Doctors study cancer cells’ origin

San Francisco Chronicle

SAN FRANCISCO — Stanford University doctors are trying a new tool to fight cancer. It’s a test that, by focusing on genetic analysis, could help doctors better understand a patient’s treatment needs.

Tthe test is designed to ferret out a key fact that helps determine which treatment would work best for each patient with advanced cancer, according to California-based Pathwork Diagnostics Inc., the test’s developer.

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. 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.

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 U.S. 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.

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.