Expression of somatostatin receptor types 1-5 in 81 cases of gastrointestinal and pancreatic endocrine tumors. A correlative immunohistochemical and reverse-transcriptase polymerase chain reaction analysis.
Somatostatin receptors (SSTRs) have been extensively mapped in human tumors by means of autoradiography, reverse-transcriptase polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry (IHC). We analyzed the SSTR type 1-5 expression by means of RT-PCR and/or IHC in a series of 81 functioning and non-functioning gastroenteropancreatic (GEP) endocrine tumors and related normal tissues. Moreover, we compared the results with clinical, pathological and hormonal features. Forty-six cases (13 intestinal and 33 pancreatic) were studied for SSTR 1-5 expression using RT-PCR, IHC with antibodies to SSTR types 2, 3, 5 and ISH for SSTR2 mRNA. The vast majority of tumors expressed SSTR types 1, 2, 3 and 5, while SSTR4 was detected in a small minority. Due to the good correlation between RT-PCR and IHC data on SSTR types 2, 3, and 5, thirty-five additional GEP endocrine tumors were studied with IHC alone. Pancreatic insulinomas had an heterogeneous SSTR expression, while 100% of somatostatinomas expressed SSTR5 and 100% gastrinomas and glucagonomas expressed SSTR2. Pre-operative biopsy material showed an overlapping immunoreactivity with that of surgical specimens, suggesting that the SSTR status can be detected in the diagnostic work-up. It is concluded that SSTRs 1-5 are heterogeneously expressed in GEP endocrine tumors and that IHC is a reliable tool to detect SSTR types 2, 3 and 5 in surgical and biopsy specimens.
Papotti
M
M
Department of Biomedical Sciences and Oncology, University of Turin, Via Santena 7, 10126 Turin, Italy. mauro.papotti@unito.it
Bongiovanni
M
M
Volante
M
M
Allìa
E
E
Landolfi
S
S
Helboe
L
L
Schindler
M
M
Cole
S L
SL
Bussolati
G
G
D000328:Adult; D000368:Aged; D005260:Female; D015408:Gastrinoma / Q000737:chemistry; D005770:Gastrointestinal Neoplasms / Q000737:chemistry*; D015870:Gene Expression; D005935:Glucagonoma / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007340:Insulinoma / Q000737:chemistry; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009375:Neoplasms, Glandular and Epithelial / Q000737:chemistry*; D010190:Pancreatic Neoplasms / Q000737:chemistry*; D012333:RNA, Messenger / Q000032:analysis; D017481:Receptors, Somatostatin / Q000032:analysis / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013005:Somatostatinoma / Q000737:chemistry
D008565:Membrane Proteins; D012333:RNA, Messenger; D017481:Receptors, Somatostatin; C103631:somatostatin receptor 3; C098681:somatostatin receptor subtype-4; C101130:somatostatin receptor type 1; C094573:somatostatin receptor 5; C093733:somatostatin receptor 2