000286664 001__ 286664 000286664 005__ 20240301121552.0 000286664 0247_ $$2pmid$$apmid:38167622 000286664 0247_ $$2ISSN$$a0097-9058 000286664 0247_ $$2ISSN$$a0022-3123 000286664 0247_ $$2ISSN$$a0161-5505 000286664 0247_ $$2ISSN$$a1535-5667 000286664 0247_ $$2ISSN$$a2159-662X 000286664 0247_ $$2doi$$a10.2967/jnumed.123.266393 000286664 037__ $$aDKFZ-2024-00028 000286664 041__ $$aEnglish 000286664 082__ $$a610 000286664 1001_ $$aSpektor, Anna-Maria$$b0 000286664 245__ $$aImmunohistochemical FAP Expression Reflects 68Ga-FAPI PET Imaging Properties of Low- and High-Grade Intraductal Papillary Mucinous Neoplasms and Pancreatic Ductal Adenocarcinoma. 000286664 260__ $$aNew York, NY$$bSoc.$$c2024 000286664 3367_ $$2DRIVER$$aarticle 000286664 3367_ $$2DataCite$$aOutput Types/Journal article 000286664 3367_ $$0PUB:(DE-HGF)16$$2PUB:(DE-HGF)$$aJournal Article$$bjournal$$mjournal$$s1704440698_12409 000286664 3367_ $$2BibTeX$$aARTICLE 000286664 3367_ $$2ORCID$$aJOURNAL_ARTICLE 000286664 3367_ $$00$$2EndNote$$aJournal Article 000286664 500__ $$a2024 Jan 2;65(1):52-58 000286664 520__ $$aPancreatic intraductal papillary mucinous neoplasms (IPMNs) are grossly visible (typically > 5 mm) intraductal epithelial neoplasms of mucin-producing cells, arising in the main pancreatic duct or its branches. According to the current 2-tiered grading scheme, these lesions are categorized as having either low-grade (LG) dysplasia, which has a benign prognosis, or high-grade (HG) dysplasia, which formally represents a carcinoma in situ and thus can transform to pancreatic ductal adenocarcinoma (PDAC). Because both entities require different treatments according to their risk of becoming malignant, a precise pretherapeutic diagnostic differentiation is inevitable for adequate patient management. Recently, our group has demonstrated that 68Ga-fibroblast activation protein (FAP) inhibitor (FAPI) PET/CT shows great potential for the differentiation of LG IPMNs, HG IPMNs, and PDAC according to marked differences in signal intensity and tracer dynamics. The purpose of this study was to biologically validate FAP as a target for PET imaging by analyzing immunohistochemical FAP expression in LG IPMNs, HG IPMNs, and PDAC and comparing with SUV and time to peak (TTP) measured in our prior study. Methods: To evaluate the correlation of the expression level of FAP and α-smooth muscle actin (αSMA) in neoplasm-associated stroma depending on the degree of dysplasia in IPMNs, 98 patients with a diagnosis of LG IPMN, HG IPMN, PDAC with associated HG IPMN, or PDAC who underwent pancreatic surgery at the University Hospital Heidelberg between 2017 and 2023 were identified using the database of the Institute of Pathology, University Hospital Heidelberg. In a reevaluation of hematoxylin- and eosin-stained tissue sections of formalin-fixed and paraffin-embedded resection material from the archive, which was originally generated for histopathologic routine diagnostics, a regrading of IPMNs was performed by a pathologist according to the current 2-tiered grading scheme, consequently eliminating the former diagnosis of 'IPMN with intermediate-grade dysplasia.' For each case, semithin tissue sections of 3 paraffin blocks containing neoplasm were immunohistologically stained with antibodies directed against FAP and αSMA. In a masked approach, a semiquantitative analysis of the immunohistochemically stained slides was finally performed by a pathologist by adapting the immunoreactive score (IRS) and human epidermal growth factor receptor 2 (Her2)/neu score to determine the intensity and percentage of FAP- and αSMA-positive cells. Afterward, the IRS of 14 patients who underwent 68Ga-FAPI-74 PET/CT in our previous study was compared with their SUVmax, SUVmean, and TTP for result validation. Results: From 98 patients, 294 specimens (3 replicates per patient) were immunohistochemically stained for FAP and αSMA. Twenty-three patients had LG IPMNs, 11 had HG IPMNs, 10 had HG IPMNs plus PDAC, and 54 had PDAC. The tumor stroma was in all cases variably positive for FAP. The staining intensity, percentage of FAP-positive stroma, IRS, and Her2/neu score increased