Soon scientists will be able to detect a single cancer cell among the billions of cells that circulate in the human bloodstream. The method could detect whether the therapy has worked or even show which therapy would work best. The test depends on circulating tumor cells (CTCs) or cancer cells that have detached from the main tumor and are travelling to other parts of the body.
Earlier in 2007, the scientists at Massachusetts General Hospital developed a “microfluidic chip,” called CellSearch. It could count the number of stray cancer cells, but that test did not allow scientists to trap whole cells and analyze them. This Monday however Mass General came up with an agreement with Veridex LLC (part of Johnson & Johnson) to work on a newer version of the test.
This test would need a very small amount of blood – only about two teaspoons. The microchip contains tens of thousands of tiny posts covered with antibodies designed to stick to tumor cells. As blood passes over the chip, tumor cells separate from the pack and adhere to the posts.
Nicholas Dracopoli, vice president of Ortho Biotech Oncology Research and Development (ORD), a unit of Johnson & Johnson said, “The new technology allows us to not just count them but to understand the molecular changes that lead to the disease progression that is occurring in the cells…And that will then allow us to do sophisticated molecular analysis of those isolated cells so that we can then look and see if there are therapies that are optimally suited to a patient with those particular abnormalities.”
Lead CTC chip researcher Mehmet Toner who is director of the BioMicroElectroMechanical Systems Resource Center in Massachusetts General’s Center for Engineering in Medicine added, “This collaboration is an opportunity to apply our past learning to the advancement of a platform that will ultimately benefit patients with cancer.”
“This new technology has the potential to facilitate an easy-to-administer, non-invasive blood test that would allow us to count tumor cells, and to characterize the biology of the cells…Harnessing the information contained in these cells in an in-vitro clinical setting could enable tools to help select treatment and monitor how patients are responding,” said Robert McCormack, Veridex’s head of technology innovation and strategy.
Another angle to this discovery could be early detection of the cancer, prediction of recurrence and assessment of prognosis. Dr. Massimo Cristofanilli, professor and chairman of medical oncology at Fox Chase Cancer Center in Philadelphia said, “There has been speculation that these ‘stray’ cells are the ones that are responsible for the spreading of the disease… Simple enumeration tells us that this patient has a worse prognosis . . . Now the question is, what other information we can gather, if we are able to capture these cells? For example, could we do gene analysis profiling and can we get information for the best treatment?” At present biopsy is one of the only but painful and invasive ways to detect the cancer’s characteristics. Cristofanilli, who is not involved in developing the test said, “Many people consider [the new blood test to be] a ‘liquid biopsy,’ so that eventually we can access cancer cells that are representative of the tumor without performing an invasive biopsy.”
The actual refined and ready to use test would take years to come into the market say researchers. Dr. Jay Brooks, chairman of haematology/oncology at Ochsner Health System in Baton Rouge said, “They may be able to detect small amounts of cancer cells but we don’t know the significance of that. We may be detecting things that don’t have clinical significance.” Four major cancer centers – Mass General, Memorial Sloan-Kettering Cancer Center in New York City, the University of Texas’ M.D. Anderson Cancer Center in Houston, and the Dana-Farber Cancer Institute in Boston will begin studies using the new test this year. Cristofanilli added that the test would need to be developed “along with the process of new drug development and new targeted therapies so we can better use the information with a clinical purpose.”
The American Cancer Society said the new research is exciting but caution should be exerted before putting up hopes. Dr. Len Lichtenfeld, the group’s deputy chief medical officer said, “Researchers have been working on this and similar technologies for some time, and others have predicted a day when we will be able to diagnose cancers before they are otherwise visible by current techniques…It is appropriate to view announcements such as the one today with enthusiasm, but recognize that we must temper that excitement with the realization that there is still much research to be done to determine the true impact of this test on the treatment of patients with cancer.”
The US Food and Drug Administration had approved the earlier generation technology for use in detecting cancer cells in the blood of patients with metastatic, or advanced stage, breast, prostate and colorectal cancer. Dracopoli said it could be three to five years before FDA clinical trials produce results that show the technique works toward detecting and treating a broader range of cancers.
By Dr Ananya Mandal