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The aim of this prospective clinical study was to evaluate the potential of the prostate specific membrane antigen (PSMA) targeting ligand, [ 68 Ga]-PSMA-Glu-NH-CO-NH-Lys-2-naphthyl-L-Ala-cyclohexane-DOTA ([ 68 Ga]Ga-PSMA-617) as a positron emission tomography (PET) imaging biomarker in recurrent glioblastoma patients. Patients underwent [ 68 Ga]Ga-PSMA-617 and O-(2-[ 18 F]-fluoroethyl)-L-tyrosine ([ 18 F]FET) PET scans on two separate days. [ 68 Ga]Ga-PSMA-617 tumour selectivity was assessed by comparing tumour volume delineation and by assessing the intra-patient correlation between tumour uptake on [ 68 Ga]Ga-PSMA-617 and [ 18 F]FET PET images. [ 68 Ga]Ga-PSMA-617 tumour specificity was evaluated by comparing its tumour-to-brain ratio (TBR) with [ 18 F]FET TBR and its tumour volume with the magnetic resonance imaging (MRI) contrast-enhancing (CE) tumour volume. Ten patients were recruited in this study. [ 68 Ga]Ga-PSMA-617-avid tumour volume was larger than the [ 18 F]FET tumour volume ( p = 0.063). There was a positive intra-patient correlation (median Pearson r = 0.51; p < 0.0001) between [ 68 Ga]Ga-PSMA-617 and [ 18 F]FET in the tumour volume. [ 68 Ga]Ga-PSMA-617 had significantly higher TBR ( p = 0 .002) than [ 18 F]FET. The [ 68 Ga]Ga-PSMA-617-avid tumour volume was larger than the CE tumour volume ( p = 0.0039). Overall, accumulation of [ 68 Ga]-Ga-PSMA-617 beyond [ 18 F]FET-avid tumour regions suggests the presence of neoangiogenesis in tumour regions that are not overly metabolically active yet. Higher tumour specificity suggests that [ 68 Ga]-Ga-PSMA-617 could be a better imaging biomarker for recurrent tumour delineation and secondary treatment planning than [ 18 F]FET and CE MRI.

Accurate and early detection of biomarkers provides the molecular evidence for disease management, allowing prompt actions and timely treatments to save lives. Multivalent biomolecular interactions between the probe and biomarker as well as controlled probe orientation on material surfaces are keys for highly sensitive detection. Here we report the bioengineering of programmable and multifunctional nanoprobes, which can provide rapid, specific and highly sensitive detection of emerging diseases in a range of widely used diagnostic systems. These nanoprobes composed of nanosized cell wall fragments, termed as synthetic bionanofragments (SynBioNFs), are generated by the fragmentation of genetically programmed yeast cells. SynBioNFs display multiple copies of biomolecules for high-affinity target binding and molecular handles for the precisely orientated attachment on surfaces used in diagnostic platforms. SynBioNFs are demonstrated for the capture and detection of SARS-CoV-2 virions using multiple diagnostic platforms, including surface-enhanced Raman scattering, fluorescence, electrochemical and colorimetric-based lateral flow systems with sensitivity comparable with the gold-standard reverse-transcription quantitative polymerase chain reaction., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

Rationale: An antibody-drug conjugate (ADC) is a targeted therapy consisting of a cytotoxic payload that is linked to an antibody which targets a protein enriched on malignant cells. Multiple ADCs are currently used clinically as anti-cancer agents significantly improving patient survival. Herein, we evaluated the rationale of targeting the cell surface oncoreceptor CUB domain-containing protein 1 (CDCP1) using ADCs and assessed the efficacy of CDCP1-directed ADCs against a range of malignant tumors. Methods: CDCP1 mRNA expression was evaluated using large transcriptomic datasets of normal/tumor samples for 23 types of cancer and 15 other normal organs, and CDCP1 protein expression was examined in 34 normal tissues, >300 samples from six types of cancer, and in 49 cancer cell lines. A recombinant human/mouse chimeric anti-CDCP1 antibody (ch10D7) was labelled with 89 Zirconium or monomethyl auristatin E (MMAE) and tested in multiple pre-clinical cancer models including 36 cancer cell lines and three mouse xenograft models. Results: Analysis of CDCP1 expression indicates elevated CDCP1 expression in the majority of the cancers and restricted expression in normal human tissues. Antibody ch10D7 demonstrates a high affinity and specificity for CDCP1 inducing cell signalling via Src accompanied by rapid internalization of ch10D7/CDCP1 complexes in cancer cells . 89 Zirconium-labelled ch10D7 accumulates in CDCP1 expressing cells enabling detection of pancreatic cancer xenografts in mice by PET imaging. Cytotoxicity of MMAE-labelled ch10D7 against kidney, colorectal, lung, ovarian, pancreatic and prostate cancer cells in vitro , correlates with the level of CDCP1 on the plasma membrane. ch10D7-MMAE displays robust anti-tumor effects against mouse xenograft models of pancreatic, colorectal and ovarian cancer. Conclusion: CDCP1 directed imaging agents will be useful for selecting cancer patients for personalized treatment with cytotoxin-loaded CDCP1 targeting agents including antibody-drug conjugates., Competing Interests: Competing Interests: Thomas Kryza, Simon Puttick, Yaowu He and John D. Hooper are inventors on a patent covering the use of antibody 10D7 used in this study. No potential conflicts of interest were disclosed by the other authors., (© The author(s).)

Aim: To examine resilience in Science, Technology, Engineering, and Mathematics (STEM) learning within an ecological model, identifying the psychological processes associated with resilient, and non-resilient learning to develop a framework for promoting STEM resilience., Sample and Method: From a sample of secondary-school students (n = 4,936), 1,577 students who found their STEM lesson difficult were identified. Students were assessed on three resilience capabilities and asked to write a commentary on how they responded to the lesson., Results: Factor analysis revealed that resilience in STEM learning could be positioned within the ecological systems model, with students' resilience being comprised of three capabilities; the ability to quickly and easily recover (Recovery), remain focussed on goals (Ecological), and naturally adjust (Adaptive capacity). Using a linguistic analysis programme, we identified the prevalence of words within the student commentaries which related to seven psychological processes. Greater ability to recover was negatively related to negative emotional processes. To increase the specificity of this relationship, we identified high and low resilient students and compared their commentaries. Low resilient students used significantly more anger words. Qualitative analysis revealed interpersonal sources of anger (anger at teacher due to lack of support) and intrapersonal sources of anger (including rumination, expression and control, and seeking distraction)., Conclusions: Anger is a key process that distinguishes students who struggle to recover from a difficult STEM lesson. An ecological systems model may prove useful for understanding STEM resilience and developing intervention pathways. Implications for teacher education include the importance of students' perceptions of teacher support., (© 2022 The Authors. British Journal of Educational Psychology published by John Wiley & Sons Ltd on behalf of British Psychological Society.)

