MicroRNA Analysis: Is It Ready for Prime Time?

Since their discovery, microRNAs (miRNAs)20 have shown great promise in a wide array of clinical applications. In some cases, the use of miRNAs as new diagnostic markers might help answer diagnostic dilemmas that gene expression analyses or other types of analyses have not been able to satisfactorily address. In other instances, it is easy to perceive certain miRNAs as targets for novel therapies that downregulate an entire pathway via the targeting of a single miRNA. When and if this concept will come to fruition remain unclear. Scientists agree that this field of biology is exciting, offers much promise, and has numerous advantages, compared with experiences with other biomolecules. In this Q&A, 5 individuals with extensive miRNA experience share their vision for where the miRNA field is heading and whether we, in the clinical laboratory, will experience its implications soon. What are the most important characteristics of miRNAs that increase their potential as novel diagnostic or therapeutic targets? George Calin: One important characteristic of miRNAs that makes them an exciting potential biomarker for diagnosis and/or a target for therapy is the fact that specific miRNAs target multiple components from the same pathway. For example, the miR-15a/16–1 cluster targets genes from the apoptotic pathway: BCL2 21 (B-cell CLL/lymphoma 2) and MCL1 [myeloid cell leukemia sequence 1 ( BCL2 -related)]. Any given miRNA can regulate numerous genes, and each gene can be regulated by different miRNAs. Pierre Cordelier: In cancer research, miRNAs can differentiate normal from cancerous tissues and, more importantly, can discriminate different subtypes of cancer. The high stability of miRNAs in tissues and fluids is another key advantage that increases their potential as diagnostic markers over messenger RNA (mRNA). In addition, they can be quantified in very low amounts of material and in highly degraded samples. This is of prime importance …