Immunoelectron microscopy on material retrieved from paraffin: Accurate sampling on the basis of stained paraffin sections

As a rule, immunoelectron microscopy (immuno-EM) is performed on fresh mate rial processed according to specialized methods (e.g., freezing or embeddin g in hydrophilic resins). Paraffin-embedded tissue has only occasionally be en used as a source of material for immuno-EM; this was usually as a last r esort, when no fresh material was available. The authors used archival form alin-fixed. paraffin-embedded basal cell carcinomas for studying the fine-s tructural distribution of the cell surface molecule CD44 and its variants, as well as some other antigens. The results demonstrate, firstly, that para ffin-embedded material is far more suitable for immuno-EM than frequently a ssumed and, secondly, that the use of paraffin-embedded material enables hi ghly accurate sampling on the basis of immunohistochemically or conventiona lly stained light microscopic sections.