Genomic technologies enabling relatively simple, rapid, and costeffective high-throughput testing of RNA-based multiplexed signatures in blood samples would greatly facilitate wide-scale adoption of molecular diagnostic tests in clinical medicine. Tests like CardioDx’ Corus CAD and CAREDx’ Allomap represent the first generation of products designed to improve diagnosis, predict therapeutic response, monitor drug responses in patients, and determine disease prognosis from a simple blood draw. This emerging class of tests known as IVDMIA tests is demonstrating value in clinical applications, and many researchers are developing assays with these methods.
One group of researchers, Shi et al., recently reported the development of blood-based, three-gene signatures for the noninvasive detection of early human hepatocellular carcinoma. These scientists used comprehensive gene expression profiling of purified RNA of peripheral blood mononuclear cells (PBMCs). Gene signatureswere developed through bioinformatics-driven approaches, and their diagnostic value was evaluated by custom-designed, quantitative, multiplex PCR assays.
But several factors including the technical complexity of current testing platforms, the high cost of materials and labor to perform them, and the limited availability of validated tests limit wide clinical use of RNA-based expression signatures. Other limitations include the need for RNA stabilization by freezing or by addition of a chemical denaturant that inactivates RNases. These chemical denaturants inhibit downstream amplification and assay methods.
For the rest of the story, click here.