Staining patterns of human pre-malignant oral epithelium and squamous cell carcinomas by monoclonal anti-keratin antibodies.

Formalin-fixed, paraffin-embedded biopsies of metaplastic keratinized oral mucosa (fibromas and leukoplakias), oral mucosa with epithelial dysplasia and oral squamous cell carcinomas were stained with two monoclonal anti-keratin antibodies (AE1 and AE2). Intense suprabasal staining was seen with AE1 in metaplastic keratinized epithelium, whereas staining of adjacent normal unkeratinized epithelium generally was restricted to basal cells. In dysplastic epithelium and squamous cell carcinomas, staining with AE1 revealed a highly disturbed anti-keratin staining pattern. AE2 stained metaplastic keratinized epithelium in a suprabasal pattern but adjacent unkeratinized epithelium did not stain. In dysplastic epithelium and squamous cell carcinomas, AE2 staining was variable and sometimes absent. Further studies are indicated to clarify whether changes in anti-keratin staining patterns can be used for diagnostic and prognostic purposes.