ENO2 and neoplasm: In addition, most tumours also exhibit neuron-specific enolase (NSE), chromogranin A (CHA), serotonin (SER) and synaptophysin (SYN).31,32 In a feline aortic body tumour, the cells were immunohistochemically positive for CHA, for SYN and, faintly, for NSE, and negative for vimentin, cytokeratin, a smooth muscle actin, glial fibrillary acidic protein, thyroglobulin and calcitonin.20