“There is a definite move to multiplexing on many more platforms,” explained Dr. Baldwin. “We offer services for microarray-based profiling of RNA, microRNA, DNA sequences and modifications, and proteins. Molecular diagnostics is still predominantly at a point where you only measure one thing at a time. Mostly, basic research has driven our demand for highly multiplexed assays. But some of that research is finally being translated into clinical applications that use the power of multiplexed analysis.”
Dr. Baldwin noted that there are now ways to barcode the samples. “That way you can multiplex many samples, as well as analytes, thus increasing the throughput. For molecular diagnostics—FDA has approved the first wave of multiplexed tests—there is no technical reason we can’t use multiplex technology, but we are still in the process of discovering what relevance tests have and how they inform clinical decision.”
In one application recently approved by the FDA, the Pathwork Diagnostics microarray tests expressed several thousand genes to determine the tissue of origin for a metastatic tumor. “This approach is familiar to genomics researchers—take a tissue sample, extract RNA, and put it on a microarray, match the gene-expression profile to reference sets, and find the pattern,” noted Dr. Baldwin.
“But pathologists can usually accomplish the same thing with histology and immunology tools. There is a big need for this technology, and we need to be doing more of this in the clinical setting, but it must offer clear advantages or enhance and expand current clinical practice.”
Many basic research projects are at the stage of consolidating gene-expression signatures from whole-genome data sets into focused multiplex panels. More formalized clinical trials will be the next step.
“A lot of people appreciate the power of multiplexing technology. Genotyping for functional and structural genomics and measurements of gene expression and activity for functional genomics, are all applications that have benefited. Now it’s time for us to turn to translational services,” remarked Dr. Baldwin. “And to do this well, you have to get the clinicians onboard early. Every test has to be justified, validated, and implemented with patient care in mind.”
At the CHI meeting, Dr. Baldwin observed that the rapid development of several genomics platforms for microRNA (miRNA) discovery and detection has created opportunities for translation to biomarker applications.
“Detection assays range from high-throughput single-target methods, to custom multiplex panels, to comprehensive microarrays, genomic tiling arrays, and next-generation sequencing,” he explained.
“Clearly, lots of people are working on microRNAs from basic mechanisms through biomarker utility to impact on disease development and therapies. This is what it’s all about.”