synaptophysin
Pronunciation: si-NAP-toe-FY-sin
A synaptic vesicle glycoprotein used as an immunohistochemical marker for neuroendocrine differentiation.
Full Definition
Synaptophysin is a calcium-binding glycoprotein found in presynaptic vesicles and neuroendocrine secretory granules throughout the nervous system and neuroendocrine tissues. In diagnostic pathology, synaptophysin serves as a reliable pan-neuroendocrine marker used to identify tumors of neuroendocrine origin. The protein is involved in synaptic vesicle exocytosis and membrane recycling processes. Immunohistochemical staining for synaptophysin, often combined with chromogranin A, helps pathologists distinguish neuroendocrine tumors from other malignancies with similar morphologic features. Expression levels may vary depending on tumor differentiation and grade.
Usage
Usage note: Standard neuroendocrine marker alongside chromogranin A in tumor diagnosis.
In Context
- "The tumor cells showed strong cytoplasmic staining for synaptophysin, confirming neuroendocrine differentiation." — Pathology report
- "Both chromogranin A and synaptophysin were positive, supporting the diagnosis of neuroendocrine carcinoma." — Immunohistochemistry report