Immunohistochemical localization of laminin, type IV and type V collagen in basal cell carcinoma

Laminin, type IV and type V collagen were localized in twenty-five basal cell carcinomas (BCCs) by immunofluorescence. All basal cell carcinomas were separated from the connective tissue by a continuous basement membrane (BM) which always contained the three antigenic determinants. Nodular and cystic BCCs, but not pagetoid BCCs, contain linear and globular deposits of these BM components. The linear deposits probably represent BM debris that remains undigested and the globular deposits correspond to residual cytoplasmic fragments occurring during apoptosis. These results suggest that BM components are synthesized by epithelial cells and are secreted to polymerize at the dermo-epidermal junction.