Distribution of laminin and collagen type-IV in benign and malignant lesions of melanocytic origin.

Using antisera for two specific basement membrane (b.m.) antigens such as laminin and collagen type-IV, together with electron microscopy, we have shown that fully antigenic b.m. and morphologically typical basal lamina (b.l.) are associated with normal and transformed cells of the melanocyte lineage in different ways. Thus, while b.m. and b.l. surround individual choroidal melanocytes, intradermal nevus cells and cells of blue nevi are not detectable at the periphery of resting and proliferating epidermal melanocytes. They have a low degree of expression with a heterogeneous pattern of distribution in primary and metastatic melanoma. This heterogeneity is present within single metastases and among autologous metastases. These findings indicate that the presence of b.m. can be an additional marker for cells of the melanocyte lineage and should be considered when applying serological means for the detection and control of neoplasms of melanocytic origin.