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What procedures should be in place to ensure the optimal preparation of intact surgical resection tissue samples for protein analysis using immunocytochemistry?
The following procedures should be in place:
• Instructions for theatre staff for control of the interval of cold ischaemic time from removal of the tissue to immersion in formalin. Note: for certain analysis (Box 1.1) specific guidelines may apply.
• Bulky samples will require slicing after reception into the laboratory to ensure adequate fixation. Formalin fixation times should be carefully controlled to avoid under or over fixation.
• Blocks of representative tissue will need to be selected for paraffin wax processing and standardised processing schedules should be followed that are appropriate for the sample type.
• Embedding in paraffin wax needs to be undertaken to ensure that relevant areas of each tissue block are present in the cut sections. These should be cut at 2-4m thickness and for immunocytochemistry mounted on adhesive coated slides.
• Haematoxylin and eosin staining should be done to allow for morphological assessment of sections from each block. If this reveals problems with preservation or inadequate tissue representation then consideration should be given to paraffin processing additional blocks with possible alteration of the processing schedule. Note: morphological assessment will often lead to an initial diagnosis and also the selection of appropriate blocks for immunocytochemistry.
• Immunocytochemistry with an antibody or antibodies should be undertaken using specific protocols. Note: If there is a concern that antigen preservation in the sections is not adequate a relevant antibody (see Table 3) can be used to assess for this. Failure to demonstrate antigen preservation may necessitate the re-processing of additional blocks of tissue.