Testing for non-coding RNA molecules in urine may offer a way to detect prostate cancer that is more accurate and reliable than current methods using biomarkers such as PSA and PCA3.
This was the conclusion of a German study presented at the European Association of Urology Congress (EAU16) in Munich, Germany, March 11-15, 2016.
Friedemann Horn, a professor in the University of Leipzig and the Fraunhofer Institute for Cell Therapy and Immunology IZI, and Manfred Wirth, a professor in the University of Dresden - both in Germany - led the work.
Prof. Wirth says:
"Our work on RNAs [ribonucleic acid] is allowing us to design a completely new kind of prostate cancer test."
Current biomarker tests for prostate cancer measure levels of PSA (prostate-specific antigen) and PCA3 (prostate cancer gene 3), but they are not particularly accurate and can either miss many cancers or produce false positives.
The researchers behind the new study have identified a series of non-coding RNA molecules that could potentially be combined into a single urine test to detect prostate cancer.
They say their test could offer greater sensitivity and specificity than the current biomarker tests and thus make population screening much more viable.
A test with high sensitivity is good at ruling out disease when the result is negative, and a test with high specificity is good at ruling in disease when the result is positive.
Non-coding RNAs showed better specificity and sensitivity
Progress in genomic science is revealing that genetic programming in human beings and other higher organisms is far more intricate and complicated than we thought. It appears our bodies express a huge repertoire of previously overlooked molecules that orchestrate a hidden layer of genetic signals involved in health and disease.
- Other than skin cancer, prostate cancer is the most common cancer in American men
- About 1 man in 7 will be diagnosed with prostate cancer during his lifetime
- The average age at the time of diagnosis is about 66.
One group of these genetic molecules is non-coding RNA. RNAs are molecules that help to read and translate DNA (deoxyribonucleic acid) to make proteins - the workhorses of cells.
Until recently, it was thought that many RNAs that do not help make proteins - called non-coding RNAs - were simply "junk" and had no particular function.
Now, greater understanding of non-coding RNAs reveals they help control many biological processes, including the development and progression of cancer, and measuring them could offer a way to detect disease.
For their study, the researchers took 64 prostate cancer tissue samples obtained from biopsies and read 200 million sequences in genetic molecules from each sample. They found over 2,000 sequences that were significantly different in tumor samples than in healthy controls.
Some of these sequences were for non-coding RNAs that showed better specificity and sensitivity than established prostate markers.
The biomarkers were also found to be present in urine samples from cancer patients, and initial tests suggest they offer a precise way to detect the disease.
Combination of biomarkers will give better specificity
One of the non-coding RNAs - called tumor-associated proliferation-inducing RNA (TAPIR) - also showed significant promise in stopping cancer cell growth. However, the team says it is too soon to say whether this result will prove to be clinically useful.
The team is now developing a highly specific and sensitive urine test for the early diagnosis of prostate cancer. The test will use a combination of biomarkers rather than just a single one.
Prof. Wirth says the work is still in the early stages, but results look promising. It offers a new approach to diagnosing prostate cancer and arises from applying basic science to a clinical problem. He concludes:
"Given that our initial results show a high specificity for prostate cancer in urine tests, the prospects are good that we will be able to translate this into a better test for prostate cancer. We have several good candidate biomarkers, however we are aiming to design a test which utilizes a combination of biomarkers. This will give significantly better specificity than existing tests."
The study is part of a project called RIBOLUTION (RIBOnucleic acid-based diagnostic soLUTIONs) - funded by the Fraunhofer Future Foundation - that aims to identify new RNA biomarkers and to develop novel diagnostic tests.
The American Cancer Society estimate that in 2016, about 180,890 American men will be diagnosed with prostate cancer, and about 26,120 will die of the disease.
Meanwhile, Medical News Today recently learned that the survival time for men with metastatic prostate cancer may depend on which part of the body the disease spreads to.