ihcDirect® Synaptophysin is a polyHRP conjugated rabbit monoclonal antibody (clone R1003). Synaptophysin is an abundant synaptic vesicle membrane glycoprotein, which presents in neuronal presynaptic vesicles. It is found as a granular cytoplasmic pattern in small cell lung carcinoma and reflects neurosecretory granules. Positive staining for Synaptophysin is seen in normal tissues, such as the adrenal medulla, neuronal cells, neuroendocrine cells, pineal gland, gut, and pancreatic islet cells. In disease conditions, Synaptophysin can be seen in neuroendocrine cells in tumors at all sites, including carcinoid tumors, neuroendocrine carcinoma, paraganglioma, and small cell lung carcinoma as well as pituitary, thyroid and islet cell tumors as well as the adrenal gland.