A test that studies suggest will do a better job of diagnosing prostate cancer and give doctors an idea of how aggressive a tumor they are treating is coming into use.
Developed by researchers at the University of Michigan Health System, the Mi-Prostate Score test detects three separate biomarkers associated with prostate cancer in urine samples from men.
The current standard prostate cancer screening test looks for one biomarker, the prostate-specific antigen, or PSA, in blood samples.
The MiPS test was developed in part to address the roughly 1 million men a year who are initially diagnosed with prostate cancer, often as a result of an elevated PSA test result, but who are found not to have cancer during a subsequent prostate biopsy.
In addition, although an elevated PSA test result indicates prostate enlargement, that enlarged tissue is not necessarily cancerous.
"Many more men have elevated PSA than actually have cancer, but it can be difficult to determine this without biopsy," said Scott Tomlins, assistant professor of pathology and urology at the University of Michigan. Tomlins developed the MiPS in collaboration with Arul Chinnaiyan, the S.P. Hicks Endowed Professor of Pathology and Professor of Pathology and Urology at the University of Michigan Medical School.
The MiPS test in based on a 2005 discovery by Chinnaiyan's lab of a genetic anomaly that can be detected in about half of the men with prostate cancer. In the defect a pair of genes, known as T2 and ERG, switch places on a chromosome and fuse together.
The University of Michigan holds a patent on the detection of gene fusion in prostate cancer that lists Chinnaiyan and Tomlins as co-inventors.
In addition, the use of the technology has been licensed to Hologic, a company based in Bedford, Mass., that develops diagnostic and medical imaging systems. Chinnaiyan has been a consultant to Hologic.
MiPS not only tests for PSA and the T2:ERG fusion marker but also a third biomarker, PCA3.
The PCA3 gene is only found in prostate tissue and is overexpressed by cancerous prostate tissue.
Chinnaiyan and Tomlins say the test also predicts risk for having an aggressive tumor, helping doctors and patients make decisions about whether to wait and monitor test levels or undergo an immediate biopsy.
"This combination test is not designed to say definitively at diagnosis whether a man has aggressive prostate cancer, but it can provide a more accurate estimate of the likelihood of having cancer and the likelihood of that cancer being aggressive," Tomlins said.
For more information on the MiPS test, which requires a request from a doctor, is available by calling the University of Michigan's MLabs, toll free, at (800) 862-7284.