Aim: The significance of immunohistochemistry standardization became important with the disclosure of alarmingly high records of inconsistent results in the assessments of HER-2/neu expression status in women with breast cancers.
Formalin-Fixed-Paraffin-Embedded tissue usually presents with conformational macromolecular changes, masking the epitope with sub-optimal staining of HER- 2/neu protein. The pH of epitope retrieval solution appears to significantly influence the completion of the unmasking process. The present study therefore examines the impact of commercial buffers on epitope retrieval of ‘HER-2/neu’ protein so as to optimize diagnosis and management of breast cancers.
Methods: The study examined three pH buffers, non-retrieved sections and distilled water as a control on a 3+ HER-2/neu FFPE tissue block by water-bath epitope retrieval procedure and subsequently stained immunohistochemically.
Results: The pH of the buffers does not significantly influence the staining quality of HER-2/neu protein. However, pH 6 appears to be the most optimal as associated with other buffers examined.
Conclusion: pH 6 buffer in conjunction with water-bath procedure is strongly recommended as the first-choice buffer for epitope retrieval of HER-2/neu protein.
Keywords: pH, Buffers, Epitope Retrieval, HER-2/neu, Immunohistochemistry
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