Combining in Vitro Diagnostics with in Vivo Imaging for Earlier Detection of Pancreatic Ductal Adenocarcinoma: Challenges and Solutions

Early features of pancreatic cancer on magnetic resonance imaging (MRI): a case-control study

PURPOSE

Magnetic resonance imaging has been recommended as a primary imaging modality among high-risk individuals undergoing screening for pancreatic cancer. We aimed to delineate potential precursor lesions for pancreatic cancer on MR imaging.

METHODS

We conducted a case-control study at Kaiser Permanente Southern California (2008-2018) among patients that developed pancreatic cancer who had pre-diagnostic MRI examinations obtained 2-36 months prior to cancer diagnosis (cases) matched 1:2 by age, gender, race/ethnicity, contrast status and year of scan (controls). Patients with history of acute/chronic pancreatitis or prior pancreatic surgery were excluded. Images underwent blind review with assessment of a priori defined series of parenchymal and ductal features. We performed logistic regression to assess the associations between individual factors and pancreatic cancer. We further assessed the interaction among features as well as performed a sensitivity analysis stratifying based on specific time-windows (2-3 months, 4-12 months, 13-36 months prior to cancer diagnosis).

RESULTS

We identified 141 cases (37.9% stage I-II, 2.1% III, 31.4% IV, 28.6% unknown) and 292 matched controls. A solid mass was noted in 24 (17%) of the pre-diagnostic MRI scans. Compared to controls, pre-diagnostic images from cancer cases more frequently exhibited the following ductal findings: main duct dilatation (51.4% vs 14.3%, OR [95% CI]: 7.75 [4.19-15.44], focal pancreatic duct stricture with distal (upstream) dilatation (43.6% vs 5.6%, OR 12.71 [6.02-30.89], irregularity (42.1% vs 6.0%, OR 9.73 [4.91-21.43]), focal pancreatic side branch dilation (13.6% vs1.6%, OR 11.57 [3.38-61.32]) as well as parenchymal features: atrophy (57.9% vs 27.4%, OR 46.4 [2.71-8.28], focal area of signal abnormality (39.3% vs 4.8%, OR 15.69 [6.72-44,78]), all p < 0.001).

CONCLUSION

In addition to potential missed lesions, we have identified a series of ductal and parenchymal features on MRI that are associated with increased odds of developing pancreatic cancer.

Selection of potential targets for stratifying congenital pulmonary airway malformation patients with molecular imaging: is MUC1 the one?

Currently there is a global lack of consensus about the best treatment for asymptomatic congenital pulmonary airway malformation (CPAM) patients. The somatic KRAS mutations commonly found in adult lung cancer combined with mucinous proliferations are sometimes found in CPAM. For this risk of developing malignancy, 70% of paediatric surgeons perform a resection for asymptomatic CPAM. In order to stratify these patients into high- and low-risk groups for developing malignancy, a minimally invasive diagnostic method is needed, for example targeted molecular imaging. A prerequisite for this technique is a cell membrane bound target. The aim of this study was to review the literature to identify potential targets for molecular imaging in CPAM patients and perform a first step to validate these findings.A systematic search was conducted to identify possible targets in CPAM and adenocarcinoma in situ (AIS) patients. The most interesting targets were evaluated with immunofluorescent staining in adjacent lung tissue, KRAS+ CPAM tissue and KRAS- CPAM tissue.In 185 included studies, 143 possible targets were described, of which 20 targets were upregulated and membrane-bound. Six of them were also upregulated in lung AIS tissue (CEACAM5, E-cadherin, EGFR, ERBB2, ITGA2 and MUC1) and as such of possible interest. Validating studies showed that MUC1 is a potential interesting target.This study provides an extensive overview of all known potential targets in CPAM that might identify those patients at risk for malignancy and conducted the first step towards validation, identifying MUC1 as the most promising target.