Survival outcomes for patients with glioblastoma multiforme (GBM) have remained poor for the past 15 years, reflecting a clear challenge in the development of more effective treatment strategies. The efficacy of systemic therapies for GBM is greatly limited by the presence of the blood-brain barrier (BBB), which prevents drug penetration and accumulation in regions of infiltrative tumour, as represented in a consistent portion of GBM lesions. Focused ultrasound (FUS) - a technique that uses low-frequency ultrasound waves to induce targeted temporary disruption of the BBB - promises to improve survival outcomes by enhancing drug delivery and accumulation to infiltrating tumour regions. In this review we discuss the current state of preclinical investigations using FUS to enhance delivery of systemic therapies to intracranial neoplasms. We highlight critical methodological inconsistencies that are hampering clinical translation of FUS and we provide guiding principles for future preclinical studies. Particularly, we focus our attention on the importance of the selection of clinically relevant animal models and to the standardization of methods for FUS delivery, which will be paramount to the successful clinical translation of this promising technology for treatment in GBM patients. We also discuss how preclinical FUS research can benefit the development of GBM immunotherapies., (Copyright © 2022. Published by Elsevier B.V.)

Background: Multicentre clinical trials evaluating the role of 18 F-Fluoroethyl-L-tyrosine ( 18 F-FET) PET as a diagnostic biomarker in glioma management have highlighted a need for standardised methods of data analysis. 18 F-FET uptake normalised against background in the contralateral brain is a standard imaging technique to delineate the biological tumour volume (BTV). Quantitative analysis of 18 F-FET PET images requires a consistent and robust background activity. Currently, defining background activity involves the manual selection of an arbitrary region of interest, a process that is subject to large variability. This study aims to eliminate methodological errors in background activity definition through the introduction of a semiautomated method for region of interest selection. A new method for background activity definition, involving the semiautomated generation of mirror-image (MI) reference regions, was compared with the current state-of-the-art method, involving manually drawing crescent-shape (gCS) reference regions. The MI and gCS methods were tested by measuring values of background activity and resulting BTV of 18 F-FET PET scans of ten patients with recurrent glioblastoma multiforme generated from inputs provided by seven readers. To assess intra-reader variability, each scan was evaluated six times by each reader. Intra- and inter-reader variability in background activity and BTV definition was assessed by means of coefficient of variation., Results: Compared to the gCS method, the MI method showed significantly lower intra- and inter-reader variability both in background activity and in BTV definition., Conclusions: The proposed semiautomated MI method minimises intra- and inter-reader variability, providing a valuable approach for standardisation of 18 F-FET PET quantitative parameters. Trial registration ANZCTR, ACTRN12618001346268. Registered 9 August 2018, https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374253., (© 2022. The Author(s).)

Colorectal cancer (CRC) is the third most common malignancy in the world, with 22% of patients presenting with metastatic disease and a further 50% destined to develop metastasis. Molecular imaging uses antigen-specific ligands conjugated to radionuclides to detect and characterise primary cancer and metastases. Expression of the cell surface protein CDCP1 is increased in CRC, and here we sought to assess whether it is a suitable molecular imaging target for the detection of this cancer. CDCP1 expression was assessed in CRC cell lines and a patient-derived xenograft to identify models suitable for evaluation of radio-labelled 10D7, a CDCP1-targeted, high-affinity monoclonal antibody, for preclinical molecular imaging. Positron emission tomography-computed tomography was used to compare zirconium-89 ( 89 Zr)-10D7 avidity to a nonspecific, isotype control 89 Zr-labelled IgG κ 1 antibody. The specificity of CDCP1-avidity was further confirmed using CDCP1 silencing and blocking models. Our data indicate high avidity and specificity for of 89 Zr-10D7 in CDCP1 expressing tumors at. Significantly higher levels than normal organs and blood, with greatest tumor avidity observed at late imaging time points. Furthermore, relatively high avidity is detected in high CDCP1 expressing tumors, with reduced avidity where CDCP1 expression was knocked down or blocked. The study supports CDCP1 as a molecular imaging target for CRC in preclinical PET-CT models using the radioligand 89 Zr-10D7., Competing Interests: Yaowu He, Thomas Kryza, Simon Puttick, and John Hooper are inventors on a Patent Filing for 10D7-based CDCP1-targeted biomolecules., (Copyright © 2021 Tahleesa J. Cuda et al.)

Optimal cytoreduction for ovarian cancer is often challenging because of aggressive tumor biology and advanced stage. It is a critical issue since the extent of residual disease after surgery is the key predictor of ovarian cancer patient survival. For a limited number of cancers, fluorescence-guided surgery has emerged as an effective aid for tumor delineation and effective cytoreduction. The intravenously administered fluorescent agent, most commonly indocyanine green (ICG), accumulates preferentially in tumors, which are visualized under a fluorescent light source to aid surgery. Insufficient tumor specificity has limited the broad application of these agents in surgical oncology including for ovarian cancer. In this study, we developed a novel tumor-selective fluorescent agent by chemically linking ICG to mouse monoclonal antibody 10D7 that specifically recognizes an ovarian cancer-enriched cell surface receptor, CUB-domain-containing protein 1 (CDCP1). 10D7 ICG has high affinity for purified recombinant CDCP1 and CDCP1 that is located on the surface of ovarian cancer cells in vitro and in vivo. Our results show that intravenously administered 10D7 ICG accumulates preferentially in ovarian cancer, permitting visualization of xenograft tumors in mice. The data suggest CDCP1 as a rational target for tumor-specific fluorescence-guided surgery for ovarian cancer.

