<prompt> Which of the following markers is not typically expressed by neuroendocrine tumours?SynaptophysinChromograninCD56CK7  <response>: CK7 is an epithelial cell marker and is positive in carcinomas especially the epithelial tumours arising from foregut. The following immunohistochemical markers are positive in neuroendocrine neoplasms: Synaptophysin Chromogranin A CD56 Neuron specific enolase NSE 