April 27, 1995
Media Contact: Marc Kusintz
Phone: (410) 955-8665
Researchers at The Johns Hopkins Medical Institutions and Matritech Inc. (Cambridge, Mass.) have developed an antibody that may offer a new non-surgical means of detecting and fighting prostate cancer, according to Alan Partin, M.D., Ph.D., a research fellow in the Department of Urology.
"A serum test using an antibody such as this might help men avoid the unnecessary and costly prostate biopsies that are caused by false positive results of PSA tests," says Partin. PSA (prostate specific antigen) is a protein made by the prostate gland. A rise in PSA levels may reflect either benign prostate hyperplasia or cancer.
"The new antibody also could be used to specifically target cancer cells with anti-cancer drugs," Partin says.
In laboratory studies, the antibody reacted with a protein called PC-1 in the nuclei of cancerous cells from 16 of 17 surgically removed prostate cancer specimens, says Partin, who presented the findings of his team's work at the annual meeting of the American Urology Association in Las Vegas, Nevada, on April 24.
"This antibody also holds great promise for helping doctors with cases of prostate cancer that are difficult to diagnose.
"Sometimes there is not enough tissue on the microscope slide, or the tissue has been damaged during handling, or doesn't look like typical prostate cancer cells," says Partin. "A test based on this antibody should make it easier to use such tissue to make accurate diagnoses."
Partin reports that the antibody also reacted with some cells from the prostate called intraepithelial neoplasia (PIN) cells, which may represent precancerous cells. In addition, the antibody reacted with nuclei from three of 18 benign prostate hyperplasia (BPH) specimens, a non-cancerous enlargement of the prostate; and with some adjacent, but non-cancerous cells in three of 18 tissue specimens.
"This antibody may offer an advantage over existing prostate cancer tissue diagnostic products because it identifies nuclei from cancerous cells as well as precancerous conditions in biopsy specimens," says Jonathan Epstein, M.D., professor of pathology at Johns Hopkins and a collaborator on the study.
PC-1 is one of many nuclear matrix proteins (NMP) that together make up the "skeleton" of the nucleus, which holds the chromosomes. The nuclear matrix makes up the internal framework of the nucleus, supporting it and providing its shape. In addition, it helps to organize the DNA inside the nucleus so that genes are readily accessible when the cell needs to translate the DNA blueprint into active proteins.
Johns Hopkins has given Matritech exclusive worldwide license to patent rights covering PC-1 and other NMPs specific to prostate cancer. The company is now using the technology to develop a blood test for men being tested for prostate cancer, and plans to start clinical trials of the test by late 1995 or early 1996.
Hopkins researchers led by Partin and Donald Coffey, Ph.D., director of research at the Department of Urology, and Robert H. Getzenberg, Ph.D., first reported their findings on PC-1 in the February 1993 issue of Cancer Research.
Prostate cancer is the second-leading cause of cancer death in men. According to the American Cancer Society, there were approximately 200,000 new cases of prostate cancer diagnosed in the United States in 1993 and approximately 38,000 men died of this disease.
Coffey and Partin, The Johns Hopkins University, and the other investigators are entitled to royalty derived from Matritech's sale of products related to the research described in this press release. The terms of this arrangement have been reviewed and approved by The Johns Hopkins University in accordance with its conflict-of-interest policies.