Current pathology approaches are largely based on the 19th century paradigm of sectioning tissue, applying the section to a glass slide, and staining it with various dyes for examination under a light microscope. The continued appeal of this approach has been its ability to show the shape and morphology of the tissue, which provides important information about the disease and diagnosis. However, this “classic” paradigm is laborious and ill suited when there is a need to identify multiple genes and proteins in a single section of a tumor or other diseased tissue. This multiplex capability is especially needed when profiling tumors to predict response to newer targeted therapies that impact numerous genes and proteins in parallel. 20/20’s patented Layered Peptide Arrays (LPA), unlike the classical techniques now in use, yields digital, numerical values from multiple genes or proteins while integrating this information with the shape and morphology of the tissue. Thus our technology marries the visual appeal of classical pathology with the throughput required of 21st century genomics and proteomics. It is the first technology that provides both the morphological advantages of immunohistochemistry (IHC) with the high-throughput and ease of use of microarrays. Importantly, as shown in the literature, our technology can be used for analysis of both fixed and frozen tissue and for whole sections, tissue microarrays, and even hair follicles. The ability to identify proteins in formalin-fixed, paraffin-embedded tissue is a major accomplishment allowing access to archival samples for comparative analysis. LPA will play an expanded role in 21st century personalized medicine as selecting optimum therapies will require specialized tests to determine the molecular profile of the disease.

Figure 1 This figure, generated by the Hewitt team from the NCI Laboratory of Pathology and published in CEBP demonstrates the detection of seven markers from a single tumor section, and the capacity to analyze three regions of interest – normal epithelium, dysplasic epithelium.