Neural adhesion molecule (N-CAM) in pleomorphic adenoma and carcinoma ex-pleomorphic adenoma.
BACKGROUND
The neural cell adhesion molecule (N-CAM) has been implicated in the behaviour of the adenoid cystic carcinoma. In vitro, it was demonstrated that N-CAM inhibits cell invasion. The aim of this study was to search for N-CAM in the most common salivary gland tumour that has a malignant counterpart.


METHODS
We investigated the presence of N-CAM in pleomorphic adenoma and its malignant counterpart, the carcinoma ex-pleomorphic adenoma, using the immunohistochemistry technique.


RESULTS
Neural cell adhesion molecule was expressed in all cases of pleomorphic adenoma, strongly labelling the luminal cells of the double-layered ductform structures. This expression was weaker in neoplastic myoepithelial cells and progressively diminished at a distance from the luminal cells. In carcinoma, ex-pleomorphic adenoma N-CAM was either totally absent or faintly present at the apical pole of the few luminal cells.


CONCLUSIONS
As a result of the peculiar distribution of N-CAM in pleomorphic adenoma, we speculated that N-CAM behaves as a tumour-suppressor molecule, which is expressed in the benign neoplasm and which is down-regulated after malignancy, when the tumour assumes an invasive behaviour.
Saleh
E R M
ER
School of Dentistry, University of São Paulo, SP, Brazil.
França
C M
CM
Marques
M M
MM
D000230:Adenocarcinoma / Q000473:pathology*; D008949:Adenoma, Pleomorphic / Q000473:pathology*; D004396:Coloring Agents; D015536:Down-Regulation; D004847:Epithelial Cells / Q000473:pathology; D006801:Humans; D009130:Muscle, Smooth / Q000473:pathology; D019006:Neural Cell Adhesion Molecules / Q000032:analysis*; D018987:Salivary Ducts / Q000473:pathology; D012468:Salivary Gland Neoplasms / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000032:analysis
D004396:Coloring Agents; D019006:Neural Cell Adhesion Molecules; D025521:Tumor Suppressor Proteins