Immunohistochemical localization of type I, III, IV, V, and VI collagens and laminin in neurofibroma and neurofibrosarcoma

By using antibodies to type I, III, IV, V, and VI collagens and laminin, we examined the localization of interstitial collagens and basement membrane components with indirect immunofluorescence and immunoelectron microscopy (IEM). Furthermore, the morphological changes of these collagens in malignant transformation were investigated. In neurofibroma, IEM showed type I, III, and V collagens to be present diffusely on cross-striated collagen fibrils, whereas type VI collagen was present between the fibrils. Type IV collagen and laminin were observed to surround tumor cells. In neurofibrosarcoma, tumor collagen bundles that reacted with antibodies to type I, III, V, and VI collagens were irregularly arranged. Immunofluorescent deposits that reacted with anti-type IV collagen and anti-laminin antibodies were decreased in number, showing a thin and sparse arrangement.