{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,12]],"date-time":"2026-10-12T21:01:09Z","timestamp":1791838869131,"version":"4.3.4"},"reference-count":39,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2025,7,8]],"date-time":"2025-07-08T00:00:00Z","timestamp":1751932800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Universit\u00e0 Cattolica del Sacro Cuore","award":["R4124501280"],"award-info":[{"award-number":["R4124501280"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["IJMS"],"abstract":"<jats:p>Well-differentiated neuroendocrine neoplasms (NENs) are characterized by hyperexpression on the cell membrane of somatostatin receptors (SSTRs). The demonstration of SSTRs, mainly the subtype 2 (SSTR2), is the prerequisite for diagnostic and therapeutic strategies with radiolabeled somatostatin analogs (SSAs). SSTRs can be routinely demonstrated in vivo by SSA-positron emission tomography\/computed tomography (SSA-PET\/CT) and in vitro by immunohistochemistry (IHC). This systematic review and meta-analysis aimed to gather evidence from the available literature on the correlation between the in vivo PET\/CT and in vitro IHC SSTR expression in NEN patients. A systematic review and meta-analysis were conducted following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) 2020 guidelines. A comprehensive literature search was performed in PubMed\/MEDLINE and Cochrane Library, selecting studies correlating SSTR expression in NENs via IHC and SSA-PET\/CT. Data extraction, quality assessment, and statistical analysis were performed. Eleven studies met the inclusion criteria for systematic review (345 patients). Of these, eight studies (299 patients) provided sufficient quantitative data for meta-analysis. The pooled concordance between SSA-PET\/CT and IHC was 76% (95% CI: 67.7\u201384.2), indicating a good correlation between in vivo and in vitro SSTR2 expression. Heterogeneity among studies was moderate (I2 = 65%), reflecting different patient cohorts and methodologies regarding both SSA-PET\/CT and IHC. No significant publication bias was detected. Our results confirmed good agreement between in vivo tumor uptake with SSA-PET\/CT and in vitro SSTR2 expression with IHC, highlighting the potential of using IHC for clinical decision-making in NEN patients when SSA-PET\/CT is not available.<\/jats:p>","DOI":"10.3390\/ijms26146551","type":"journal-article","created":{"date-parts":[[2025,7,8]],"date-time":"2025-07-08T07:31:57Z","timestamp":1751959917000},"page":"6551","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["In Vivo Versus In Vitro Somatostatin Receptor Expression in Neuroendocrine Neoplasms: A Systematic Review and Meta-Analysis of Correlation Studies"],"prefix":"10.3390","volume":"26","author":[{"given":"Elisabetta","family":"Perrone","sequence":"first","affiliation":[{"name":"Nuclear Medicine Unit, Department of Diagnostic Imaging, Oncological Radiotherapy and Hematology, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9808-780X","authenticated-orcid":false,"given":"Giorgio","family":"Treglia","sequence":"additional","affiliation":[{"name":"Faculty of Biomedical Sciences, Universit\u00e0 della Svizzera Italiana (USI), 6900 Lugano, Switzerland"},{"name":"Division of Nuclear Medicine, Imaging Institute of Southern Switzerland, Ente Ospedaliero Cantonale, 6500 Bellinzona, Switzerland"},{"name":"Department of Nuclear Medicine and Molecular Imaging, Lausanne University Hospital, University of Lausanne, 1015 Lausanne, Switzerland"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Romina Grazia","family":"Giancipoli","sequence":"additional","affiliation":[{"name":"PET-CT Center, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy"},{"name":"European Neuro-Endocrine Tumor Society (ENETS) Center of Excellence, Fondazione Policlinico Universitario A. Gemelli IRCCS, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6000-2898","authenticated-orcid":false,"given":"Lucia","family":"Leccisotti","sequence":"additional","affiliation":[{"name":"Nuclear Medicine Unit, Department of Diagnostic Imaging, Oncological Radiotherapy and Hematology, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy"},{"name":"Section of Nuclear Medicine, Department of Radiological Sciences and Hematology, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2996-4404","authenticated-orcid":false,"given":"Guido","family":"Rindi","sequence":"additional","affiliation":[{"name":"European Neuro-Endocrine Tumor Society (ENETS) Center of Excellence, Fondazione Policlinico Universitario A. Gemelli IRCCS, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"},{"name":"Section of Anatomic Pathology, Department of Life Sciences and Public Health, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"},{"name":"Unit of Head and Neck, Thoracic and Endocrine Pathology, Department of Woman and Child Health Sciences and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Vittoria","family":"Rufini","sequence":"additional","affiliation":[{"name":"Nuclear Medicine Unit, Department of Diagnostic Imaging, Oncological Radiotherapy and Hematology, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy"},{"name":"European Neuro-Endocrine Tumor Society (ENETS) Center of Excellence, Fondazione Policlinico Universitario A. Gemelli IRCCS, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"},{"name":"Section of Nuclear Medicine, Department of Radiological Sciences and Hematology, Universit\u00e0 Cattolica del Sacro Cuore, 00168 Rome, Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2025,7,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"26","DOI":"10.1210\/endrev\/bnae022","article-title":"Structure and Function of Somatostatin and Its Receptors in Endocrinology","volume":"46","author":"Zhang","year":"2025","journal-title":"Endocr. Rev."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"1323","DOI":"10.2967\/jnumed.120.251512","article-title":"Somatostatin Receptor Imaging and Theranostics: Current Practice and Future Prospects","volume":"62","author":"Park","year":"2021","journal-title":"J. Nucl. Med."},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Hennrich, U., and Kopka, K. 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