title: Somatostatin receptor expression related to TP53 and RB1 alterations in pancreatic and extrapancreatic neuroendocrine neoplasms with a Ki67-index above 20.
abstract: Somatostatin receptor 2A expression is a feature of well-differentiated neuroendocrine neoplasms and is important for their diagnosis and therapy. Little is known about somatostatin receptor 2A expression in poorly differentiated neuroendocrine neoplasms in relation to TP53 and RB1 status and how these features may contribute to the separation of well from poorly differentiated neuroendocrine neoplasms with a proliferation index above 20%. This study investigates the expression of somatostatin receptors, p53 and Rb1, and TP53 alterations in pancreatic and extrapancreatic well and poorly differentiated neuroendocrine neoplasms (Ki67-index >20%). Thirty-seven poorly differentiated neuroendocrine neoplasms of pancreatic (n=12) and extrapancreatic origin (n=25) as well as 10 well-differentiated neuroendocrine neoplasms of the pancreas (n=9) and rectum (n=1) with a Ki67-index >20% were immunostained for synaptophysin, chromogranin A, Ki67, CD56, p53, Rb1, ATRX, DAXX, progesterone receptor, somatostatin receptor 2A, somatostatin receptor 5, and cytokeratin 20, and sequenced for TP53, exons 5-9. Somatostatin receptor 2A was positive in 6/37 of poorly differentiated and in 8/10 of well-differentiated neuroendocrine neoplasms. One well-differentiated and two poorly differentiated neuroendocrine neoplasms expressed somatostatin receptor 5. Abnormal nuclear p53 and Rb1 staining was found in 29/37 and 22/37 poorly differentiated neuroendocrine neoplasms, respectively, whereas all well-differentiated neuroendocrine neoplasms showed normal p53 and Rb1 expression. TP53 gene alterations were restricted to poorly differentiated neuroendocrine neoplasms (24/34) and correlated well with p53 expression. All cases were progesterone receptor negative. Somatostatin receptor 2A expression is not limited to well-differentiated neuroendocrine neoplasms but also occurs in 16% of poorly differentiated neuroendocrine neoplasms from various sites. Most poorly differentiated neuroendocrine neoplasms are characterized by TP53 alterations and Rb1 loss, usually in the absence of somatostatin receptor 2A expression. In the pancreas, these criteria contribute to separate well-differentiated neuroendocrine neoplasms with a Ki67-index above 20% from poorly differentiated neuroendocrine neoplasms.
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Konukiewitz
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Anna Melissa
authors.initials: AM
authors.lastname: Schlitter
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Jesinghaus
authors.affiliation: Division of Chronic Inflammation and Cancer, German Cancer Research Center (DKFZ), Heidelberg, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Pfister
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Steiger
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Angela
authors.initials: A
authors.lastname: Segler
authors.affiliation: Institute of Pathology, Friedrich-Alexander University Erlangen-Nuremberg, University Hospital, Erlangen, Germany.
authors.forename: Abbas
authors.initials: A
authors.lastname: Agaimy
authors.affiliation: Institute of Pathology, University Hospital of Tuebingen, Tuebingen, Germany.
authors.forename: Bence
authors.identifier: 0000-0002-7311-3343
authors.initials: B
authors.lastname: Sipos
authors.affiliation: Institute of Pathology, Sacro Cuore Hospital of Negrar, Verona, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Zamboni
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Wilko
authors.initials: W
authors.lastname: Weichert
authors.affiliation: Institute of Pathology, Heinrich-Heine-University, Düsseldorf, Germany.
authors.forename: Irene
authors.initials: I
authors.lastname: Esposito
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Pfarr
authors.affiliation: Institute of Pathology, Technical University of Munich, Munich, Germany.
authors.forename: Günter
authors.initials: G
authors.lastname: Klöppel
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000378:metabolism* / Q000473:pathology; D010179:Pancreas / Q000378:metabolism* / Q000473:pathology; D010190:Pancreatic Neoplasms / Q000378:metabolism* / Q000473:pathology; D017481:Receptors, Somatostatin / Q000378:metabolism*; D056286:Retinoblastoma Binding Proteins / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; C000606393:RB1 protein, human; D017481:Receptors, Somatostatin; D056286:Retinoblastoma Binding Proteins; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D044767:Ubiquitin-Protein Ligases