{"entity": "publication", "iuid": "c79424bdacc14f898c66b0a94fcae8c8", "timestamp": "2026-08-22T07:48:10.667Z", "links": {"self": {"href": "https://publications-affiliated.scilifelab.se/publication/c79424bdacc14f898c66b0a94fcae8c8.json"}, "display": {"href": "https://publications-affiliated.scilifelab.se/publication/c79424bdacc14f898c66b0a94fcae8c8"}}, "title": "HER3 PET Imaging: 68Ga-Labeled Affibody Molecules Provide Superior HER3 Contrast to 89Zr-Labeled Antibody and Antibody-Fragment-Based Tracers.", "authors": [{"family": "Rinne", "given": "Sara S", "initials": "SS", "orcid": "0000-0003-2141-3982", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/3aea3edd98b441c98bb527b1e0c911f5.json"}}, {"family": "Leitao", "given": "Charles Dahlsson", "initials": "CD"}, {"family": "Abouzayed", "given": "Ayman", "initials": "A"}, {"family": "Vorobyeva", "given": "Anzhelika", "initials": "A", "orcid": "0000-0002-4778-3909", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/99703faa11ab4c19aff2f426f61c3134.json"}}, {"family": "Tolmachev", "given": "Vladimir", "initials": "V", "orcid": "0000-0002-6122-1734", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/896ae9fae8b74251afe11b4354c62794.json"}}, {"family": "St\u00e5hl", "given": "Stefan", "initials": "S"}, {"family": "L\u00f6fblom", "given": "John", "initials": "J", "orcid": "0000-0001-9423-0541", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/bf8479d43c1c45efb85ba0c0da634aeb.json"}}, {"family": "Orlova", "given": "Anna", "initials": "A", "orcid": "0000-0001-6120-2683", "researcher": {"href": "https://publications-affiliated.scilifelab.se/researcher/1c374f429702489494c05f84f298b4b7.json"}}], "type": "journal article", "published": "2021-09-24", "journal": {"title": "Cancers (Basel)", "issn": "2072-6694", "volume": "13", "issue": "19", "issn-l": "2072-6694"}, "abstract": "HER3 (human epidermal growth factor receptor type 3) is a challenging target for diagnostic radionuclide molecular imaging due to the relatively modest overexpression in tumors and substantial expression in healthy organs. In this study, we compared four HER3-targeting PET tracers based on different types of targeting molecules in a preclinical model: the 89Zr-labeled therapeutic antibody seribantumab, a seribantumab-derived F(ab)2-fragment labeled with 89Zr and 68Ga, and the 68Ga-labeled affibody molecule [68Ga]Ga-ZHER3. The novel conjugates were radiolabeled and characterized in vitro using HER3-expressing BxPC-3 and DU145 human cancer cells. Biodistribution was studied using Balb/c nu/nu mice bearing BxPC-3 xenografts. HER3-negative RAMOS xenografts were used to demonstrate binding specificity in vivo. Autoradiography was conducted on the excised tumors. nanoPET/CT imaging was performed. New conjugates specifically bound to HER3 in vitro and in vivo. [68Ga]Ga-DFO-seribantumab-F(ab')2 was considered unsuitable for imaging due to the low stability and high uptake in normal organs. The highest tumor-to-non-tumor contrast with [89Zr]Zr-DFO-seribantumab and [89Zr]Zr-DFO-seribantumab-F(ab')2 was achieved at 96 h and 48 h pi, respectively. Despite lower tumor uptake, [68Ga]Ga-ZHER3 provided the best imaging contrast due to the fastest clearance from blood and normal organs. The results of our study suggest that affibody-based tracers are more suitable for PET imaging of HER3 expression than antibody- and antibody-fragment-based tracers.", "doi": "10.3390/cancers13194791", "pmid": "34638277", "labels": [], "xrefs": [{"db": "pmc", "key": "PMC8508546"}, {"db": "pii", "key": "cancers13194791"}], "notes": [], "created": "2026-08-21T13:01:47.341Z", "modified": "2026-08-21T13:01:47.376Z"}