Nanodevice, fluid capacity could be gauges of prostate cancer
The first question after a diagnosis of prostate cancer: Is the cancer slow-growing or fast-growing?
A slow-growing prostate cancer can simply be monitored, enabling patients to avoid potential side effects of treatment for as long as possible. A fast-growing cancer demands immediate attention, regardless of the risk of erectile dysfunction and urinary control issues.
The conundrum: There's often no reliable way to determine the difference without invasive measures.
Researchers in City of Hope’s Division of Urology and Urologic Oncology, however, are rapidly closing in on new ways to do just that.
"One way to approach this question is to look at a patient specimen – either a needle biopsy, a urine sample or some fluid from the prostate – for cancer cells and biomarkers like changes in the DNA that distinguish cancer cells from normal cells," said Steven Smith, Ph.D., a professor in the Division of Urology and Urologic Oncology. "Most of the biomarkers in use today originate in the cancer. However, we're looking at biomarkers that do not originate within the cancer cells themselves, but are a consequence of the cancer or a response to its presence."
Not only are their methods noninvasive, but two recently published studies show just how much promise their approaches may have.
In one paper, published June 6 in PLos One, lead author Elizabeth Singer, Ph.D., and her colleagues report that a nanodevice can detect – and bind to – biomarkers induced in cells surrounding the prostate cancer tumors.
The device is actually a Y-shaped DNA molecule, containing fluorescent dye, with proteins attached to it. The proteins home in on enzymes released by the body in the fight against cancer, and the dye makes the cancer tissue glow under certain light. Earlier tests had shown that the molecule was drawn to cancer tissue. The new paper establishes that the nanodevice can distinguish between a noncancerous condition known as BPH, or benign prostatic hyperplasia, and cancer.
"The results suggest that the body’s response to benign growth is very different from its response to cancer – and that looking for the effect of the cancer on the gland can be useful in diagnosis," said Smith, director of the lab in which Singer works.
The second study expands on the premise that cancer affects the body differently than does noncancerous conditions. In findings published online May 13 in the Journal of Urology, another team of researchers showed that prostate fluid can be used to find aggressive cancers in patients who have been misclassified as low risk by standard clinical tests.
Already City of Hope researchers had found that biomarkers within prostatic secretions could help determine whether men with prostate cancer are good candidates for watchful waiting. The new study focused on a broader measure – the volume of fluid.
"Like most glands in the body, the prostate produces a fluid and, as one might expect, when cancer takes over the gland, its ability to produce fluid is impaired," Smith said. "Glands that contain significant amounts of cancer yield lower amounts of fluid. Consequently the volume of the fluid that can be collected is a biomarker of cancer."
This secretion capacity test – which essentially assesses how well the gland functions – could be used to find aggressive cancers in patients who have been misclassified as low risk by standard clinical tests, the researchers concluded.
The Journal of Urology study was authored by Christopher Whelan, M.D., Mark Kawachi, M.D., David D. Smith, Ph.D., Jennifer Linehan, M.D., Gail Babilonia, B.S., Rosa Mejia, Timothy Wilson, M.D., the Pauline & Martin Collins Family Chair in Urology, and Steven Smith, all of City of Hope.
The PLoS One study was authored by Singer, Linehan, Babilonia, S. Ashraf Imam, Ph.D., David Smith, Sofia Loera, Wilson and Steven Smith.
Together, the papers take researchers, doctors – and patients – closer to a less-invasive, more conclusive analysis of their prostate cancer.