The implementation of accurate and sensitive molecular detection for the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is paramount to effectively control the ongoing coronavirus disease 2019 (COVID-19) pandemic. In this regard, we herein propose the specific and highly sensitive SARS-CoV-2 detection based on nanoyeast single-chain-variable fragment (scFv) and ultrasensitive plasmonic nanobox-integrated nanomixing microassay. Importantly, this designed platform showcases the utility of nanoyeast-scFvs as specific capture reagents targeting the receptor-binding domain (RBD) of the virus and as monoclonal antibody alternatives suitable for cost-effective mass production and frequent testing. By capitalizing on single-particle active nanoboxes as plasmonic nanostructures for surface-enhanced Raman scattering (SERS), the microassay utilizes highly sensitive Raman signals to indicate virus infection. The developed microassay further integrated nanomixing for accelerating molecular collisions. Through the synergistic working of nanoyeast-scFv, plasmonic nanoboxes, and nanomixing, the highly specific and sensitive SARS-CoV-2 detection is achieved as low as 17 virus/μL without any molecular amplification. We successfully demonstrate SARS-CoV-2 detection in saliva samples of simulated patients at clinically relevant viral loads, suggesting the possibility of this platform for accurate and noninvasive patient screening.

Background: Novel targeted therapies for children diagnosed with medulloblastoma (MB), the most common malignant pediatric brain tumor, are urgently required. A major hurdle in the development of effective therapies is the impaired delivery of systemic therapies to tumor cells due to a specialized endothelial blood-brain barrier (BBB). Accordingly, the integrity of the BBB is an essential consideration in any preclinical model used for assessing novel therapeutics. This study sought to assess the functional integrity of the BBB in several preclinical mouse models of MB., Methods: Dynamic contrast enhancement magnetic resonance imaging (MRI) was used to evaluate blood-brain-tumor barrier (BBTB) permeability in a murine genetically engineered mouse model (GEMM) of Sonic Hedgehog (SHH) MB, patient-derived orthotopic xenograft models of MB (SHH and Gp3), and orthotopic transplantation of GEMM tumor cells, enabling a comparison of the direct effects of transplantation on the integrity of the BBTB. Immunofluorescence analysis was performed to compare the structural and subcellular features of tumor-associated vasculature in all models., Results: Contrast enhancement was observed in all transplantation models of MB. No contrast enhancement was observed in the GEMM despite significant tumor burden. Cellular analysis of BBTB integrity revealed aberrancies in all transplantation models, correlating to the varying levels of BBTB permeability observed by MRI in these models., Conclusions: These results highlight functional differences in the integrity of the BBTB and tumor vessel phenotype between commonly utilized preclinical models of MB, with important implications for the preclinical evaluation of novel therapeutic agents for MB., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

At diagnosis, 22% of colorectal cancer (CRC) patients have metastases, and 50% later develop metastasis. Peptide receptor radionuclide therapy (PRRT), such as 177 Lu-PSMA-617, is used to treat metastatic prostate cancer. 177 Lu-PSMA-617 targets prostate-specific membrane antigen (PSMA), a cell-surface protein enriched in prostate cancer and the neovasculature of other solid tumors, including CRC. We performed 68 Ga-PSMA-11 PET/CT imaging of 10 patients with metastatic CRC to assess metastasis avidity. Eight patients had lesions lacking avidity, and 2 had solitary metastases exhibiting very low avidity. Despite expression of PSMA in CRC neovasculature, none of the patients exhibited tumor avidity sufficient to be considered for 177 Lu-PSMA-617 PRRT., (© 2020 by the Society of Nuclear Medicine and Molecular Imaging.)

Increasing accumulation and retention of nanomedicines within tumor tissue is a significant challenge, particularly in the case of brain tumors where access to the tumor through the vasculature is restricted by the blood-brain barrier (BBB). This makes the application of nanomedicines in neuro-oncology often considered unfeasible, with efficacy limited to regions of significant disease progression and compromised BBB. However, little is understood about how the evolving tumor-brain physiology during disease progression affects the permeability and retention of designer nanomedicines. We report here the development of a modular nanomedicine platform that, when used in conjunction with a unique model of how tumorigenesis affects BBB integrity, allows investigation of how nanomaterial properties affect uptake and retention in brain tissue. By combining different in vivo longitudinal imaging techniques (including positron emission tomography and magnetic resonance imaging), we have evaluated the retention of nanomedicines with predefined physicochemical properties (size and surface functionality) and established a relationship between structure and tissue accumulation as a function of a new parameter that measures BBB leakiness; this offers significant advancements in our ability to relate tumor accumulation of nanomedicines to more physiologically relevant parameters. Our data show that accumulation of nanomedicines in brain tumor tissue is better correlated with the leakiness of the BBB than actual tumor volume . This was evaluated by establishing brain tumors using a spontaneous and endogenously derived glioblastoma model providing a unique opportunity to assess these parameters individually and compare the results across multiple mice. We also quantitatively demonstrate that smaller nanomedicines (20 nm) can indeed cross the BBB and accumulate in tumors at earlier stages of the disease than larger analogues, therefore opening the possibility of developing patient-specific nanoparticle treatment interventions in earlier stages of the disease. Importantly, these results provide a more predictive approach for designing efficacious personalized nanomedicines based on a particular patient's condition., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

