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Updated: Nov 17, 2025
Determination of Protein Expression Level in Cultured Cells by Immunocytochemistry on Paraffin-embedded Cell Blocks
Published on: May 20, 2018
Cell-blocks and immunohistochemistry
Vinod B Shidham1, Lester J Layfield2
1Department of Pathology, Wayne State University School of Medicine, Karmanos Cancer Center and Detroit Medical Center, Detroit, Michigan, USA.
Insights
Standardizing cell-block processing for immunohistochemistry (IHC) is crucial for accurate interpretation. Proper protocols ensure reliable diagnostic immunoreactivity, especially with advanced techniques like multiplex IHC and rabbit monoclonal antibodies.
Area of Science:
- Pathology
- Immunohistochemistry
- Molecular Diagnostics
Background:
- Immunohistochemistry (IHC) interpretation relies on formalin-fixed paraffin-embedded (FFPE) tissue data.
- Cell-block sections require comparable fixation and processing to FFPE tissues for accurate results.
- Non-standard protocols can lead to aberrant immunoprofiles and misinterpretation.
Purpose of the Study:
- To highlight the importance of consistent fixation and processing for cell-block immunohistochemistry.
- To discuss challenges in evaluating scant cell-block material and coordinate immunostaining patterns.
- To introduce methodologies that improve cell-block preparation and IHC analysis.
Main Methods:
- Comparison of cell-block immunostaining with FFPE tissue data.
- Discussion of standardized vs. non-standard fixation and processing protocols.
- Introduction of NextGen CelBlocking™ (NGCB) kits and the subtractive coordinate immunoreactivity pattern (SCIP) approach.
Main Results:
- Non-formalin fixatives or reagents can interfere with diagnostic immunoreactivity.
- Scant diagnostic material and lack of orientation in cell-blocks pose evaluation challenges.
- NGCB kits facilitate standardized cell-block preparation and SCIP application for improved analysis.
Conclusions:
- Consistent processing protocols are essential for reliable cell-block IHC interpretation.
- Advanced techniques like multiplex IHC and rabbit monoclonal antibodies enhance diagnostic capabilities.
- Dedicated methodologies such as NGCB kits and SCIP approach address cell-block specific challenges.
Abstract:
The interpretation of results on immunostained cell-block sections has to be compared with the cumulative published data derived predominantly from formalin-fixed paraffin-embedded (FFPE) tissue sections. Because of this, it is important to recognize that the fixation and processing protocol should not be different from the routinely processed FFPE surgical pathology tissue. Exposure to non-formalin fixatives or reagents may interfere with the diagnostic immunoreactivity pattern. The immunoprofile observed on such cell-blocks, which are not processed in a manner similar to the surgical pathology specimens, may not be representative resulting in aberrant results. The field of immunohistochemistry (IHC) is advancing continuously with the standardization of many immunomarkers. A variety of technical advances such as multiplex IHC with refined methodologies and automation is increasing its role in clinical applications. The recent addition of rabbit monoclonal antibodies has further improved sensitivity. As compared to the mouse monoclonal antibodies, the rabbit monoclonal antibodies have 10 to 100 fold higher antigen affinity. Most of the scenarios involve the evaluation of coordinate immunostaining patterns in cell-blocks with relatively scant diagnostic material without proper orientation which is usually retained in most of the surgical pathology specimens. These challenges are addressed if cell-blocks are prepared with some dedicated methodologies such as NextGen CelBloking™ (NGCB) kits. Cell-blocks prepared by NGCB kits also facilitate the easy application of the SCIP (subtractive coordinate immunoreactivity pattern) approach for proper evaluation of coordinate immunoreactivity. Various cell-block and IHC-related issues are discussed in detail.
