EDTA-polyvinylpyrrolidone as a preservation medium for immunohistochemistry

In a solution on 7% EDTA and 5% polyvinylpyrrolidone in 0.1 mol/l. Tris buffer, pH = 6.95, tissues samples can be stored at room temperature for 1 week without detectable loss of structural integrity or antigenicity (as demonstrated in immunohistochemistry with monoclonal antibodies to intermediate filament proteins).