Researchers have a range of protein-profiling methodologies at their disposal. In his presentation, William M. Gallagher, Ph.D., associate professor of cancer biology at University of California Davis, talked about how tissue microarrays and digital slide scanning technologies can greatly speed up biomarker development.
“We have actually stopped most of our omics-based discovery programs and shifted more of our efforts toward validation of our findings via high-throughput antibody-based assays on tissue microarrays—which, in a sense, can also be included within the proteomics sphere,” said Dr. Gallagher.
A core activity within Dr. Gallagher’s lab centers on the creation and use of tissue microarrays to provide a means for screening large numbers of clinical samples on a simultaneous basis. “This assay affords its own problems, namely surrounding downstream analysis via pathologist-based interpretation.”
“Accordingly, we have developed an automated approach to assist investigators to quantify expression of biomarkers that have been assessed via immunohistochemistry.” This approach, termed IHC-MARK, can discriminate tumor-specific expression of biomarkers at different subcellular levels, e.g., nuclear, cytoplasmic, and membranous. “We are currently in the process of commercializing this technology via our spin-out company, OncoMark.
“IHC-MARK has been road-tested so far on multiple tumor and marker types,” explained Dr. Gallagher, who is also CSO of OncoMark.
One of the key bottlenecks that Dr. Gallagher’s group initially faced was the difficulty in performing downstream validation of identified biomarkers of interest. “This required us to refocus our efforts on this crucial phase and develop new solutions such as the automated image-analysis approach to overcome these problems.
“Our findings suggest that such immunohistochemistry-based surrogates may provide more clinically applicable assays than complex gene-expression signatures. The result is a comprehensive biomarker development pathway that extends from discovery through validation on tissue microarrays, which is yielding clinically relevant biomarker panels for predicting outcome in breast cancer.”