Preservation of keratin expression in oral mucosa using a novel transport medium

Cellular expression of keratins (intermediate filaments) can be demonstrated by immunocytochemistry using unfixed tissue. However, for practical reasons, provision of fresh tissue to the laboratory is often difficult. Recently a fresh tissue transport medium (Patent applied for) has been developed which allows keratin immunocytochemistry to be performed up to 4 days after biopsy. In this study oral mucosal biopsies from 10 patients were hemisected, half placed in the new transport medium at 4 degrees C and the other half immediately frozen in liquid nitrogen. After 4 days frozen sections of both halves of the biopsies were stained by immunocytochemistry using various antikeratin antibodies. The morphology and staining characteristics of the two halves of the biopsies were then assessed. No significant difference could be found in either morphology or preservation of keratin expression in specimens stored in transport medium, as compared to those in liquid nitrogen. This new transport medium may offer considerable advantage for the provision of a histologic and immunocytochemical diagnostic service.