Researchers Announce Plans to Develop Test That Detects Circulating Tumor Cells
By Brenda Goodman
WebMD Health News
Reviewed by Louise Chang, MD
Jan. 3, 2011 -- Researchers have announced plans to develop a blood test that can detect a cancer cell that has been shed from a tumor.
The new test, which will be developed through a $30 million, five-year partnership between Johnson & Johnson and researchers at Massachusetts General Hospital, detects circulating tumor cells, or CTCs, which escape from solid tumors and travel through the blood to take root at new sites around the body.
In a separate effort, four cancer centers -- Massachusetts General Hospital and Dana-Farber Cancer Center, both in Boston, Memorial Sloan Kettering in New York City, and MD Anderson Cancer Center in Houston -- will start studying the test later this year. That effort has been backed by a $15 million grant from the Stand Up to Cancer telethon.
"These are the cells that continue to seed other sites in the body," says Massimo Cristofanilli, MD, chairman of medical oncology at Fox Chase Cancer Center in Philadelphia. "These are the cells responsible for metastasizing of cancer, which is why most patients ultimately die of the disease."
Cristofanilli thinks the test, which amounts to a "liquid biopsy," may not only be more convenient than taking tissue samples to see cancer cells, but may ultimately provide doctors with better information about the aggressiveness of a given cancer and how well efforts to treat it are working.
"We've been taking tissue biopsies for decades but we still haven't made much progress against cancer," Cristofanilli says. "This suggests that the information in the tumor may not be that valuable. It may be these cells that tell us more."
New Technology to Isolate CTCs
An earlier version of a test to detect CTCs, called CellSearch, was first approved by the FDA in 2004 to help doctors monitor patients with metastatic breast cancer. CellSearch is able to count cells, but it can't capture them, which allows doctors to see if they are responding to chemotherapy or radiation.
In 2007, researchers at Massachusetts General Hospital published a paper in the journal Nature announcing that they had developed new technology to isolate and catch whole CTCs on a microchip covered with 78,000 microposts. The tiny posts were coated with antibodies that bind to cancer cells, and when blood is forced across the chip, the posts comb cancer cells out of the plasma and hold them for analysis. In the trial, the microchip successfully captured CTC cells in nearly all patients with lung, breast, prostate, pancreatic, and colon cancer.
Right now, the tests are expensive. Each chip costs about $500. Researchers hope the new partnership will make the technology cheaper and easier to use.
Initially, doctors hope to use information from the new test to help determine the best treatment for individual patients and then to quickly follow how well those treatments are working.
"These are incredibly rare cells," says Daniel Haber, MD, PhD, director of the Cancer Center at Massachusetts General Hospital in Boston and one of the inventors of the new test. "Once you find them, you can count them. You can also test them for markers to see if they're responding to treatment. It really is a window into a cancer in real time without having to go in and biopsy the cancer."
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SOURCES: Massimo Cristofanilli, MD, chairman of medical oncology at Fox Chase Cancer Center, Philadelphia.Daniel Haber, MD, PhD, director, Cancer Center, Massachusetts General Hospital, Boston.News release, Massachusetts General Hospital.Alix-Panabières, C. Clinical Cancer Research, Dec. 15, 2010.Nagrath, S. Nature, Dec. 20, 2007.
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