March 14, 2013
We have partnered with investigators across the nation to obtain specimens and have used high-throughput profiling technology to comprehensively catalog a class of biomolecules called microRNAs (miRNAs) in blood samples from patients with prostate cancer and compared these to those from healthy individuals in the effort to identify new blood based biomarkers that may be useful in improving our ability to detect cancer early, help physicians accurately determine prognosis and monitor a patient's response to treatment. We have discovered multiple candidate biomarkers that are able to distinguish patients with cancer from healthy individuals. The approach we are developing has many key advantages over the standard methods used to discover biomarkers for cancer, as it is based on a new class of biomolecules (miRNAs) that are highly stable in the blood and are detectable by broad-spectrum, ultra-sensitive technologies. These technologies circumvent roadblocks that have hampered traditional protein-based biomarker discovery efforts and thus our miRNA approach could produce substantial advancements in cancer detection. To develop this technology, we sought to determine the physical state of cell-free miRNAs in human circulation. We have found that the majority of miRNAs circulating in healthy individuals are part of a soluble nucleic-acid/protein complex and contrary to expectations in the field, are not packaged into very small vesicles (exosomes). This information is useful in guiding the development of circulating miRNA-based diagnostics, as it has the potential to provide a basis for target enrichment to increase assay sensitivity.