Cancer metastases (spreading from the initial cancer tumor to other parts of the body) account for the majority of cancer-related deaths because of poor responses to anti-cancer therapies.
Researchers at Weill Cornell Medical College, in collaboration with engineers from Cornell University in Ithaca, NY, have created a new device that searches the blood for living, circulating tumor cells. The device allows researchers to capture and molecularly characterize circulating tumor cells (CTCs) isolated from castrate-resistant prostate cancer patients (CRPC) receiving taxane chemotherapy. This new device will allow physicians to monitor drug response at the cellular level, which will potentially allow physicians to tailor prostate cancer treatments to an individual patient. The device is the first functional assay of a microtubule-targeting agent on living circulating tumor cells microfluidically extracted from patient blood.
Circulating tumor cells are prostate cancer cells which have escaped from prostate tumors (from the prostate, bone, or other areas) and are circulating in blood. The FDA has cleared a specific type of test to enumerate (or count) the number of these cells in a tube of blood, called the CellSearch test. The advantage of this test is that it has been well studied at many centers and has been validated to yield prognostic information. However, this test is not very sensitive; men with metastatic prostate cancer may have no detectable cells. In addition, this test is not specific to prostate cancer – the same test also picks up different cells (it is also cleared for breast and colon cancer).
The New Device
The collaborating researchers at Weill Cornell and Cornell University developed a new test called the “Geometrically Enhanced Differential Immunocapture” device. The device has been optimized based upon flow and size characteristics of prostate cancer cells. Importantly, the device uses additional technology developed at Weill Cornell, a monoclonal antibody against Prostate Specific Membrane Antigen (PSMA). The anti-PSMA antibody called J591, developed by Dr. Neil Bander in the Weill Cornell Department of Urology, specifically recognizes the PSMA protein which is present on the surface of virtually all prostate cancer cells. The combined technology has allowed Weill Cornell researchers to collect and analyze more prostate cancer cells than the standard device.
In addition to prognostic information, it is hoped that the capture and analysis of CTCs may serve as a type of “liquid biopsy” to allow researchers to gain information about a patient’s tumor. Initial work has led to promising results in the ability to predict future responses to chemotherapy based upon a blood test prior to the drug or after only 1 dose.
The authors write, “these measurements constitute the first functional assays of drug-target engagement in living circulating tumor cells and therefore have the potential to enable longitudinal monitoring of target response and inform the development of new anticancer agents.”
Click here to read the published research paper.