The clinical translation of new nanoparticle-based therapies for high-grade glioma (HGG) remains extremely poor. This has partly been due to the lack of suitable preclinical mouse models capable of replicating the complex characteristics of recurrent HGG (rHGG), namely the heterogeneous structural and functional characteristics of the blood-brain barrier (BBB). The goal of this study is to compare the characteristics of the tumor BBB of rHGG with two different mouse models of HGG, the ubiquitously used U87 cell line xenograft model and a patient-derived cell line WK1 xenograft model, in order to assess their suitability for nanomedicine research. Method: Structural MRI was used to assess the extent of BBB opening in mouse models with a fully developed tumor, and dynamic contrast enhanced MRI was used to obtain values of BBB permeability in contrast enhancing tumor. H&E and immunofluorescence staining were used to validate results obtained from the in vivo imaging studies. Results: The extent of BBB disruption and permeability in the contrast enhancing tumor was significantly higher in the U87 model than in rHGG. These values in the WK1 model are similar to those of rHGG. The U87 model is not infiltrative, has an entirely abnormal and leaky vasculature and it is not of glial origin. The WK1 model infiltrates into the non-neoplastic brain parenchyma, it has both regions with intact BBB and regions with leaky BBB and remains of glial origin. Conclusion: The WK1 mouse model more accurately reproduces the extent of BBB disruption, the level of BBB permeability and the histopathological characteristics found in rHGG patients than the U87 mouse model, and is therefore a more clinically relevant model for preclinical evaluations of emerging nanoparticle-based therapies for HGG., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Introduction: Pretargeting strategies that do not rely on the expression of molecular targets have expanded imaging and therapy options for cancer patients. Nanostars with designed multivalency and which highly accumulate in tumor tissue via the enhanced permeability and retention (EPR) effect may therefore be the ideal vectors for the development of a passive pretargeting approach., Methods: Nanostars were synthesized, consisting of 7-8 center-cross-linked arms that were modified with trans-cyclooctene (TCO) using poly(ethylene glycol) (PEG) linkers of 12 or 106 monomer units or without linker. The bioorthogonal click reaction with radiofluorinated 2,2'-(7-(2-(tetrazine-poly(ethyleneglycol) 11 -amino)-2-oxoethyl)-1,4,7-triazonane-1,4-diyl)diacetic acid ([ 18 F]F-Tz-PEG 11 -NODA) or 2,2'-(7-(2-(tetrazine-amino)-2-oxoethyl)-1,4,7-triazonane-1,4-diyl)diacetic acid ([ 18 F]F-Tz-NODA) was measured by ex vivo biodistribution studies and positron emission tomography (PET) in mice bearing tumors with high EPR characteristics. Bioorthogonal masking was performed using a tetrazine-functionalized dextran polymer (Tz-DP)., Results: Highest tumor accumulation of [ 18 F]F-Tz-PEG 11 -NODA was observed for nanostars functionalized with TCO without linker, with a tumor uptake of 3.2 ± 0.4%ID/g and a tumor-to-muscle ratio of 12.8 ± 4.2, tumor-to-large intestine ratio of 0.5 ± 0.3 and tumor-to-kidney ratio of 2.0 ± 0.3, being significantly higher than for nanostars functionalized with TCO-PEG 12 (P < 0.05) or TCO-PEG 106 (P < 0.05). Tumor uptake and tumor-to-tissue ratios did not improve upon bioorthogonal masking with Tz-DP or when using a smaller, more lipophilic tetrazine([ 18 F]F-Tz-NODA)., Conclusions: A pretargeting strategy was developed based on the passive delivery of TCO-functionalized nanostars. Such a strategy would allow for the imaging and treatment of tumors with apparent EPR characteristics, with high radioactive tumor doses and minimal doses to off-target tissues., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: High-grade glioma (HGG) remains a recalcitrant clinical problem despite many decades of research. A major challenge in improving prognosis is the inability of current therapeutic strategies to address a clinically significant burden of infiltrating tumor cells that extend beyond the margins of the primary tumor mass. Such cells cannot be surgically excised nor efficiently targeted by radiation therapy. Therapeutic targeting of this tumor cell population is significantly hampered by the presence of an intact blood-brain barrier (BBB). In this study, we performed a preclinical investigation of the efficiency of MR-guided Focused Ultrasound (FUS) to temporarily disrupt the BBB to allow selective delivery of a tumor-targeting antibody to infiltrating tumor., Methods: Structural MRI, dynamic-contrast enhancement MRI, and histology were used to fully characterize the MR-enhancing properties of a patient-derived xenograft (PDX) orthotopic mouse model of HGG and to develop a reproducible, robust model of nonenhancing HGG. PET-CT imaging techniques were then used to evaluate the efficacy of FUS to increase 89 Zr-radiolabeled antibody concentration in nonenhancing HGG regions and adjacent non-targeted tumor tissue., Results: The PDX mouse model of HGG has a significant tumor burden lying behind an intact BBB. Increased antibody uptake in nonenhancing tumor regions is directly proportional to the FUS-targeted volume. FUS locally increased antibody uptake in FUS-targeted regions of the tumor with an intact BBB, while leaving untargeted regions unaffected., Conclusions: FUS exposure successfully allowed temporary BBB disruption, localized to specifically targeted, nonenhancing, infiltrating tumor regions and delivery of a systemically administered antibody was significantly increased., (© The Author(s) 2020. Published by Oxford University Press, the Society for Neuro-Oncology and the European Association of Neuro-Oncology.)

Background : CUB domain-containing protein 1 (CDCP1) is a cell surface receptor regulating key signalling pathways in malignant cells. CDCP1 has been proposed as a molecular target to abrogate oncogenic signalling pathways and specifically deliver anti-cancer agents to tumors. However, the development of CDCP1-targeting agents has been questioned by its frequent proteolytic processing which was thought to result in shedding of the CDCP1 extracellular domain limiting its targetability. In this study, we investigated the relevance of targeting CDCP1 in the context of pancreatic ductal adenocarcinoma (PDAC) and assess the impact of CDCP1 proteolysis on the effectiveness of CDCP1 targeting agents. Methods : The involvement of CDCP1 in PDAC progression was assessed by association analysis in several PDAC cohorts and the proteolytic processing of CDCP1 was evaluated in PDAC cell lines and patient-derived cells. The consequences of CDCP1 proteolysis on its targetability in PDAC cells was assessed using immunoprecipitation, immunostaining and biochemical assays. The involvement of CDCP1 in PDAC progression was examined by loss-of-function in vitro and in vivo experiments employing PDAC cells expressing intact or cleaved CDCP1. Finally, we generated antibody-based imaging and therapeutic agents targeting CDCP1 to demonstrate the feasibility of targeting this receptor for detection and treatment of PDAC tumors. Results : High CDCP1 expression in PDAC is significantly associated with poorer patient survival. In PDAC cells proteolysis of CDCP1 does not always result in the shedding of CDCP1-extracellular domain which can interact with membrane-bound CDCP1 allowing signal transduction between the different CDCP1-fragments. Targeting CDCP1 impairs PDAC cell functions and PDAC tumor growth independently of CDCP1 cleavage status. A CDCP1-targeting antibody is highly effective at delivering imaging radionuclides and cytotoxins to PDAC cells allowing specific detection of tumors by PET/CT imaging and superior anti-tumor effects compared to gemcitabine in in vivo models. Conclusion : Independent of its cleavage status, CDCP1 exerts oncogenic functions in PDAC and has significant potential to be targeted for improved radiological staging and treatment of this cancer. Its elevated expression by most PDAC tumors and lack of expression by normal pancreas and other major organs, suggest that targeting CDCP1 could benefit a significant proportion of PDAC patients. These data support the further development of CDCP1-targeting agents as personalizable tools for effective imaging and treatment of PDAC., Competing Interests: Competing Interests: Thomas Kryza, Tashbib Khan, Simon Puttick, Tahleesa Cuda, Elena I Deryugina, James P. Quigley, Yaowu He and John D. Hooper are inventors on a patent that includes monoclonal antibody 10D7 used in this study. No potential conflicts of interest were disclosed by the other authors., (© The author(s).)