Surgical Diagnoses of Pancreatic Adenocarcinoma Not Found on Previous Endoscopic Ultrasound: A Case Series and Review of the Literature

INTRODUCTION

Pancreatic cancer is a leading cause of death in North America and Western Europe with rising rates in the developing world. Endoscopic ultrasound (EUS) with FNA (fine needle aspiration) is a critical component in the evaluation and diagnosis of pancreatic lesions with a high sensitivity and specificity. In this paper, we report patients at our center who eventually developed pancreatic cancer despite an early negative EUS, and identifying factors that may result in a missed diagnosis.

METHODS

The University of Louisville database was queried for patients who had a Whipple procedure for presumed benign disease and had a pre-operative EUS between 2008 and 2018. Patients who had pancreatic adenocarcinoma on final pathology were identified. Demographic, clinical, EUS, operative, and pathologic details were reviewed for each case in efforts to identify factors associated with failure to diagnose a pancreatic malignancy on EUS.

RESULTS

Five patients who had pancreatic adenocarcinoma on final pathology were reviewed in detail and their cases are presented in the paper. Four of the patients had dilation of the common bile duct, three had chronic pancreatitis. Two of them had previous surgery on the pancreas or bile ducts.

CONCLUSIONS

All of the patients presented in the paper had variables that made their EUS evaluation challenging. A high index of suspicion must be maintained in patients that do not improve after appropriate treatment of their strictures or pancreatic lesions. In the future, new techniques, such as fine needle biopsy and biomarker assays, may improve diagnosis accuracy.

Biomarkers for pancreatic cancer based on tissue and serum metabolomics analysis in a multicenter study

BACKGROUND

Early detection of pancreatic ductal adenocarcinoma (PDAC) may improve the prognosis of patients. This study was to identify metabolic features of PDAC and to discover early detection biomarkers for PDAC by tissue and serum metabolomics analysis.

METHODS

We conducted nontargeted metabolomics analysis in tissue samples of 51 PDAC tumors, 40 noncancerous pancreatic tissues (NT), and 14 benign pancreatic neoplasms (BP) as well as serum samples from 80 patients with PDAC, 36 with BP, and 48 healthy controls (Ctr). The candidate metabolites identified from the initial analysis were further quantified using targeted analysis in serum samples of an independent cohort of 22 early stage PDAC, 27 BP, and 27 Ctr subjects. Unconditional binary logistic regression analysis was used to construct the optimal model for PDAC diagnosis.

RESULTS

Upregulated levels of fatty acids and lipids and downregulated amino acids were observed in tissue and serum samples of PDAC patients. Proline, creatine, and palmitic acid were identified as a panel of potential biomarkers to distinguish PDAC from BP and Ctr (odds ratio = 2.17, [95% confidence interval 1.34-3.53]). The three markers showed area under the receiver-operating characteristic curves (AUCs) of 0.854 and 0.865, respectively, for the comparison of PDAC versus Ctr and PDAC versus BP. The AUCs were 0.830 and 0.852 in the validation set and were improved to 0.949 and 0.909 when serum carbohydrate antigen 19-9 (CA19-9) was added to the model.

CONCLUSION

The novel metabolite biomarker panel identified in this study exhibited promising performance in distinguishing PDAC from BP or Ctr, especially in combination with CA19-9.

Recent advances in understanding pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an intractable cancer and a leading cause of cancer deaths worldwide. Over 90% of patients die within 1 year of diagnosis. Deaths from PDAC are increasing and it remains a cancer of substantial unmet need. A number of factors contribute to its poor prognosis: namely, late presentation, early metastases and limited systemic therapy options because of chemoresistance. A variety of research approaches underway are aimed at improving patient survival. Here, we review high-risk groups and efforts for early detection. We examine recent developments in the understanding of complex molecular and metabolic alterations which accompany PDAC. We explore artificial intelligence and biological targets for therapy and examine the role of tumour stroma and the immune microenvironment. We also review recent developments with respect to the PDAC microbiome. It is hoped that current research efforts will translate into earlier diagnosis, improvements in treatment and better outcomes for patients.

