Keratin antigen retrieval in oral mucosal biopsies using microwave processing

Area of Science:

• Histopathology
• Immunohistochemistry
• Biochemistry

Background:

• Monoclonal antibodies to keratins typically perform optimally on fresh frozen tissue.
• Formaldehyde fixation, standard in clinical practice, limits keratin assessment in retrospective studies and archival material.
• Antigen retrieval methods, like microwave radiation, are successful for other markers but less explored for keratins.

Purpose of the Study:

• To evaluate the efficacy of microwave-assisted antigen retrieval for keratin immunolabelling in formalin-fixed oral mucosal biopsies.
• To assess the performance of a panel of six well-characterized antikeratin antibodies after microwave processing.

Main Methods:

• Oral mucosal biopsies were divided into fresh frozen and formalin-fixed samples.
• Tissue sections were processed using the peroxidase avidin biotin technique.
• Keratin expression was compared between frozen, dewaxed, and microwave-treated dewaxed sections using six specific antikeratin antibodies.

Main Results:

• Microwave processing resulted in an overall 25% improvement in keratin identification.
• The effectiveness of microwave retrieval varied among the different antikeratin antibodies tested.
• Specific antibodies demonstrated differential performance post-retrieval.

Conclusions:

• Microwave antigen retrieval is a valuable adjunct for analyzing keratins in archival formalin-fixed tissue.
• This method expands the utility of antikeratin antibodies in retrospective studies and tumor diagnosis.
• The study highlights the potential of optimizing immunohistochemical techniques for challenging sample types.