May 5, 1996
Media Contact: Marc Kusintz
Phone: (410) 955-8665
A highly sensitive new technique for harvesting prostate cancer cells in blood may allow more rational use of anti-cancer drugs in advanced cases, say Johns Hopkins researchers who developed it.
The technique can detect a single prostate cancer cell among six million white cells in a sample of the patient's blood, says Alan Partin, M.D., Ph.D., associate professor in urology and senior author of the study. Partin is scheduled to present the findings of the study May 5 at the annual meeting of the American Urological Association in Orlando, Fla.
Scientists have harvested prostate cancer cells successfully in 12 patients so far, and a larger clinical trial will begin before summer, Partin says.
The ability to harvest these cells is important because men with advanced prostate cancer generally have had surgery or radiation therapy, and lack a source of cells that can be used for monitoring response to therapy, or for use in developing new gene-therapy vaccines for future treatment.
In addition, as new anti-cancer drugs are developed, the technique will let doctors test their effectiveness on the cells themselves, as well as monitor the success of the treatment by measuring the level of cancer cells in the blood.
"Being able to harvest and use a patient's own prostate cancer cells will help physicians to rationally decide which therapy is best suited for any individual person," says Partin. "And chosing the right treatment the first time should help to keep down the cost of caring for the patient."
To identify and separate the cells, the Hopkins team, led by Paul Ts'o, Ph.D., centrifuged--spun at high speed--the cells in a special liquid. Prostate cells, which have a known density, concentrated in the fluid at a specific level, permitting the researchers to harvest 75 to 85 percent of them, according to Partin.
The researchers also used special antibodies that recognize proteins on the surface of the white blood cells to collect and remove these cells from the mixture that contained prostate cancer cells. Using this technique, the team was able to obtain an enriched population of prostate cancer cells. The team demonstrated abnormal numbers of certain chromosomes that are only found in cancerous prostate cells.