Identifying Cancer Cells Allows Tumor-Specific Treatment

A patient diagnosed with cancer must begin an immediate course of treatment to put the cancer into remission and prolong life. For the treatment to be effective, it must match the class of cancer that is present. In some cases the identification of the cancer cells can be an issue. The assumption is usually that the location of the cancer cells is a good identification tool, such as bladder, colon and breast cancer. If the patient has had cancer treatment in the past then the health care professional has to determine if the new tumor is metastasis of the old tumor or if this is a new type of cancer. A new test that can help determine the type of cancer cells has been cleared for marketing by the Food and Drug Administration.

Using a microarray technology, the Pathwork Tissue of Origin test compares genetic material from a patient’s tumor with genetic information of tumor types. The database used for testing the genetic information contains information on 15 common malignant tumor types including bladder, breast and colorectal. The accuracy of the tests is comparable to expert pathologists using current standards of technology.

Microarray technology can measure gene expression levels of large numbers of genes in one test. DNA fragments are placed on a slide then RNA, extracted from the tumor tissue and identified with a fluorescent marker are spread over the DNA "microarray." The RNA will bind to the complementary DNA strand and the amount of binding that occurs indicates how active the gene is. Pathwork’s proprietary software converts the scanned image to gene expression measurements. These patterns are compared to known gene expression patterns in the database that correspond to different tumor types. Identification of the tumor type allows for patient specific treatment using treatments that have proven most effective for that cancer type.

Dr. Daniel Schultz, director of the FDA Center for Devices and Radiological Health, said in a news release, “The clearance of the Pathwork test is another step in the continued integration of molecular-based medicine into standard practice.”

Pathwork Diagnostics is a molecular diagnostics company focused on oncology based in Sunnyvale, California. The PathChip used in the Pathwork Tissue of Origin test was custom designed for the company. The test will be available in a kit for clinical laboratories to run themselves and is currently available as a service through Pathwork Diagnostics Laboratory