Loss of basement membrane components laminin and type IV collagen parallels the progression of oral epithelial neoplasia

Abstract

AIMS: To determine the immunohistochemical localization of basement membrane components laminin and type IV collagen in premalignant and malignant lesions of the oral epithelium. METHODS AND RESULTS: Formalin-fixed tissue sections of 12 epithelial hyperplasias with no dysplasia and 30 dysplasias, clinically diagnosed as leukoplakia and/or erythroplakia, as well as 50 invasive squamous cell carcinomas, were stained with mouse monoclonal antibodies to human laminin and type IV collagen. Statistical analysis showed that there was a linear trend for discontinuous distribution of laminin from epithelial hyperplasia to epithelial dysplasia and invasive squamous cell carcinoma (P < 0.001). Laminin staining showed a linear trend for discontinuity with increasing grade of dysplasia (P < 0.05) and was more frequently discontinuous in areas of deep tumour invasion than in central or superficial areas (P < 0.05). Brush-shaped thickening and reduplication of the basement membrane were also identified. CONCLUSIONS: Alterations in the distribution of laminin and type IV collagen in oral premalignant and malignant lesions indicate that the loss of continuity of the subepithelial basement membrane parallels the progression of the neoplastic transformation process in oral epithelium.