Neuroendocrine differentiation in primary Merkel cell carcinoma--possible prognostic significance.

BACKGROUND: The aim of this study was to examine the level of neuroendocrine differentiation to determine its association with clinicopathological parameters. PATIENTS AND METHODS: Twenty-five primary MCC samples were evaluated for neuroendocrine differentiation profiles by immunohistochemistry using antibodies to chromogranin-A, microtubule associated protein-2 and synaptophysin. The data were compared with clinical parameters to find out whether their expression correlates with prognosis. RESULTS: In general, MCC shows a high degree of neuroendocrine differentiation. A higher expression of chromogranin-A and synaptophysin associated with benign behaviour. Chromogranin-A appeared to be the most important one in predicting the course of disease. CONCLUSION: Low levels of neuroendocrine differentiation in MCC associates with poor prognosis. Chromogranin-A could be used to identify patients who might benefit from oncological treatments.