Distribution of type IV collagen in benign and malignant epithelial proliferations. An indirect immunofluorescence study on the breasts, the lungs, and the skin.

The distribution of type IV collagen in benign and malignant epithelial proliferations of the breasts, the lungs, and the skin was studied by an indirect immunofluorescence technique using specific antiserum. In benign lesions of the breasts, the staining for type IV collagen was present in all vascular and glandular basement membranes. In basal cell carcinoma of the skin, the basement membrane labeling was also found to be continuous. In malignant lesions of the breasts, the lungs, and the skin, staining for type IV collagen was seen only around well-differentiated glandular structures and in close contact to basal epidermal cells. This staining appeared as an irregular network. Of particular interest was the localization of type IV collagen in non-infiltrating lesions of the breasts and the bronchi where discontinuity in the basement membrane staining was observed. In contrast, there were no disruptions of basement membrane labeling in skin senile keratosis and in Bowen's disease. We conclude that the loss of type IV collagen seen in malignant proliferations in our study is related to overt or potential tumor cell infiltration and aggressiveness.