Virtual microscopy as an enabler of automated/quantitative assessment of protein expression in TMAs

Tissue Microarrays facilitate high-throughput immuohistochemistry; however, there are key bottlenecks apparent in their analysis, particularly when conducting microscope-based manual reviews. Traditionally Tissue Microarray assessments were performed using a microscope where results were either transcribed or dictated and subsequently entered into flat-file spreadsheets. This process is labour intensive, prone to error and negates the advantages of the high-throughput Tissue Microarray format. In addition, human interpretations of staining intensity parameters are highly subjective and therefore prone to inter- and intra-observer variability. The advent of Virtual Slides has permitted the review of tissue slides across the Internet. In addition, this new technology enables the creation of software solutions to assist in the manual and automated review of Tissue Microarrays, through the use of computer aided image analysis. There are numerous academically developed and commercially available applications which assist in Tissue Microarray reviews; functionality of these systems range in complexity and application domains. The review which follows describes these systems and outlines technical considerations to be assessed when deciding on a Tissue Microarray workflow solution.