PATHWORK DIAGNOSTICS TISSUE OF ORIGIN TEST
Overview
The Pathwork Tissue of Origin Test is a molecular diagnostic tool designed to assist in identifying the primary site of difficult-to-classify tumors, including poorly differentiated, undifferentiated, and metastatic cancers. It utilizes microarray-based RNA profiling to measure gene expression patterns in a patient’s tumor specimen and compares them against a comprehensive database of 15 known malignant tumor types. This gene expression-based approach provides objective, probability-based scores to help clinicians make more informed diagnostic and treatment decisions when conventional pathology alone is insufficient. The test was initially cleared by the FDA for use with fresh-frozen tissue samples in 2008 and subsequently for formalin-fixed, paraffin-embedded (FFPE) tissue specimens in 2010. It was available both as an in vitro diagnostic (IVD) kit for clinical laboratories and as a service through Pathwork’s CLIA-certified laboratory.
Reviewed by Pouyan Golshani, MD — Interventional Radiologist
Key Features
- Microarray-based gene expression profiling
- Compares tumor gene expression to a database of 15 known tumor types
- Aids in diagnosis of poorly differentiated, undifferentiated, and metastatic tumors
- Works with fresh-frozen and FFPE tissue specimens
- Provides objective, probability-based similarity scores
- FDA-cleared as an in vitro diagnostic (IVD) kit
- Available as a CLIA-certified laboratory service
- Utilizes proprietary Pathchip microarray and analytics
Use Cases
- Identifying the primary site of cancer of unknown primary (CUP)
- Aiding in the diagnosis of poorly differentiated tumors
- Aiding in the diagnosis of undifferentiated tumors
- Aiding in the diagnosis of metastatic tumors
- Guiding site-specific treatment decisions in oncology
- Providing molecular classification support when conventional pathology is insufficient
What Physicians Need to Know
Consider the Pathwork Tissue of Origin Test for patients with poorly differentiated, undifferentiated, or metastatic tumors where the primary site is uncertain after initial diagnostic workup, including IHC and imaging. The test provides objective genomic information that can guide more targeted treatment decisions, potentially improving patient outcomes and avoiding unnecessary toxicities. Always interpret the results in the context of the patient's complete clinical history and other diagnostic findings. Be aware that the test is not intended to establish the origin of tumors that cannot be diagnosed by current clinical practice, nor to predict disease course, survival, or treatment efficacy, or to distinguish primary from metastatic tumors.
The Pathwork Tissue of Origin Test can be integrated into clinical workflows either by performing the test in-house using the FDA-cleared IVD kit and Affymetrix GeneChip System, or by utilizing Pathwork Diagnostics' CLIA-certified laboratory service. Ensure proper protocols for tissue specimen processing (FFPE or fresh-frozen) and data transmission are followed for accurate analysis and report generation. The system is designed to complement existing diagnostic technologies like immunohistochemistry and imaging.
Details
| Category | Oncology AI, Pathology AI |
| Pricing | Contact for pricing — Not publicly available; offered as a laboratory service or IVD kit. |
| Deployment | On-premise (IVD kit for clinical labs) or cloud-based (via CLIA-certified lab service) |
| Compliance | |
| BAA Available | Unknown AI-estimated |
| HIPAA Compliant | Unknown AI-estimated |
| FDA Status |
1 AI-estimated The Pathwork Tissue of Origin Test received 510(k) clearance (K080896) from the U.S. Food and Drug Administration (FDA) on July 30, 2008, for use with fresh-frozen tumor samples. A subsequent 510(k) clearance (K092967) was granted in 2010 for its use with formalin-fixed, paraffin-embedded (FFPE) tissue specimens. |
| Integrations | |
| EHR | Not specified |
| Specialties | Oncology, Pathology |
What the Web Says
The PATHWORK DIAGNOSTICS TISSUE OF ORIGIN TEST is a microarray-based gene expression test designed to help identify the primary site of origin for difficult-to-diagnose tumors, including metastatic, poorly differentiated, or undifferentiated cancers. It compares the gene expression patterns of a patient's tumor to a database of 15 known tumor types. The test received FDA clearance in 2008 for fresh-frozen samples and in 2010 for formalin-fixed paraffin-embedded (FFPE) tissue. Studies have shown that the test can significantly aid pathologists and oncologists in making more accurate diagnoses and guiding treatment decisions for cancers of unknown primary (CUP).
Overall: MixedStrengths
- High accuracy in determining tissue of origin, with studies showing 94.7% overall accuracy and 87.8% sensitivity and 99.4% specificity in frozen tissue samples.
- Can identify probable origin in a significant percentage of Carcinoma of Unknown Primary (CUP) cases (e.g., 73% in one study, 96% in another).
- Helps oncologists prescribe more appropriate, targeted therapies and avoid less-specific chemotherapies, potentially improving patient survival and enabling enrollment in relevant clinical trials.
- Pathologists have changed their initial or unresolved differential diagnoses based on the test results in over half of the cases.
- Available as an in vitro diagnostic (IVD) kit for clinical laboratories to run themselves, and also as a service through a CLIA-certified laboratory.
- Covered by Medicare nationwide since 2011.
Limitations
- Analysis of accuracy in CUP cases is limited due to the lack of a reference diagnosis.
- The test may confound tissue and cell types for off-panel and CUP samples, requiring careful clinicopathologic assessment for interpretation.
- Some experts believe that comparisons of its accuracy to immunohistochemical staining can be overreaching, as the case types studied may differ.
- Does not cover diagnoses for leukemia types.
- The test was initially cleared in 2008 and 2010, and the most recent studies cited are from 2011-2012, suggesting the information may not reflect the latest advancements in diagnostic technology.
- No reviews or opinions from healthcare IT, tech reviewers, Reddit, G2, or Capterra were found in the search results, indicating a lack of public or IT-specific feedback.
Last updated: 2026-07-20
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Pathwork Diagnostics at the ASCO Annual Meeting: Part 1
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