Anti-synaptophysin interacts with neuroendocrine cells found in the human adrenal medulla, carotid body, skin, pituitary gland, thyroid, lungs, pancreas, and gastrointestinal mucosa. This antibody is used to detect normal neuroendocrine cells, as well as neuroendocrine tumors. A diffuse, finely granular staining within the cytoplasm is noted, which likely relates to how the antigen is distributed in neurosecretory vesicles. The expression of synaptophysin does not depend on the existence of NSE or any other neuroendocrine markers. Anti-synaptophysin serves as an independent, broad-spectrum marker for neural and neuroendocrine differentiation.