Hopkins researchers develop potential new screening test for prostate cancer

November 20, 2001

Scientists at Johns Hopkins have found that measuring the level of a chemical process linked to a genetic change associated with prostate cancer could greatly strengthen standard detection of early-stage curable disease. The report is published in the November 21 issue of the Journal of the National Cancer Institute.

In 1994, Johns Hopkins researchers found that a mutation in a gene that directs the formation of glutathione S-transferase (GSTP1) alters levels of an enzyme that detoxifies environmental carcinogens and protects against cancer. Changes in this gene lead to hypermethylation, now known to be the most common genetic error in prostate cancer. "Hyper"methylation (too much or abnormal methylation) is a biochemical process that inactivates the GSTP1 gene, shutting off its cancer-preventing properties, and is most often seen in early-stage prostate cancers and rarely in normal or benign prostate disease.

"A genetic marker such as GSTP1 that occurs mostly in early-stage prostate cancers may improve the way we diagnose cancer in the future and help us to catch it early," says David Sidransky, M.D., professor of otolaryngology, oncology and urology and director of the research.

In the current study, Hopkins scientists used a technique called methylation-specific PCR to examine tissue samples from 69 patients with early-stage prostate cancer and 31 patients with benign prostate disease. The researchers also evaluated prostatic intraepithelial neoplasia (PIN) lesions found in 28 of the 69 patients with early-stage disease. PIN lesions are thought to be early precursors of prostate cancer. High levels of GSTP1 methylation were detected in 63 of 69 (91.3 percent) early-stage cancers and in 15 of 28 PIN lesions (53.6 percent). Some GSTP1 methylation was found in nine of 31 samples (29 percent) of benign disease.

To test if GSTP1 methylation could be detected in small biopsy samples, the scientists tested biopsied prostate tissue from 21 patients with high PSA levels. Investigators correctly predicted a diagnosis of prostate cancer in 10 of 11 samples later found to be positive for cancer by pathology. They also correctly excluded a diagnosis of prostate cancer in all 10 patients with no evidence of cancer.

The researchers caution that these are early studies, and additional tests are necessary to verify the usefulness of the diagnostic technique.

Prostate cancer is the second leading cause of cancer death in men in the United States. Approximately 198,100 men were diagnosed last year and an additional 31,500 men died from the disease.

Participants in this study include Henning Usadel from Johns Hopkins; Carmen Jerónimo, Rui Henrique, Jorge Oliveira and Carlos Lopez from Instituto Portugu s de Oncologia de Francisco Genril-Centro Regional do Porto, Portugal; and William Nelson from Johns Hopkins.

Under a license agreement between the Johns Hopkins University and Virco, Ltd., Dr. Sidransky is entitled to a share of royalty received by the University on sales of products embodying the technology reported in this press release. The University and Dr. Sidransky own Virco stock, which is subject to certain restrictions under University policy. Dr. Sidransky is a paid consultant to Virco. The terms of this arrangement are being managed by the University in accordance with its conflict of interest policies.
Jerónimo, Carmen, et al., Quantitation of GSTP1 Methylation in Non-neoplastic Prostatic Tissue and Organ-Confined Prostate Adenocarcinoma. Journal of the National Cancer Institute, 2001, vol. 93, no. 22.

Related Web site:
Johns Hopkins Oncology Center: http://www.hopkinscancercenter.org

Media contact: Vanessa Wasta 410-955-1287, Email: wastava@jhmi.edu

Johns Hopkins Medical Institutions' news releases are available on an EMBARGOED basis on EurekAlert at http://www.eurekalert.org, Newswise at http://www.newswise.com and from the Office of Communications and Public Affairs' direct e-mail news release service. To enroll, call 410-955-4288 or send e-mail to bsimpkins@jhmi.edu

On a POST-EMBARGOED basis find them at http://www.hopkinsmedicine.org and Quadnet at http://www.quad-net.com

Johns Hopkins Medicine

Related Prostate Cancer Articles from Brightsurf:

Low risk of cancer spread on active surveillance for early prostate cancer
Men undergoing active surveillance for prostate cancer have very low rates - one percent or less - of cancer spread (metastases) or death from prostate cancer, according to a recent study published in the Journal of Urology®, an Official Journal of the American Urological Association (AUA).

ESMO 2020: Breast cancer drug set to transform prostate cancer treatment
A drug used to treat breast and ovarian cancer can extend the lives of some men with prostate cancer and should become a new standard treatment for the disease, concludes a major trial which is set to change clinical practice.

Major trial shows breast cancer drug can hit prostate cancer Achilles heel
A drug already licensed for the treatment of breast and ovarian cancers is more effective than targeted hormone therapy at keeping cancer in check in some men with advanced prostate cancer, a major clinical trial reports.

The Lancet: Prostate cancer study finds molecular imaging could transform management of patients with aggressive cancer
Results from a randomised controlled trial involving 300 prostate cancer patients find that a molecular imaging technique is more accurate than conventional medical imaging and recommends the scans be introduced into routine clinical practice.

Common genetic defect in prostate cancer inspires path to new anti-cancer drugs
Researchers found that, in prostate cancer, a mutation leading to the loss of one allele of a tumor suppressor gene known as PPP2R2A is enough to worsen a tumor caused by other mutations.

First prostate cancer therapy to target genes delays cancer progression
For the first time, prostate cancer has been treated based on the genetic makeup of the cancer, resulting in delayed disease progression, delayed time to pain progression, and potentially extending lives in patients with advanced, metastatic prostate cancer, reports a large phase 3 trial.

Men taking medications for enlarged prostate face delays in prostate cancer diagnosis
University of California San Diego School of Medicine researchers report that men treated with medications for benign prostatic hyperplasia (enlarged prostate) experienced a two-year delay in diagnosis of their prostate cancer and were twice as likely to have advanced disease upon diagnosis.

CNIO researchers confirm links between aggressive prostate cancer and hereditary breast cancer
The study has potential implications for families with members suffering from these types of tumours who are at an increased risk of developing cancer.

Distinguishing fatal prostate cancer from 'manageable' cancer now possible
Scientists at the University of York have found a way of distinguishing between fatal prostate cancer and manageable cancer, which could reduce unnecessary surgeries and radiotherapy.

Researchers find prostate cancer drug byproduct can fuel cancer cells
A genetic anomaly in certain men with prostate cancer may impact their response to common drugs used to treat the disease, according to new research at Cleveland Clinic.

Read More: Prostate Cancer News and Prostate Cancer Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.