Study: Diagnostic Test Could Pinpoint Origins of Tumors

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http://www.sfgate.com/cgi-bin/article.c ... 10HP8S.DTL

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Pathologists at the Stanford University School of Medicine are trying out a new test from a Sunnyvale company that could give cancer patients a better chance of getting the most effective treatment.

The test, developed by Pathwork Diagnostics Inc., is part of a growing drive to use genetic analysis and molecular markers to guide the choice of therapies in many disease types. Pathwork's test was designed to ferret out a key fact that helps determine which treatment would work best for each patient with advanced cancer.

Doctors need to know where in the body the cancer first struck before it spread - whether it was the breast or lungs or some other organ. That's because the best remedies vary depending on which organ gave rise to the original tumor. A secondary tumor found in the lung may not respond to a lung cancer drug if it is actually an offshoot of breast cancer.

But the original site of cancer is sometimes hard to discover after the disease has spread to other parts of the body. Cancer cells can lose the usual shape and appearance of cells from the tissue they came from, once they have migrated to another organ and formed the seeds of new tumors.

Diagnosticians now use a range of tools to track metastatic cancer to its origin. The methods include the examination of tumor cells under the microscope; X-rays and other medical imaging exams; and lab tests to detect proteins in tumor specimens that are characteristic of certain organs. But those methods can still leave the question unanswered.

Pathwork, a private company founded in 2006, looked for conclusive genetic signatures that would peg a tumor cell as a descendant of cells from one of 15 specific organs or tissues. The company started offering its Tissue of Origin Test to doctors through its own lab in April. Pathwork is also applying for Food and Drug Administration approval to sell the diagnostic test as a kit that could be used by other labs, such as hospital pathology units.

In the meantime, the pathology lab at Stanford's medical school is trying the test for free. Doctors will still use the more traditional tests, but they'll compare Pathwork's results to see if they jibe with the other evidence.

"Hard-to-identify tumors are particularly challenging for physicians," said Dr. Iris Schrijver, the medical school's director of molecular pathology. "We are looking forward to evaluating the Tissue of Origin Test's potential to provide diagnostic answers that can help further guide patient care in these challenging cases."

Each year in the United States, doctors face about 200,000 cancer cases that have an uncertain primary tumor site, said Pathwork's chief medical officer, Dr. David Henner. The Pathwork test, which uses GeneChip technology made by Affymetrix of Santa Clara, scans the tumor sample to see which of 1,500 genes are active. The pattern of active genes points to the organ or tissue type where the tumor originated, Henner said.

In a study evaluating the accuracy of the test in identifying original tumor sites, the company's gene-based assay produced the same finding as conventional diagnostic methods in 89 percent of the 477 samples examined, Pathwork has reported.

David Craford, Pathwork's vice president of commercial operations, said the test is being offered at a list price of $3,750. The company is in discussions with the Medicare system and private insurance providers on conditions for reimbursement, he said. Craford said the worldwide market for such tests could reach $600 million, and Pathwork hopes to capture a significant share of those sales.

A San Diego company, AviaraDx, also is marketing a test to detect the origins of unknown cancers. The Aviara CancerTYPE ID test is based on an evaluation of 92 genes. A similar test called CupPrint was developed in the Netherlands by a company called Agendia.

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(San Francisco Chronicle, By Bernadette Tansey, Chronicle Staff Writer, May 8, 2008)

Disclaimer:

The information contained in these articles may or may not be in agreement with my own opinions. They are not posted as medical advice of any kind.