CUB-domain containing protein 1 (CDCP1) is a cancer associated cell surface protein that amplifies pro-tumorigenic signalling by other receptors including EGFR and HER2. Its potential as a cancer target is supported by studies showing that anti-CDCP1 antibodies inhibit cell migration and survival in vitro , and tumor growth and metastasis in vivo . Here we characterize two anti-CDCP1 antibodies, focusing on immuno-conjugates of one of these as a tool to detect and inhibit ovarian cancer. Methods : A panel of ovarian cancer cell lines was examined for cell surface expression of CDCP1 and loss of expression induced by anti-CDCP1 antibodies 10D7 and 41-2 using flow cytometry and Western blot analysis. Surface plasmon resonance analysis and examination of truncation mutants was used to analyse the binding properties of the antibodies for CDCP1. Live-cell spinning-disk confocal microscopy of GFP-tagged CDCP1 was used to track internalization and intracellular trafficking of CDCP1/antibody complexes. In vivo , zirconium 89-labelled 10D7 was detected by positron-emission tomography imaging, of an ovarian cancer patient-derived xenograft grown intraperitoneally in mice. The efficacy of cytotoxin-conjugated 10D7 was examined against ovarian cancer cells in vitro and in vivo . Results : Our data indicate that each antibody binds with high affinity to the extracellular domain of CDCP1 causing rapid internalization of the receptor/antibody complex and degradation of CDCP1 via processes mediated by the kinase Src. Highlighting the potential clinical utility of CDCP1, positron-emission tomography imaging, using zirconium 89-labelled 10D7, was able to detect subcutaneous and intraperitoneal xenograft ovarian cancers in mice, including small (diameter <3 mm) tumor deposits of an ovarian cancer patient-derived xenograft grown intraperitoneally in mice. Furthermore, cytotoxin-conjugated 10D7 was effective at inhibiting growth of CDCP1-expressing ovarian cancer cells in vitro and in vivo . Conclusions : These data demonstrate that CDCP1 internalizing antibodies have potential for killing and detection of CDCP1 expressing ovarian cancer cells., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

Expression levels of biomarkers are generally unknown at initial diagnosis. The development of theranostic probes that do not rely on biomarker availability would expand therapy options for cancer patients, improve patient selection for nanomedicine and facilitate treatment of inoperable patients or patients with acquired therapy resistance. Herein, we report the development of star polymers, also known as nanostars, that allow for molecular imaging and/or endoradiotherapy based on passive targeting via the enhanced permeability and retention (EPR) effect. Methods: We synthesised a star copolymer, consisting of 7-8 centre-cross-linked arms that were modified with Gd 3+ for magnetic resonance imaging (MRI), and functionalised either with 89 Zr for in vivo quantification and positron emission tomography (PET) imaging, or with 177 Lu for endoradiotherapy. 1 H longitudinal relaxivities were determined over a continuum of magnetic field strengths ranging from 0.24 mT - 0.94 T at 37 °C (nuclear magnetic relaxation dispersion (NMRD) profile) and T 1 -weighted MRI contrast enhancement was visualized at 3 T and 7 T. PET imaging and ex vivo biodistribution studies were performed in mice bearing tumours with high EPR (CT26) or low EPR (BxPC3) characteristics. Therapy studies were performed in mice with high EPR tumours and mean absorbed organ doses were estimated for a standard human model. Results: The star copolymer with Gd 3+ = 0.60 s) compared to the standard clinical contrast agent Gadovist ( T = 1.0 s). Quantification of tumour accumulation using the radiolabelled nanostars in tumour-bearing mice demonstrated an exceptionally high uptake in tumours with high EPR characteristics (14.8 - 21.7 %ID/g). Uptake of the star polymers in tumours with low EPR characteristics was significantly lower ( 1 = 0.60 s) compared to the standard clinical contrast agent Gadovist ( T 1 = 1.0 s). Quantification of tumour accumulation using the radiolabelled nanostars in tumour-bearing mice demonstrated an exceptionally high uptake in tumours with high EPR characteristics (14.8 - 21.7 %ID/g). Uptake of the star polymers in tumours with low EPR characteristics was significantly lower ( P <0.001), suggesting passive tumour accumulation of the nanostars via the EPR effect. Survival of mice treated with high dose 177 Lu-labelled star polymers was significantly higher than survival of mice treated with lower therapy doses or control mice ( P =0.001), demonstrating the utility of the 177 Lu-labelled star polymers as platforms for endoradiotherapy. Conclusion: Our work highlights the potential of star polymers as probes for the molecular imaging of cancer tissue or for the passive delivery of radionuclides for endoradiotherapy. Their high functionalisability and high tumour accumulation emphasises their versatility as powerful tools for nanomedicine., Competing Interests: Competing Interests: The authors have declared that no competing interest exists., (© The author(s).)

The functionalization of proteins with different cargo molecules is highly desirable for a broad range of applications. However, the reproducible production of defined conjugates with multiple functionalities is a significant challenge. Herein, we report the dual site-specific labeling of an antibody fragment, utilizing the orthogonal Sortase A and π-clamp conjugation methods, and demonstrate that binding of the antibody fragment to its target receptor is retained after dual labeling.

