For Heat Induced Epitope Retrieval of paraffin-embedded tissue samples, what should be the pH of the retrieval buffer?

In house, we most commonly use basic antigen retrieval buffer at pH 9 (Catalog # VCTS021). However, antigen retrieval depends on the tissue and one should always test if antigen retrieval is necessary and also test other antigen retrieval conditions to determine what works best for the specific tissue being stained. R&D Systems offers ready-to-use Antigen Retrieval reagents at various pHs - Catalogs #s VCTS021, VCTS022, and VCTS023.