastatic and poorly differentiated FFPE tumor tissue specimens from tissue banks, all of which had an available diagnosis identifying their tissue of origin as one of the 15 tissues in the test database, were analyzed using the Tissue of Origin Test. The Test results were compared to the available diagnoses and were in agreement in 89% of the cases. In addition, the study showed that an average of 12 cancer tissue types for each specimen could be ruled out, with >99% probability.

The Tissue of Origin Test received U.S. Food and Drug (FDA) clearance earlier this year for use with FFPE tissues. It is the only FDA-cleared molecular diagnostic test for tissue of origin and the most rigorously validated test of its kind. The test is available through the Pathwork Diagnostics Laboratory.