Metal shell microcapsules have been shown to completely retain their core until its release is triggered, making them a promising candidate for use as a controllable drug delivery vehicle due to their superior retention properties as compared to polymer shell microcapsules. Focused ultrasound (FUS) has been successfully utilised to trigger release of lipophilic drugs from polymer microcapsules, and in this work the response of gold shell microcapsules with and without an inner polymeric shell, to FUS and standard ultrasound is explored. The results show that gold shell microcapsules with an inner polymer shell rupture when exposed to standard ultrasound and that there is a linear correlation between the gold shell thickness and the extent of shell rupture. When FUS is applied to these microcapsules, powers as low as 0.16 W delivered in bursts of 10 ms/s over a period of 120 s are sufficient to cause rupture of 53 nm gold shell microcapsules. Additional findings suggest that gold shell microcapsules without the polymer layer dispersed in a hydrogel matrix, as opposed to aqueous media, rupture more efficiently when exposed to FUS, and that thicker gold shells are more responsive to ultrasound-triggered rupture regardless of the external environment. Release of dye from all successfully ruptured capsules was sustained over a period of between 7 and 35 days. These findings suggest that emulsion-templated gold shell microcapsules embedded in a hydrogel matrix would be suitable for use as an implantable drug delivery vehicle with FUS used to externally trigger release., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Brain metastases are the most prevalent of intracranial malignancies. They are associated with a very poor prognosis and near 100% mortality. This has been the case for decades, largely because we lack effective therapeutics to augment surgery and radiotherapy. Notwithstanding improvements in the precision and efficacy of these life-prolonging treatments, with no reliable options for adjunct systemic therapy, brain recurrences are virtually inevitable. The factors limiting intracranial efficacy of existing agents are both physiological and molecular in nature. For example, heterogeneous permeability, abnormal perfusion and high interstitial pressure oppose the conventional convective delivery of circulating drugs, thus new delivery strategies are needed to achieve uniform drug uptake at therapeutic concentrations. Brain metastases are also highly adapted to their microenvironment, with complex cross-talk between the tumor, the stroma and the neural compartments driving speciation and drug resistance. New strategies must account for resistance mechanisms that are frequently engaged in this milieu, such as HER3 and other receptor tyrosine kinases that become induced and activated in the brain microenvironment. Here, we discuss molecular and physiological factors that contribute to the recalcitrance of these tumors, and review emerging therapeutic strategies, including agents targeting the PI3K axis, immunotherapies, nanomedicines and MRI-guided focused ultrasound for externally controlling drug delivery.

The EphA3 receptor has recently emerged as a functional tumour-specific therapeutic target in glioblastoma (GBM). EphA3 is significantly elevated in recurrent disease, is most highly expressed on glioma stem cells (GSCs), and has a functional role in maintaining self-renewal and tumourigenesis. An unlabelled EphA3-targeting therapeutic antibody is currently under clinical assessment in recurrent GBM patients. In this study, we assessed the efficacy of EphA3 antibody drug conjugate (ADC) and radioimmunotherapy (RIT) approaches using orthotopic animal xenograft models. Brain uptake studies, using positron emission tomography/computed tomography (PET/CT) imaging, show EphA3 antibodies are effectively delivered across the blood-tumour barrier and accumulate at the tumour site with no observed normal brain reactivity. A robust anti-tumour response, with no toxicity, was observed using EphA3, ADC, and RIT approaches, leading to a significant increase in overall survival. Our current research provides evidence that GBM patients may benefit from pay-loaded EphA3 antibody therapies.

Despite significant improvements in the clinical management of glioblastoma, poor delivery of systemic therapies to the entire population of tumour cells remains one of the biggest challenges in the achievement of more effective treatments. On the one hand, the abnormal and dysfunctional tumour vascular network largely limits blood perfusion, resulting in an inhomogeneous delivery of drugs to the tumour. On the other hand, the presence of an intact blood-brain barrier (BBB) in certain regions of the tumour prevents chemotherapeutic drugs from permeating through the tumour vessels and reaching the diseased cells. In this review we analyse in detail the implications of the presence of a dysfunctional vascular network and the impenetrable BBB on drug transport. We discuss advantages and limitations of the currently available strategies for remodelling the tumour vasculature aiming to ameliorate the above mentioned limitations. Finally we review research methods for visualising vascular dysfunction and highlight the power of DCE- and DSC-MRI imaging to assess changes in blood perfusion and BBB permeability., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The encapsulation of small molecule drugs in nanomaterials has become an increasingly popular approach to the delivery of therapeutics. The use of emulsions as templates for the synthesis of drug impregnated nanomaterials is an exciting area of research, and a great deal of progress has been made in understanding the interfacial chemistry that is critical to controlling the physicochemical properties of both the encapsulated material and the templated material. For example, control of the interfacial tension between an oil and aqueous phase is a fundamental concern when designing drug delivery vehicles that are stabilized by particulate surfactants at the fluid interface. Particles in general are capable of self-assembly at a fluid interface, with a preference for one or the other of the phases, and much work has focussed on modification of the particle properties to optimize formation and stability of the emulsion. An issue arises however when a model, single oil system is translated into more complex, real-world scenarios, which are often multi-component, with the incorporation of charged active ingredients and other excipients. The result is potentially a huge change in the properties of the dispersed phase which can lead to a failure in the capability of particles to continue to stabilize the interface. In this mini-review, we will focus on two encapsulation strategies based on the selective deposition of particles or proteins on a fluid-fluid interface: virus-like particles and polymer microcapsules formed from particle-stabilized emulsion templates. The similarity between these colloidal systems lies in the fact that particulate entities are used to stabilize fluid cores. We will focus on those studies that have described the effect of subtle changes in core composition on the self-assembly of particles at the fluid-fluid interface and how this influences the resulting capsule structure.

Thermal decomposition (TD) products of the ionic liquids (ILs) [CnC1Im][BF4] and [CnC1Im][PF6] ([CnC1Im]+ = 1-alkyl-3-methylimidazolium, [BF4]- = tetrafluoroborate, and [PF6]- = hexafluorophosphate) were prepared, ex situ, by bulk heating experiments in a bespoke setup. The respective products, CnC1(C3N2H2)BF3 and CnC1(C3N2H2)PF5 (1-alkyl-3-methylimidazolium-2-trifluoroborate and 1-alkyl-3-methylimidazolium-2-pentafluorophosphate), were then vaporized and analyzed by direct insertion mass spectrometry (DIMS) in order to identify their characteristic MS signals. During IL DIMS experiments we were subsequently able, in situ, to identify and monitor signals due to both IL vaporization and IL thermal decomposition. These decomposition products have not been observed in situ during previous analytical vaporization studies of similar ILs. The ex situ preparation of TD products is therefore perfectly complimentary to in situ thermal stability measurements. Experimental parameters such as sample surface area to volume ratios are consequently very important for ILs that show competitive vaporization and thermal decomposition. We have explained these experimental factors in terms of Langmuir evaporation and Knudsen effusion-like conditions, allowing us to draw together observations from previous studies to make sense of the literature on IL thermal stability. Hence, the design of experimental setups are crucial and previously overlooked experimental factors.

