INTEGRINS AND BASEMENT-MEMBRANE PROTEINS IN SKIN CARCINOMAS

The topography of some integrins and basement membrane proteins in cut aneous basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) has been studied by immunohistochemistry. The typical cell-to-cell dis tribution of alpha 2 beta 1 and alpha 3 beta 1 of normal epidermis bec omes pericellular in both BCC and SCC cells. BCC and SCC also showed d ifferent patterns of expression of alpha 6 beta 4, the integrin normal ly located at the basal surface of basal epidermal keratinocytes. SCC showed high expression and pericellular distribution of alpha 6 beta 4 , while BCC did not express alpha 6 beta 4 at all also in Western blot ting. The basement membrane was markedly different in the two tumor ty pes. Laminin and collagen type IV were conserved in the basement membr ane zone of both tumors while nicein/kalinin was absent from BCC cells . The simultaneous loss of expression of alpha 6 beta 4 and nicein/kal inin in BCC cells but not in SCC cells indicates that alpha 6 beta 4 a nd one potential ligand may be co-regulated in both BCC and SCC. We su ggest a role for this phenomenon in the pathogenesis of these epiderma l tumors.