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Page 1 of 12  Could the future of prostate cancer encompass a vaccine against killer disease and a urine test that’s even more accurate to pinpoint a tumor than present-day methods?
That’s exactly what researchers at the University of Michigan and University of Southern California hope.
First, an experimental test developed at the University of Michigan more accurately detects prostate cancer than any other screening method currently in use. In fact, the simple urine test 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 others, according to the latest Cancer Research.
The test is far more accurate than the PSA blood test, which can accurately detect prostate cancer in men but also identify many men with enlarged prostate glands who do not develop cancer. In other words, an “abnormal” reading on a PSA test does not necessarily mean you have prostate cancer, and a “normal” reading doesn’t mean you don’t.
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.
No more biopsies? The test focuses on the presence in the urine of four different RNA molecules that doctors believe are present when a man has prostate cancer, says Dr. Arul Chinnaiyan, the study’s lead author and a University of Michigan pathology director. He adds that the “first generation” 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.
However, more study is needed before such a test can hit the market. 'Lifelong protection'
In another apparent breakthrough, University of Southern California scientists have developed a vaccine that thwarted the growth of early prostate cancer in 90 percent of the young mice genetically predestinated to develop the disease. Whether the test will do the same in men with rising PSAs is the big question for future research that may take several years, scientists say in Cancer Research.
“By early vaccination, we have basically given these mice life-long protection against a disease they were destined to have,” says W. Martin Kast, the lead researcher at USC’s Norris Comprehensive Cancer Center. “This has never been done before and, with further research, could represent a paradigm shift in the management of human prostate cancer.”
Now, some men with rising PSA levels but no other signs of cancer are advised to engage in “watchful waiting”—no treatment until signs of the cancer appear. But Kast poses this question, “What if instead of a watchful wait, we vaccinate? That could change the course of the disease.”
Vaccines now in testing are designed to treat men whose cancers of all types are advanced and unresponsive to therapy. So far, results have offered limited benefit, but Kast targets the precancerous state before cancer has developed.
The vaccine mounts an immune response against a protein that is screwed up in about one-third of early-stage prostate cancers, and gets even wackier as the cancer grows. The vaccine given to 18 of 20 young mice alerted the immune system, while a booster shot—ironically made from a horse virus—helped the rodents avoid advanced prostate cancer.
The critters had all developed very small tumors that did not progress, Kast says.
“Confronting the immune system in two different ways forces it to mount a strong response,” Kast says. “There were tiny nodules of prostate cancer in the mice that were surrounded by an army of immune system cells. The vaccination turned the cancer into a chronic, manageable disease.”
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