There is currently intense interest in new methods for understanding the fate of therapeutically-relevant cells, such as mesenchymal stem cells (MSCs). The absence of a confounding background signal and consequent unequivocal assignment makes 19F MRI one of the most attractive modalities for the tracking of injected cells in vivo. We describe here the synthesis of novel partly-fluorinated polymeric nanoparticles with small size and high fluorine content as MRI agents. The polymers, constructed from perfluoropolyether methacrylate (PFPEMA) and oligo(ethylene glycol) methacrylate (OEGMA) have favourable cell uptake profiles and excellent MRI performance. To facilitate cell studies the polymer was further conjugated with a fluorescent dye creating a dual-modal imaging agent. The efficacy of labelling of MSCs was assessed using 19F NMR, flow cytometry and confocal microscopy. The labelling efficiency of 2.6 ± 0.1 × 1012 19F atoms per cell, and viability of >90% demonstrates high uptake and good tolerance by the cells. This loading translates to a minimum 19F MRI detection sensitivity of ∼7.4 × 103 cells per voxel. Importantly, preliminary in vivo data demonstrate that labelled cells can be readily detected within a short acquisition scan period (12 minutes). Hence, these copolymers show outstanding potential for 19F MRI cellular tracking and for quantification of non-phagocytic and therapeutically-relevant cells in vivo.

Metal microcapsules have recently received attention and are being developed as improved carrier materials when compared to polymer microcapsules. In this work we have developed a novel, simplified method by which polymeric microcapsules can be synthesised using a combination of poly(vinyl pyrrolidone)-stabilised platinum nanoparticles (PVP-Pt) and poly(vinyl pyrrolidone) (PVP) as stabilisers, to allow for a secondary metal shell to be grown. We investigate the relationship between the molar ratio of reducing agent to platinum salt and the size of the resulting NPs and seek to develop further fundamental understanding of the factors governing the secondary metal shell thickness and quality, to allow production of cost-effective metal microcapsules without sacrificing core retention efficiency. We found that the size of the nanoparticles had no significant effect on secondary shell thickness, but did affect the quality of the resulting gold shells. Gold salt concentration was found to be a limiting factor in the electroless deposition of the metal shell. In this work, we have successfully produced PLGA microcapsules with more cost-effective gold shells, as thin as 56 ± 13 nm and capable of complete core retention of volatile actives.

Continuing our research efforts in developing mesoporous silicon nanoparticle-based biomaterials for cancer therapy, we employed here porous silicon nanoparticles as a nanocarrier to deliver contrast agents to diseased cells. Nanoconfinement of small molecule Gd-chelates (L1-Gd) enhanced the T 1 contrast dramatically compared to distinct Gd-chelate (L1-Gd) by virtue of its slow tumbling rate, increased number of bound water molecules, and their occupancy time. The newly synthesized Gd-chelate (L1-Gd) was covalently grafted on silicon nanostructures and conjugated to an antibody specific for epidermal growth factor receptor (EGFR) via a hydrazone linkage. The salient feature of this nanosized contrast agent is the capability of EGFR targeted delivery to cancer cells. Mesoporous silicon nanoparticles were chosen as the nanocarrier because of their high porosity, high surface area, and excellent biodegradability. This type of nanosized contrast agent also performs well in high magnetic fields.

Imaging using more than one biological process using PET could be of great utility, but despite previously proposed approaches to dual-tracer imaging, it is seldom performed. The alternative of performing multiple scans is often infeasible for clinical practice or even in research studies. Dual-tracer PET scanning allows for multiple PET radiotracers to be imaged within the same imaging session. In this paper we describe our approach to utilise the basis pursuit method to aid in the design of dual-tracer PET imaging experiments, and later in separation of the signals. The advantage of this approach is that it does not require a compartment model architecture to be specified or even that both signals are distinguishable in all cases. This means the method for separating dual-tracer signals can be used for many feasible and useful combinations of biology or radiotracer, once an appropriate scanning protocol has been decided upon. Following a demonstration in separating the signals from two consecutively injected radionuclides in a controlled experiment, phantom and list-mode mouse experiments demonstrated the ability to test the feasibility of dual-tracer imaging protocols for multiple injection delays. Increases in variances predicted for kinetic macro-parameters V D and K I in brain and tumoral tissue were obtained when separating the synthetically combined data. These experiments confirmed previous work using other approaches that injections delays of 10-20 min ensured increases in variance were kept minimal for the test tracers used. On this basis, an actual dual-tracer experiment using a 20 min delay was performed using these radio tracers, with the kinetic parameters (V D and K I ) extracted for each tracer in agreement with the literature. This study supports previous work that dual-tracer PET imaging can be accomplished provided certain constraints are adhered to. The utilisation of basis pursuit techniques, with its removed need to specify a model architecture, allows the feasibility of a range of imaging protocols to be investigated via simulation in a straight-forward manner for a wide range of possible scenarios. The hope is that the ease of utilising this approach during feasibility studies and in practice removes any perceived technical barrier to performing dual-tracer imaging.

Positron Emission Tomography (PET) data is intrinsically dynamic, and kinetic analysis of dynamic PET data can substantially augment the information provided by static PET reconstructions. Yet despite the insights into disease that kinetic analysis offers, it is not used clinically and seldom used in research beyond the preclinical stage. The utility of PET kinetic analysis is hampered by several factors including spatial inconsistency within regions of homogeneous tissue and relative computational expense when fitting complex models to individual voxels. Even with sophisticated algorithms inconsistencies can arise because local optima frequently have narrow basins of convergence, are surrounded by relatively flat (uninformative) regions, have relatively low-gradient valley floors, or combinations thereof. Based on the observation that cost functions for individual voxels frequently bear some resemblance to each-other, this paper proposes the federated optimisation of the individual kinetic analysis problems within a given image. This approach shares parameters proposed during optimisation with other, similar voxels. Federated optimisation exploits the redundancy typical of large medical images to improve the optimisation residuals, computational efficiency and, to a limited extent, image consistency. This is achieved without restricting the formulation of the kinetic model, resorting to an explicit regularisation parameter, or limiting the resolution at which parameters are computed., (Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.)

