Researchers at Sanford–Burnham Medical Research Institute (FL, USA) have identified a set of RNA molecules observable in tissue and urine samples of prostate cancer patients, but not in patients without the cancer. The study is a promising step on the route to developing a more sensitive and specific noninvasive test for prostate cancer than those currently in use. The implementation of such a device could potentially reduce the number of unnecessary prostate biopsies, leading to reduced treatment related morbidity.
Most men with prostate cancer have a nonaggressive disease, which can be treated with conservative therapy or surveillance. Therefore the clinical challenge is not only how to identify those with prostate cancer, but also how to differentiate between those that would benefit from aggressive treatments, such as surgery, and those who would not.
Currently, prostate cancer is mainly detected and monitored by testing for high concentrations of Prostate-Specific Antigen (PSA) in blood samples. If PSA levels are high, a biopsy is usually the next port of call to confirm the presence of cancer, and its nature; slow growing or aggressive.
The current approach, however, is flawed, as elevated PSA levels can often be detected without the presence of cancer. Vipul Patel, Medical Director of the Global Robotics Institute (FL, USA) stated, “Only 25 percent of men with raised PSA levels that have a biopsy actually have prostate cancer. Prostate cancer needs to be screened for; we just need to find a better marker.” Moreover, elevated PSA levels shed no light on whether the cancer is lethal or less aggressive; “while elevated PSA can be an alert to a lethal cancer, it can also detect less aggressive cancers that may never do any harm,” Patel added.
Researchers now believe they have identified a family of long noncoding RNA (IncRNA) molecules that could potentially serve as better prognostic markers for prostate cancer. Ranjan Perera, from Sanford–Burnham (FL, USA) stated, “we have identified a set of lncRNAs that appear to have an important role in prostate cancer diagnostics.”
IncRNAs were initially believed to be nonfunctional noise in the genome, however, it is now thought that they regulate normal cellular development and contribute to a range of diseases, including cancer.
This research consisted of profiling the IncRNAs in three distinct groups: human prostate cancer cell lines and normal prostate epithelial cells; prostate adenocarcinoma tissue samples and matched normal tissue samples; urine samples from patients with prostate cancer or benign prostate hypoplasia; and healthy individuals. Researchers found that in all three groups IcnRNAs were raised in prostate cancer patient samples, but not in patients with benign prostate hypoplasia or healthy individuals. Perera explained, “The findings advance our understanding of the role of lncRNAs in cancer biology and, importantly, broaden the opportunity to use lncRNAs as biomarkers to detect prostate cancer.”
Prostate cancer is the second most common type of cancer in American men and is the second highest cause of cancer death in men (in the USA). Patel concluded, “there is a tremendous unmet clinical need for better non-invasive screening tools for early detection of prostate cancer to reduce the overtreatment and morbidity of this disease.” Patel envisages that these findings “represent a promising approach to meet this demand.”
Sources: Researchers Find RNA Molecules in Urine and Tissue That Detect Prostate Cancer; Lee B, Mazar J, Aftab MN, et al. Long noncoding RNAs as putative biomarkers for prostate cancer detection, J. Mol. Diagn. 16(6), 615–626 (2014).