Synaptophysin Identified in Metastases of Neuroendocrine Tumors by Immunocytochemistry and Immunoblotting

Abstract

Synaptophysin, an Mr 38,000 integral membrane glycoprotein of neurotransmitter vesicles, has been identified in diverse primary neuroendocrine (NE) tumors of both neural and epithelial origin (Wiedenmann and co-workers, Proc Natl Acad Sci USA 1986; 83: 3500-3504). In the present study, metastases of several types of NE tumors, including medullary thyroid carcinoma, gastrinoma, insulinoma, small (oat) cell carcinoma of the lung, gastrointestinal carcinoid, and neuroblastoma, were examined for the presence of synaptophysin by immunocytochemistry, with the use of tissue sections as well as centrifuged cell suspensions and by immunoblotting of tumor proteins. The results show that expression of synaptophysin can be maintained during formation of metastases. Therefore, the authors propose that synaptophysin antibodies be used for the positive identification of metastatic NE tumors, notably in differential diagnosis. The possible implications of these findings for tumor diagnosis are discussed.

Patterns of expression of cytoskeletal proteins in human thyroid gland and thyroid carcinomas

“…[5,52,125,126]), which in our study was based on both immunocytochemistry and the positive identification of polypeptide NF-L in biochemical analyses, is in contrast to the absence of neurofilament protein in the seven tumors described by Buley et al [15]. [5,52,125,126]), which in our study was based on both immunocytochemistry and the positive identification of polypeptide NF-L in biochemical analyses, is in contrast to the absence of neurofilament protein in the seven tumors described by Buley et al [15].…”

The tumor microenvironment: CXCR4 is associated with distinct protein expression patterns in neuroblastoma cells

“…The significance of these differences is unknown and we are unable to judge, at this time, whether the increased expression of synaptophysin and CD56 by STH cells is related to the malignancy phenotype of these cells. Although synaptophysin is differentiation-associated molecule of neuroendocrine cells [28], there are a few reports on its expression on neuroblastoma metastases [6,29]. Is the higher expression of synaptophysin by STH due to the fact that these cells are more highly differentiated than STL cells or more prone to metastasize?…”

“…The neural cell adhesion molecule (NCAM, CD56) and synaptophysin, a neuroendocrine (NE) cell specific product are common markers for NE tumors [6,7].…”

Secretory vesicle and cell surface markers for human endocrine pancreatic and pituitary tumors

“…Since synaptophysin has also been found in all pancreatic endocrine tumors examined [24,[70][71][72], this protein can be regarded as a general marker for these tumors. Insulinomas are the most frequent of the relatively rare endocrine pancreatic tumors (for refs.…”