1. Place tissue specimens directly onto wet ice or into
70% cold ethanol immediately after surgical removal or biopsy.
2. Grossly process the tissue specimen into thin sections (< 3 mm) or
cut into small pieces.
3. Place into a large container with at least 10 volumes of cold 70% ethanol
and fix overnight at 4 °C.
Note: DEPC-treated water should be used in making 70% ethanol for preserving RNA.