Polysialylated N-CAM, chromogranin A and B, and secretogranin II in neuroendocrine tumours of the lung

Highly alpha 2-8-sialylated N-CAM (neural cell adhesion molecule) impairs N-CAM-mediated cell adhesion. We investigated polysiaN-CAM immunoreactivity in a range of neuroendocrine lung tumours: 15 typical carcinoids, 21 atypical carcinoids, 2 large cell neuroendocrine carcinomas and 13, small cell lung carcinomas were selected on a morphological basis and by their immunoreactivity for chromogranin A and B and secretogranin II. A progressive loss of chromogranin expression, particularly of chromogranin B, was paralleled by the up-regulation of polysiaN-CAM in histologically more aggressive rumours (P = 0.001). These data support the hypothesis that loss of cell-cell adhesion properties might be a relevant factor in the origin of the aggressivity of lung neuroendocrine rumours.