Introduction: Despite radical treatment therapies, glioma continues to carry with it a uniformly poor prognosis. Patients diagnosed with WHO Grade IV glioma (glioblastomas; GBM) generally succumb within two years, even those with WHO Grade III anaplastic gliomas and WHO Grade II gliomas carry prognoses of 2-5 and 2 years, respectively. PET imaging with (18)F-FDOPA allows in vivo assessment of the metabolism of glioma relative to surrounding tissues. The high sensitivity of (18)F-DOPA imaging grants utility for a number of clinical applications., Methods: A collection of published work about (18)F-FDOPA PET was made and a critical review was discussed and written., Results: A number of research papers have been published demonstrating that in conjunction with MRI, (18)F-FDOPA PET provides greater sensitivity and specificity than these modalities in detection, grading, prognosis and validation of treatment success in both primary and recurrent gliomas. In further comparisons with (11)C-MET, (18)F-FLT, (18)F-FET and MRI, (18)F-FDOPA has shown similar or better efficacy. Recently synthesis cassettes have become available, making (18)F-FDOPA more accessible., Conclusions: According to the available data, (18)F-FDOPA PET is a viable radiotracer for imaging and treatment planning of gliomas., Advances in Knowledge and Implication for Patient Care: (18)F-FDOPA PET appears to be a viable radiopharmaceutical for the diagnosis and treatment planning of gliomas cases, improving on that of MRI and (18)F-FDG PET., (Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.)

Highly branched polymers are a promising platform for the design of next-generation contrast agents for (19)F magnetic resonance imaging (MRI). A series of segmented highly branched polymers (SHBPs) consisting of fluoro- and PEG-based monomers were synthesized by self-condensing vinyl copolymerization (SCVP) using the reversible addition-fragmentation chain transfer (RAFT) technique. SHBPs having different compositions and degrees of branching were obtained by varying the monomer type and feed ratio of monomer to chain transfer agent (CTA). The chemical structures and physical properties of the branched polymers were thoroughly characterized in detail by NMR, SEC and DSC. The systematic variation in structural parameters allowed the relationships between molecular structure, sequence distribution, and imaging performance to be examined. The (19)F NMR properties were strongly affected by the sequence distribution of the fluorinated monomers, the type of polymer backbone and the degree of branching. As a result, SHBPs consisting of statistical copolymeric segments of acrylate units were identified as excellent candidates for imaging due to a single (19)F signal, long T2 relaxation times, and high fluorine contents. The SHBPs could be all imaged or selectively imaged by taking advantage of the differences in relaxation times, demonstrating tunable and selective imaging performance through tailoring the structure and composition of the SHBPs.

Glioma is the most aggressive brain tumour, resulting in death often within 1-2 years. Current treatment strategies involve surgical resection followed by chemoradiation therapy. Despite continuing improvements in the delivery of adjuvant therapies, there has not been a dramatic increase in survival for glioma. Molecular imaging techniques have become central in the development of new therapeutic strategies in recent years. The multimodal imaging technology of positron emission tomography/magnetic resonance imaging (PET/MRI) has recently been realised on a preclinical scale and the effect of this technology is starting to be observed in preclinical drug development for glioma. Here, we propose that PET/MRI will play an integral part in the development of new diagnostic and therapeutic strategies for glioma., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

There is significant interest in the development of improved image-guided therapy for neuro-oncology applications. Glioblastomas (GBM) in particular present a considerable challenge because of their pervasive nature, propensity for recurrence, and resistance to conventional therapies. MRI is routinely used as a guide for planning treatment strategies. However, this imaging modality is not able to provide images that clearly delineate tumor boundaries and affords only indirect information about key tumor pathophysiology. With the emergence of PET imaging with new oncology radiotracers, mapping of tumor infiltration and other important molecular events such as hypoxia is now feasible within the clinical setting. In particular, the importance of imaging hypoxia levels within the tumoral microenvironment is gathering interest, as hypoxia is known to play a central role in glioma pathogenesis and resistance to treatment. One of the hypoxia radiotracers known for its clinical utility is (18)F-fluoromisodazole ((18)F-FMISO). In this review, we highlight the typical causes of treatment failure in gliomas that may be linked to hypoxia and outline current methods for the detection of hypoxia. We also provide an overview of the growing body of studies focusing on the clinical translation of (18)F-FMISO PET imaging, strengthening the argument for the use of (18)F-FMISO hypoxia imaging to help optimize and guide treatment strategies for patients with glioblastoma., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Noninvasive imaging is a critical technology for diagnosis, classification, and subsequent treatment planning for patients with glioblastoma. It has been shown that the EphA2 receptor tyrosine kinase (RTK) is overexpressed in a number of tumors, including glioblastoma. Expression levels of Eph RTKs have been linked to tumor progression, metastatic spread, and poor patient prognosis. As EphA2 is expressed at low levels in normal neural tissues, this protein represents an attractive imaging target for delineation of tumor infiltration, providing an improved platform for image-guided therapy. In this study, EphA2-4B3, a monoclonal antibody specific to human EphA2, was labeled with 64Cu through conjugation to the chelator 1,4,7-triazacyclononane-1,4,7-triacetic acid (NOTA). The resulting complex was used as a positron emission tomography (PET) tracer for the acquisition of high-resolution longitudinal PET/magnetic resonance images. EphA2-4B3-NOTA-64Cu images were qualitatively and quantitatively compared to the current clinical standards of [18F]FDOPA and gadolinium (Gd) contrast-enhanced MRI. We show that EphA2-4B3-NOTA-64Cu effectively delineates tumor boundaries in three different mouse models of glioblastoma. Tumor to brain contrast is significantly higher in EphA2-4B3-NOTA-64Cu images than in [18F]FDOPA images and Gd contrast-enhanced MRI. Furthermore, we show that nonspecific uptake in the liver and spleen can be effectively blocked by a dose of nonspecific (isotype control) IgG.