NEURAL CELL-ADHESION MOLECULE IMMUNOREACTIVITY IN MERKEL CELLS AND MERKEL CELL TUMORS

We have analysed the expression of the neural cell adhesion molecule ( NCAM) in normal Merkel cells of pig and human skin, and in nine neuroe ndocrine carcinomas of the skin (Merkel cell carcinomas). NCAM immunor eactivity was observed in virtually all Merkel cells, both in epidermi s and vibrissae of pig snout skin and in human epidermis. Immunostaini ng surrounded the entire surface; of Merkel cells and was not restrict ed to the contact areas between Merkel cells and nerve terminals, All Merkel cell carcinomas studied were also positive for NCAM. The immuno staining pattern of the tumour cells was similar to that observed in n ormal Merkel cells; the immunoreactivity was confined to the cell memb ranes. These results suggest that NCAM may be used as an immunohistoch emical marker for both Merkel cells and Merkel cell tumours.