with higher malignancy. αSMA expression could be shown in normal pancreatic stroma as well as within peri- and intraneoplastic desmoplastic reaction. No homogeneous increase in intensity, percentage, IRS, and Her2/neu score with higher malignancy was observed for αSMA. The comparison of the mean IRS of FAP with the mean SUVmax, SUVmean, and TTP of 68Ga-GAPI-74 PET/CT showed a matching value increasing with higher malignancy in 68Ga-FAPI-74 PET imaging and immunohistochemical FAP expression. Conclusion: The immunohistochemical staining of IPMNs and PDAC validates FAP as a biology-based stromal target for in vivo imaging. Increasing expression of FAP in lesions with a higher degree of malignancy matches the expectation of a stronger FAP expression in PDAC and HG IPMNs than in LG IPMNs and corroborates our previous findings of higher SUVs and a longer TTP in PDAC and HG IPMNs than in LG IPMNs. 000286664 536__ $$0G:(DE-HGF)POF4-315$$a315 - Bildgebung und Radioonkologie (POF4-315)$$cPOF4-315$$fPOF IV$$x0 000286664 588__ $$aDataset connected to DataCite, PubMed, , Journals: inrepo02.dkfz.de 000286664 650_7 $$2Other$$aFAPI 000286664 650_7 $$2Other$$aIHC 000286664 650_7 $$2Other$$aIPMN 000286664 650_7 $$2Other$$aPDAC 000286664 650_7 $$2Other$$afibroblast activation protein 000286664 650_7 $$2Other$$aα-SMA 000286664 7001_ $$aGutjahr, Ewgenija$$b1 000286664 7001_ $$aLang, Matthias$$b2 000286664 7001_ $$0P:(DE-He78)1fc3c2327d9c213c36fe740ef63e1baa$$aGlatting, Frederik Marcel$$b3$$udkfz 000286664 7001_ $$aHackert, Thilo$$b4 000286664 7001_ $$aPausch, Thomas$$b5 000286664 7001_ $$aTjaden, Christine$$b6 000286664 7001_ $$aSchreckenberger, Mathias$$b7 000286664 7001_ $$0P:(DE-He78)13a0afba029f5f64dc18b25ef7499558$$aHaberkorn, Uwe$$b8$$udkfz 000286664 7001_ $$aRöhrich, Manuel$$b9 000286664 773__ $$0PERI:(DE-600)2040222-3$$a10.2967/jnumed.123.266393$$gVol. 65, no. 1$$n1$$p52-58$$tJournal of nuclear medicine$$v65$$x0097-9058$$y2024 000286664 909CO $$ooai:inrepo02.dkfz.de:286664$$pVDB 000286664 9101_ $$0I:(DE-588b)2036810-0$$6P:(DE-He78)1fc3c2327d9c213c36fe740ef63e1baa$$aDeutsches Krebsforschungszentrum$$b3$$kDKFZ 000286664 9101_ $$0I:(DE-588b)2036810-0$$6P:(DE-He78)13a0afba029f5f64dc18b25ef7499558$$aDeutsches Krebsforschungszentrum$$b8$$kDKFZ 000286664 9131_ $$0G:(DE-HGF)POF4-315$$1G:(DE-HGF)POF4-310$$2G:(DE-HGF)POF4-300$$3G:(DE-HGF)POF4$$4G:(DE-HGF)POF$$aDE-HGF$$bGesundheit$$lKrebsforschung$$vBildgebung und Radioonkologie$$x0 000286664 9141_ $$y2024 000286664 915__ $$0StatID:(DE-HGF)0100$$2StatID$$aJCR$$bJ NUCL MED : 2022$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0200$$2StatID$$aDBCoverage$$bSCOPUS$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0300$$2StatID$$aDBCoverage$$bMedline$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0320$$2StatID$$aDBCoverage$$bPubMed Central$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0199$$2StatID$$aDBCoverage$$bClarivate Analytics Master Journal List$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)1050$$2StatID$$aDBCoverage$$bBIOSIS Previews$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0113$$2StatID$$aWoS$$bScience Citation Index Expanded$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0150$$2StatID$$aDBCoverage$$bWeb of Science Core Collection$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)1030$$2StatID$$aDBCoverage$$bCurrent Contents - Life Sciences$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)1190$$2StatID$$aDBCoverage$$bBiological Abstracts$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)0160$$2StatID$$aDBCoverage$$bEssential Science Indicators$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)1110$$2StatID$$aDBCoverage$$bCurrent Contents - Clinical Medicine$$d2023-10-24 000286664 915__ $$0StatID:(DE-HGF)9905$$2StatID$$aIF >= 5$$bJ NUCL MED : 2022$$d2023-10-24 000286664 9201_ $$0I:(DE-He78)E055-20160331$$kE055$$lE055 KKE Molekulare Radioonkologie$$x0 000286664 9201_ $$0I:(DE-He78)E060-20160331$$kE060$$lE060 KKE Nuklearmedizin$$x1 000286664 980__ $$ajournal 000286664 980__ $$aVDB 000286664 980__ $$aI:(DE-He78)E055-20160331 000286664 980__ $$aI:(DE-He78)E060-20160331 000286664 980__ $$aUNRESTRICTED