Chromogenic multiplex IHC; the future of immunohistochemistry for the practicing pathologist and for research

The development of many different chromogens for light microscopy gives us the opportunity to explore different usage of multiplex immunohistochemistry (IHC) for clinical diagnostic purposes as well as for research. The main advantage over the immunofluorescence (IF) multiplex technology is that a special microscope or a dark room for review of the slide is not required and the pathologist can easily recognize the morphology of the specimen evaluated, giving instantly a multi-parameter semi-quantitative assessment. Also by using, image analysis and artificial intelligence (AI) algorithms, an accurate spatial and cellular distribution of the cellular components of interest can be achieved. The disadvantage is that we still have limited number of chromogens to use, and the co-expression of colors in a single cellular compartment, if more than two, is requiring image analysis algorithms.
In this presentation you will see examples of potential clinical usage of light microscopy chromogenic multiplex IHC for diagnostic purposes. This has applications to surgical pathology as well as cytology specimens; In other words how you can replace IHC-panels of different antibodies with Multiplex IHC; or how to combine in-situ-hybridization (ISH) with protein expression on the same slide. This presentation will also demonstrate the use of Multiplex chromogenic IHC in the research setting, with examples of evaluation of tumor micro-environment with quantitative and spatial distribution of different cellular components.
This work was performed on the Discovery BechMark Ultra and partially supported by Roche Tissue Diagnostics. The Image Analysis Algorithms were custom created for the Department of Pathology, Thomas Jefferson Universiry hospital with the VisioPharm Image Analysis software.

Learning Objectives:
1. The use of chromogenic multiplex IHC in research
2. The future of chromogenic multiplex IHC in Diagnostic Cytopathology
3. The future of chromogenic multiplex IHC in Diagnostic Surgical Pathology