TUESDAY, Sept. 28, 2010 (HealthDay News) -- A new blood test to spot a cluster of specific proteins may indicate the presence of prostate cancer more accurately and earlier than is now possible, new research suggests.
The test, which has thus far only been assessed in a pilot study, is 90 percent accurate and returned fewer false-positive results than the prostate specific antigen (PSA) test, which is the current clinical standard, the researchers added.
Representatives of the British company that developed the test, Oxford Gene Technology in Oxford, presented the findings Tuesday at the International Conference on Molecular Diagnostics in Cancer Therapeutic Development in Denver, hosted by the American Association for Cancer Research.
The test looks for auto-antibodies for cancer, similar to the auto-antibodies associated with autoimmune diseases such as type 1 diabetes, rheumatoid arthritis and lupus.
"These are antibodies against our own proteins," explained John Anson, Oxford's vice president of biomarker discovery. "We're trying to look for antibodies generated in the early stages of cancer. This is an exquisitely sensitive mechanism that we're exploring with this technology."
Such a test generates some excitement not only because it could theoretically detect tumors earlier, when they are more treatable, but auto-antibodies can be "easily detected in blood serum. It's not an invasive technique. It's a simple blood test," Anson noted.
The researchers came up with groups of up to 15 biomarkers that were present in prostate cancer samples and not present in men without prostate cancer. The test also was able to differentiate actual prostate cancer from a more benign condition.
Because a patent is currently pending, Anson would not list the proteins included in the test.
"We are going on to a much more exhaustive follow-on study. At the moment, we are taking over 1,800 samples, which includes 1,200 controls with a whole range of 'interfering diseases' that men of 50-plus are prone to and are running a very large analytical validation study," Anson said.
That analysis is due to be completed early next year, at which point Oxford is "going to be seeking partnership to develop the test further," Anson said.
He also expressed hope that the technology could one day be applied to other diseases, including lupus, on which there is some preliminary data.
Anson predicted that, if further trials go well, the test could be available commercially in 10 to 15 years.
Researchers have been on the hunt for a better screening test for prostate cancer, given the unreliability of the current standard. Because the PSA test generates so many false-positives, many men end up getting surgery or radiation that they simply don't need.
"The current PSA test has a great sensitivity, of over 90 percent, but poor specificity, so there are a lot of false-positives," Anson said. "A lot of men are going on for unnecessary diagnostic procedures such as needle biopsies and perhaps radical prostatectomies that aren't required."
The field of biomarkers is intended to further the growing area of personalized medicine, where drugs and treatments are tailored to the specific characteristics of a person's cancer.
However, Dr. Gordon B. Mills, program chair of the cancer meeting and chair of the department of systems biology at the University of Texas M.D. Anderson Cancer Center in Houston, said "those drugs are not going to be very useful unless at the same time we are able to identify patients likely to benefit from them."
According to American Cancer Society estimates, about 218,000 cases of prostate cancer will be diagnosed in the country in 2010, and there will be approximately 32,050 deaths.
Prostate cancer is the most common type of cancer found in American men, other than skin cancer. One man in six will get prostate cancer during his lifetime, and one in 36 will die of the disease. More than 2 million men in the United States who have had prostate cancer are still alive today. The death rate for the disease is going down, and it's being found earlier, the cancer society says.
More information
The U.S. National Cancer Institute has more on prostate cancer.
