Tissues are snap frozen in liquid nitrogen immediately after excision, and embedded in OCT. All US Biological’s frozen tissue products, including frozen tissue arrays, frozen tissue sections, and frozen tissue panels, can be used for both immunohistochemistry and in situ hybridization. These products are ideal for rapid cellular localization of RNA and protein expression, especially for antibodies that don't recognize paraffin embedded tissue. At least one of the tissue slides from each lot was stained with H & E to ensure quality.