An experimental biomarker test developed by researchers at the University of Michigan more accurately detects prostate cancer than any other screening method currently in use, according to a study published in the February 1 issue of Cancer Research, a journal of the American Association for Cancer Research.
The researchers say a simple urine test that screens for the presence of four different RNA molecules accurately identified 80 percent of patients in a study who were later found to have prostate cancer, and was 61 percent effective in ruling out disease in other study participants.
This is far more accurate than the PSA blood test currently in use worldwide, which can accurately detect prostate cancer in men with the disease but which also identifies many men with enlarged prostate glands who do not develop cancer, researchers say. Even the newer PCA3 test, which screens for a molecule specific to prostate cancer and which is now in use both in the U.S. and Europe is less precise, they say.
"Relative to what is out there, this is the best test so far," said the study's lead author, Arul Chinnaiyan, M.D., Ph.D., director of the Michigan Center for Translational Pathology at the University of Michigan.
He also says that this "first generation multiplex" biomarker test will likely be improved upon as researchers continue to uncover the molecular underpinnings of prostate cancer.
"We want to develop a test to allow physicians to predict whether their patients have prostate cancer that is so accurate a biopsy won't be needed to rule cancer out," Chinnaiyan said. "No test can do that now."
Chinnaiyan and the Michigan researchers developed the test based on their recent finding that gene fusions - pieces of chromosomes that trade places with each other, causing two genes to stick together - are common in prostate cancer, and that by overriding molecular switches that turn off excess growth, they may be the causative factor in some forms of the disease. In 2005 they identified a prostate-specific gene called TMPRSS2 which fuses with either ERG or ETV1, two genes known to be involved in several types of cancer. In 2007, they identified another five genes that fuse on to ERG or ETV1 to cause prostate cancer.
In the current study, researchers built upon the PCA3 test by screening for six additional biomarkers, including TMPRSS2:ERG as well as some molecules generally over-expressed in prostate cancer, and some which are over-expressed in specific cancer subtypes.
Researchers collected urine samples from 234 men with rising PSA levels before they underwent prostate biopsy at a University of Michigan urology clinic. Among this group, biopsy results confirmed a diagnosis of prostate cancer in 138 patients; 96 patients were cancer-free.
Correlating the urine biomarker test results with the biopsy data, researchers found that, in combination, four of the seven biomarkers were significant predictors of prostate cancer: GOLPH2, which is generally over-expressed in prostate cancer; SPINK1, over-expressed in a subset of these cancers; the PCA3 transcript expression; and TMPRSS2:ERG fusion status. Of the seven markers, only PCA3 had been previously reported as a diagnostic biomarker.
When tested as individual biomarkers, GOLPH2, PCA3, and SPINK1 each outperformed PSA, which had identified all of the men in the study as potentially positive for prostate cancer. "PSA was not predictive at all," Chinnaiyan said. "You might as well have flipped a coin."
The combination of the four biomarkers achieved a specificity and positive predictive value of greater than 75 percent, which they found to be five percent better than use of a PCA3 test alone, he says. Specificity is the probability that a test indicates a negative result if a person does not have a disease, and the positive predictive value is the proportion of patients with positive test results who are correctly diagnosed.
Chinnaiyan believes that any tests that are developed and widely tested would first be used to supplement a PSA blood screen.
The study was funded by the Early Detection Research Network, Department of Defense, the National Institutes of Health, the Prostate Cancer Foundation, and Gen-Probe Incorporated of San Diego. The gene fusion technology has been patented by the University of Michigan and licensed to Gen-Probe Inc, which is also developing the PCA3 screening test. Chinnaiyan is a paid consultant to Gen-Probe.
The mission of the American Association for Cancer Research is to prevent and cure cancer. Founded in 1907, AACR is the world's oldest and largest professional organization dedicated to advancing cancer research. The membership includes nearly 27,000 basic, translational, and clinical researchers; health care professionals; and cancer survivors and advocates in the United States and more than 70 other countries. AACR marshals the full spectrum of expertise from the cancer community to accelerate progress in the prevention, diagnosis and treatment of cancer through high-quality scientific and educational programs. It funds innovative, meritorious research grants. The AACR Annual Meeting attracts more than 17,000 participants who share the latest discoveries and developments in the field. Special Conferences throughout the year present novel data across a wide variety of topics in cancer research, treatment, and patient care. AACR publishes five major peer-reviewed journals: Cancer Research; Clinical Cancer Research; Molecular Cancer Therapeutics; Molecular Cancer Research; and Cancer Epidemiology, Biomarkers & Prevention. Its most recent publication and its sixth major journal, Cancer Prevention Research, is the only journal worldwide dedicated exclusively to cancer prevention, from preclinical research to clinical trials. The AACR also publishes CR, a magazine for cancer survivors, patient advocates, their families, physicians, and scientists. CR provides a forum for sharing essential, evidence-based information and perspectives on progress in cancer research, survivorship, and advocacy.
Staci Vernick Goldberg | EurekAlert!
Norovirus evades immune system by hiding out in rare gut cells
12.10.2017 | University of Pennsylvania School of Medicine
Flexible sensors can detect movement in GI tract
11.10.2017 | Massachusetts Institute of Technology
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
17.10.2017 | Life Sciences
17.10.2017 | Life Sciences
17.10.2017 | Earth Sciences