ImmunoPET/NIRF/Cerenkov multimodality imaging of ICAM-1 in pancreatic ductal adenocarcinoma

PURPOSE

We dual-labeled an intercellular adhesion molecule-1 (ICAM-1) monoclonal antibody (mAb) and evaluated its effectiveness for lesion detection and surgical navigation in pancreatic ductal adenocarcinoma (PDAC) via multiple noninvasive imaging approaches, including positron emission tomography (PET), near-infrared fluorescence (NIRF), and Cerenkov luminescence imaging (CLI).

METHODS

ICAM-1 expression in PDAC cell lines (BxPC-3 and AsPC-1) was assessed via flow cytometry and immunofluorescent staining. An ICAM-1 mAb labeled by IRDye 800CW and radionuclide zirconium-89 (denoted as [⁸⁹Zr]Zr-DFO-ICAM-1-IR800) was synthesized. Its performance was validated via in vivo comparative PET/NIRF/CLI and biodistribution (Bio-D) studies in nude mice bearing subcutaneous BxPC-3/AsPC-1 tumors or orthotopic BxPC-3 tumor models using nonspecific IgG as an isotype control tracer.

RESULTS

ICAM-1 expression was strong in the BxPC-3 and minimal in the AsPC-1 cell line. Both multimodality imaging and Bio-D data exhibited more prominent uptake of [⁸⁹Zr]Zr-DFO-ICAM-1-IR800 in BxPC-3 tumors than in AsPC-1 tumors. The uptake of [⁸⁹Zr]Zr-DFO-IgG-IR800 in BxPC-3 tumors was similar to that of [⁸⁹Zr]Zr-DFO-ICAM-1-IR800 in AsPC-1 tumors. These results demonstrate the desirable affinity and specificity of [⁸⁹Zr]Zr-DFO-ICAM-1-IR800 compared to [⁸⁹Zr]Zr-DFO-IgG-IR800. Orthotopic BxPC-3 tumor foci could also be clearly delineated by [⁸⁹Zr]Zr-DFO-ICAM-1-IR800. An intermodal match was achieved in the ICAM-1-targeted immunoPET/NIRF/CLI. The positive expression levels of ICAM-1 in BxPC-3 tumor tissue were further confirmed by immunohistopathology.

CONCLUSION

We successfully developed a dual-labeled ICAM-1-targeted tracer for PET/NIRF/CLI of PDAC that can facilitate better diagnosis and intervention of PDAC upon clinical translation.

A novel combination of percutaneous stenting with iodine-125 seed implantation and chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice

PURPOSE

Insertion of radioactive strips through the biliary stent has been reported to offer longer survival and patency than an uncovered conventional self-expanding metal stent in patients with unresectable malignant biliary obstruction. The aim of this study was to investigate the safety and effectiveness of intraluminal brachytherapy combined with ¹²⁵I seed implantation and transarterial infusion chemotherapy for the treatment of pancreatic head cancer with obstructive jaundice.

METHOD

From October 2012 to January 2018, 21 consecutive patients diagnosed with biliary obstruction caused by locally advanced, nonmetastatic pancreatic cancer with cytologically or histologically confirmed by biopsy were enrolled and receive treatment with intraluminal brachytherapy using ¹²⁵I seed strand and CT-guided percutaneous radioactive seed implantation therapy. The procedure-related and radiation complications were assessed. The outcomes were measured in terms of stent patency, patient survival, complications related to the procedure.

