Wisconsin researchers develop more reliable prostate cancer test
A first-of-its-kind study has found that widespread cellular changes in otherwise normal tissue may be a “cancer signature” that could either support the decision for repeat biopsies or prevent unnecessary ones.
In a study published today by Neoplasia.com, Dr. David Jarrard and his research team at the University of Wisconsin Carbone Cancer Center compared prostate tissue from men with and without prostate cancer. The researchers looked at 385,000 areas of DNA and found 87 chromosomal differences between the tissues from men with prostate cancer and those without. The researchers then used several of these changes as a test in a follow-up clinical study.
“The findings suggest that normal-appearing tissues in peripheral areas of the prostate could actually show cellular changes and serve as a marker for cancer,” said Jarrard. “The work is important because patients with elevated PSA tests may have cancers that are not always found by needle biopsy.” Up to 30 percent of prostate cancers are not detected in an initial needle biopsy.
For patients with consistently high PSA levels who do not have cancer and may undergo repeated biopsies, testing cells from a negative biopsy for these markers would provide reassurance that more biopsies are not required. The paper also suggested that aggressive cancers leave a unique fingerprint in the normal prostate tissue, potentially allowing these dangerous cancers to be detected earlier.
To examine the clinical application of these findings, the research team looked at 50 normal-appearing prostate biopsy samples that included men with tumors and men with no evidence of cancer. This study, recently published by the Journal of Urology, used several of these markers to confirm the absence of cancer in patients with high PSA levels and negative biopsy results. They were able to do this with a 91% confidence rate.
“A test to reassure men that they don’t have cancer even with an elevated PSA level has the potential to save hundreds of thousands of men each year from having to undergo repeated biopsies” Jarrard says.
The next step would be to test this assay in larger groups of patients before making the test more widely available for patients with high PSA levels. Furthermore, if the molecular signature is detectable in the urine, doctors might be able to detect the cancer earlier and with a less-invasive urine sample.
“These findings of altered tissues associated with cancer are a unique way of looking at cancer diagnosis and treatment that could be adapted to other cancers.”
The studies were funded by the National Institutes of Health (No. 5R01CA097131).