A Possible Blood Test for Cancer

January 05, 2011

Efforts to develop a simple blood test that can detect the presence and spread of cancer are poised to take a big step forward in 2011 now that Johnson & Johnson Co. is combining its efforts in this area with Massachusetts General Hospital. The two organizations Monday announced a collaboration to create a new technology for capturing, counting and characterizing cancerous tumor cells found in patient blood samples.

Massachusetts General's BioMicroElectroMechanical Systems Resource Center has for the past few years been developing and testing a silicon-etched chip fitted with microscopic columns designed to sample and analyze circulating tumor cells (CTCs), malignant cells that carcinomas shed into the bloodstream. "The columns, or microposts, function as miniature test tubes where cells and chemicals can mix, adhere and undergo evaluation," Scientific American reported in March 2009.

J&J subsidiary Veridex is the only diagnostics company to have brought CTC technology to the U.S. market. The Food and Drug Administration (FDA) cleared the company's CellSearch System in January 2004 as a diagnostic tool for identifying and counting CTCs in a blood sample to help predict survival in patients with metastatic breast cancer. CellSearch was cleared as an aid in monitoring metastatic colorectal patients in November 2007 and in February 2008 got the go-ahead to aid in the monitoring of metastatic prostate cancer patients.

The new, jointly developed CTC platform is expected to take the work of both J&J and the hospital to a new level by isolating and exploring the biology of CTCs at the protein, RNA and DNA levels. Such cells are "extraordinarily rare and their detection presents a major challenge," according to a statement on the Massachusetts General Hospital Web site. If they can reliably be found and isolated, however, researchers believe they offer "a potential window into the real-time dynamics of a tumor's biology," according to the March 2009 Scientific American article.

Other efforts to develop a cancer-detecting blood test are also underway, including the Early Detection Initiative at Seattle's Fred Hutchinson Cancer Research Center. There, an interdisciplinary team of geneticists, computer scientists, oncologists and other researchers are developing tests that measure proteins in the blood and investigating how biomarkers can be used to identify cancer in its most formative stages. Whereas the CTC approach looks for cells, the Fred Hutchinson initiative looks at the proteins in a blood sample. The two methods are complementary and could someday be part of the same test.

"I envision blood tests and imaging technologies complementing each other—perhaps as a cost-effective panel of tests done in stages," geneticist and oncologist Amanda Paulovich, director of the Fred Hutchinson's Early Detection Initiative, told Scientific American in October. "A cheaper but less specific blood-screening test could be done first, followed by imaging. Alternatively, imaging could be used for initial screening, with follow-up blood testing to determine if a biopsy is necessary or if the disease is aggressive and needs to be treated."

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