RESULT

One of the 22 patients (4.5%, 1/22) with pancreatic head cancer failed to perform the above procedure because the guidewire was unable to pass through the obstruction segment. The remaining 21 patients (95.5%, 21/22) with pancreatic head cancer with obstructive jaundice were successfully placed with biliary stents and radioactive strips through drainage tubes. The median number of ¹²⁵I seeds loaded was 15, ranging from 12 to 17. After the chemotherapy with gemcitabine and cisplatin, no adverse reaction of Grade Ⅲ ∼ Ⅳ occurred in all cases. Median stent patency was 12.50 months (95% CI: 10.26, 14.74). By May 2019, all 21 patients had died, with overall survival of 5.2-23.3 months, with a median survival of 13.20 months (95% CI: 10.96, 15.44).

CONCLUSION

Percutaneous ¹²⁵I seed implantation combined with insertion of radioactive strips through the biliary stent has the characteristics of less trauma, fewer complications, simple operation, and so on. These procedures bring remission of obstructive jaundice combined with the increased survival for the treatment of obstructive jaundice caused by unresectable pancreatic head cancer if follow-up chemotherapy is carried out. The long-term efficacy of this treatment combination needs to be confirmed by further multicenter, large sample size prospective randomized controlled studies.

Toward the Clinical Development and Validation of a Thy1-Targeted Ultrasound Contrast Agent for the Early Detection of Pancreatic Ductal Adenocarcinoma

Early detection of pancreatic ductal adenocarcinoma (PDAC) represents the most significant step toward the treatment of this aggressive lethal disease. Previously, we engineered a preclinical Thy1-targeted microbubble (MBThy1) contrast agent that specifically recognizes Thy1 antigen overexpressed in the vasculature of murine PDAC tissues by ultrasound (US) imaging. In this study, we adopted a single-chain variable fragment (scFv) site-specific bioconjugation approach to construct clinically translatable MBThy1-scFv and test for its efficacy in vivo in murine PDAC imaging, and functionally evaluated the binding specificity of scFv ligand to human Thy1 in patient PDAC tissues ex vivo.

MATERIALS AND METHODS

We recombinantly expressed the Thy1-scFv with a carboxy-terminus cysteine residue to facilitate its thioether conjugation to the PEGylated MBs presenting with maleimide functional groups. After the scFv-MB conjugations, we tested binding activity of the MBThy1-scFv to MS1 cells overexpressing human Thy1 (MS1Thy1) under liquid shear stress conditions in vitro using a flow chamber setup at 0.6 mL/min flow rate, corresponding to a wall shear stress rate of 100 seconds, similar to that in tumor capillaries. For in vivo Thy1 US molecular imaging, MBThy1-scFv was tested in the transgenic mouse model (C57BL/6J - Pdx1-Cre; KRas; Ink4a/Arf) of PDAC and in control mice (C57BL/6J) with L-arginine-induced pancreatitis or normal pancreas. To facilitate its clinical feasibility, we further produced Thy1-scFv without the bacterial fusion tags and confirmed its recognition of human Thy1 in cell lines by flow cytometry and in patient PDAC frozen tissue sections of different clinical grades by immunofluorescence staining.

RESULTS

Under shear stress flow conditions in vitro, MBThy1-scFv bound to MS1Thy1 cells at significantly higher numbers (3.0 ± 0.8 MB/cell; P < 0.01) compared with MBNontargeted (0.5 ± 0.5 MB/cell). In vivo, MBThy1-scFv (5.3 ± 1.9 arbitrary units [a.u.]) but not the MBNontargeted (1.2 ± 1.0 a.u.) produced high US molecular imaging signal (4.4-fold vs MBNontargeted; n = 8; P < 0.01) in the transgenic mice with spontaneous PDAC tumors (2-6 mm). Imaging signal from mice with L-arginine-induced pancreatitis (n = 8) or normal pancreas (n = 3) were not significantly different between the two MB constructs and were significantly lower than PDAC Thy1 molecular signal. Clinical-grade scFv conjugated to Alexa Fluor 647 dye recognized MS1Thy1 cells but not the parental wild-type cells as evaluated by flow cytometry. More importantly, scFv showed highly specific binding to VEGFR2-positive vasculature and fibroblast-like stromal components surrounding the ducts of human PDAC tissues as evaluated by confocal microscopy.

