Abstract | OBJECTIVE: The overexpression of somatostatin receptor 2 (sst2) in neuroendocrine tumors is the molecular basis for diagnostic and therapeutic application of the stable somatostatin analog octreotide. Recent evidence has shown that the immunocytochemical evaluation of sst2A status is of value for predicting response to octreotide therapy and disease prognosis. However, due to the lack of monoclonal and limited availability of specific polyclonal anti-sst2A antibodies, only very few patients can currently benefit from in vitro sst2 evaluation. METHODS: In the present study, we extensively characterized the novel rabbit monoclonal anti-sst2A antibody (clone UMB-1) using tissues from sst2-deficient mice and their wild-type littermates. UMB-1 was then subjected to a comparative study of immunohistochemistry on a series of histological specimens from formalin-fixed, paraffin-embedded human tumors and adjacent normal tissues. RESULTS: Immunoprecipitation experiments unequivocally demonstrated that UMB-1 selectively detected its cognate sst2A and did not cross-react with other proteins present in crude tissue homogenates. The UMB-1 monoclonal antibody, when compared with currently available polyclonal antisera, yielded several times more effective immunohistochemical staining of fixed-embedded tissues with a predominance of plasma membrane staining and very low cytoplasmic signal even without heat-based antigen retrieval. In addition, dual immunofluorescence revealed for the first time that the sst2A is present on not only gastrin-containing but also ghrelin-containing cells in human gastric mucosa. CONCLUSION:
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Authors | Thomas Fischer, Christian Doll, Stefan Jacobs, Angela Kolodziej, Ralf Stumm, Stefan Schulz |
Journal | The Journal of clinical endocrinology and metabolism
(J Clin Endocrinol Metab)
Vol. 93
Issue 11
Pg. 4519-24
(Nov 2008)
ISSN: 0021-972X [Print] United States |
PMID | 18697876
(Publication Type: Journal Article)
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Chemical References |
- Antibodies, Monoclonal
- Receptors, Somatostatin
- somatostatin receptor sst2A
- somatostatin receptor 2
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Topics |
- Animals
- Antibodies, Monoclonal
- Cross Reactions
- Female
- Humans
- Immunohistochemistry
- Male
- Mice
- Mice, Knockout
- Neoplasms
(genetics, metabolism, pathology)
- Rabbits
- Receptors, Somatostatin
(deficiency, genetics, metabolism)
- Reference Values
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