Scientists say they have developed a highly effective new test for diagnosing prostate cancer, a potentially fatal disease that afflicts almost a million men around the world every year. Researchers say the test could dramatically reduce the number of costly and often unnecessary biopsies and improve patients' chances of survival.
The new prostate test identifies a series of 15 so-called biomarkers, traces of protein and other biological substances coursing through the bloodstream, that stimulate the production of auto antibodies.
Auto antibodies are produced by the body's immune system to fight the cancer and usually appear in the presence of disease.
Researchers from Oxford Gene Technology and its subsidiary, Sense Proteomic Limited in England, developed the biomarker test.
"Auto antibodies can occur many years before the occurrence of any clinical symptoms. So, the use of this type of technology as a sort of mass screening test holds a lot of potential," said said John Anson, Proteomic's vice president at Sense Proteomic.
An estimated 250,000 men die each year around the world from cancer of the prostate, a chestnut-shaped organ that's part of the male reproductive system that produces the secretions that contain sperm.
Currently, the only test for prostate cancer measures levels of a single protein called prostate specific antigen, or PSA, made by the immune system when cancer is present.
But experts say the PSA test is only accurate in detecting prostate cancer half of the time; PSA can be elevated due to other conditions, including a benign enlargement of the gland which is common in older men.
Researchers developed a micro-array, or panel of more than 900 proteins. A preliminary experiment involving 73 blood samples taken from men with prostate cancer and 60 cancer-free men showed the biomarker panel was 90 percent effective in detecting the disease.
Scientists say the next step is to test 1,700 blood samples against the proteins to detect auto-antibodies.
Some of the samples come from men with prostate cancer. The remainder of the samples are taken from men with benign enlargement of the prostate and healthy men.
Anson says scientists hope the test will spot men with aggressive prostate cancer at the earliest stages of the disease so they can be treated early, increasing their chances of survival.
The test also has the potential to identify men with indolent or less aggressive forms of prostate cancer. "Testing for prostate cancer really is to identify those individuals that have the aggressive form of the disease versus those that don't have the disease or the indolent form of the disease. The indolent form of the disease is not necessarily life-threatening," he said.
Researchers also say the microarray test could spare many men with elevated PSAs uncomfortable biopsies in which they have prostate tissue samples removed to look for cancer.