Protein in prostate biopsies signals increased cancer risk

Researchers from Weill Cornell Medical College have shown that the presence of a particular protein in biopsied prostate tissue substantially increases the likelihood that cancer will develop in that organ. The discovery will likely help physicians decide how closely to monitor men potentially at risk for the cancer - among the most confusing and controversial dilemmas in health care.

Their findings, reported in the Journal of Clinical Oncology, are the first to quantify, in the setting of a clinical trial, the increased risk of prostate cancer development from the protein ERG.

Traditional means of determining risk of prostate cancer - blood tests for the protein prostate-specific antigen (PSA) and biopsies - do not always correlate well with the chances of dying from the disease. Decisions on what to do with the results of these tests can be unclear, leaving doctors and patients frustrated and unsure of how to proceed.

Researchers at Weill Cornell Medical College are looking at specific changes within prostate cells, from an initial biopsy, to determine which men have a higher risk of prostate cancer development and need repeat biopsies or other types of monitoring. This study starts to fill in the picture for about 10 percent of prostate biopsies.

Investigators found that 53 percent of men whose prostate biopsies showed expression of ERG protein developed invasive prostate cancer, compared to 35 percent of men whose biopsies were ERG-negative. All of the biopsies were classified as having high-grade prostatic intraepithelial neoplasia (HGPIN), which are lesions that may or may not morph into cancer.

The findings mean that potentially thousands of men a year - those with ERG-positive HGPIN biopsies - may benefit from increased surveillance and early treatment of prostate cancer, while those whose HGPIN biopsies come back ERG-negative may be able to avoid unnecessary future biopsies, says the study's senior investigator, Dr. Mark Rubin, the Homer T. Hirst Professor of Oncology in Pathology and professor of pathology and laboratory medicine.

"This study is the largest ever conducted that focuses on looking at HGPIN and ERG in a systematic way. We found that more than half of patients with these biomarkers go on to develop prostate cancer, and that is a significant finding which we now want to test in a prospective clinical trial," says Rubin, who is also director of the Institute for Precision Medicine at Weill Cornell and New York-Presbyterian Hospital and a professor of urology.

"What this study shows is that not all HGPIN is equal - that is, clinically significant," Rubin adds. "When confirmed in larger studies, testing for ERG in these precancerous lesions may change clinical practice in how men are evaluated with abnormal biopsies and may lead to earlier cancer detection."

Physicians today take a widely varying approach to monitoring patients who have an HGPIN-positive prostate biopsy, says study co-author Dr. Christopher Barbieri, a research fellow in the Department of Urology at Weill Cornell Medical College.