CONCLUSIONS

Our findings summarize the development and validation of a clinically relevant Thy1-targeted US contrast agent for the early detection of human PDAC by US molecular imaging.

Differences between KC and KPC pancreatic ductal adenocarcinoma mice models, in terms of their modeling biology and their clinical relevance

Pancreatic ductal adenocarcinoma (PDAC) is among the dangerous human cancers, is the 10th highly prevalent cancer, and the fourth sole cause of cancer-related mortality in the United States of America. Notwithstanding the significant commitment, the forecast for people with this burden continues to have a five-year survival rate of just 4-6%. The most critical altered genes within PDAC consist of K-ras the proto-oncogene which is usually mutationally activated above 90% cases and tumor suppressors likeTrp53 are altered at 55%. To face the burden of pancreatic ductal adenocarcinoma, a variety of genetically engineered pancreatic cancer mice models have been created over the last past years. These models have distinctive features and are not all appropriate for preclinical studies. In this review, we focus on differences between two mice models K-ras^LSL.G12D/+;Pdx-1-Cre(KC) and K-ras^LSL.G12D/+; Trp53^R172H/+; Pdx-1-Cre(KPC) in terms of their modeling biology and their clinical relevance.

A review on immunohistochemical and histopathologic validation in PET-CT findings with consideration to microRNAs

Purpose

This review provides an overview of some of the most recent clinical trials which investigated various types of cancer and other diseases, through the use of PET-CT imaging, highlighting the use of immunohistochemical stains or conventional histopathology for the validation or contradiction of their hypothesis. Furthermore, we investigate a potential new direction of research by analyzing the upcoming role of microRNAs in disease confirmation.

Methods

An extensive search of MEDLINE/PubMed and SCOPUS electronic databases was made, using the MeSH terms "positron emission tomography computed tomography" and "immunohistochemistry" as well as "SUV" and "immunohistochemistry", restricting the search by clinical trials and time period. Further searches were made for articles regarding Ki-67 and microRNAs in correlation with metabolic PET-CT uptake.

Results

Out of all 389 initial search results, 27 original articles were found relevant to the topic. Their contents were synthesized and discussed regarding the matter at hand. No relevant clinical trials involving microRNAs were found.

Conclusions

Immunohistochemical and histopathologic results remain widely used and indispensable in modern research, concerning PET-CT validation. Possible candidates for diagnosis confirmation, in future research, may reside in the further development of microRNAs.

Targeting of an antecedent proteinase by an activatable probe with deep tissue penetration facilitates early visualization and dynamic malignancy evaluation of orthotopic pancreatic ductal adenocarcinoma (PDAC)

Pancreatic ductal adenocarcinoma (PDAC) is highly lethal and most commonly diagnosed at an advanced stage; therefore, early detection with an effective approach is vital. However, due to the anatomical stealthiness and hypovascular features of PDAC, clinically available imaging techniques lack specificity and sensitivity for early detection. As important components of the tumour microenvironment, elevated matrix metalloproteinase (MMP) levels during the early stages of tumour formation lead to tumour invasion and metastases by degrading the extracellular matrix. Thus, in the current study, we hypothesized that MMPs might be promising markers for early visualization and prognosis evaluation of PDAC. An MMP activatable probe, I₇₈₀BP-PEG12, was synthesized utilizing a long wavelength near-infrared (NIR) fluorophore that could map the dynamic development of orthotopic PDAC in vivo with deep tissue penetration. Elevated MMP activity in tumours was detected as early as 4 days after tumour transplantation. At that time, the tumour diameter was approximately 3 mm, which is much smaller than the size visualized by clinical approaches. Furthermore, much higher levels of MMP activity were detected in PDAC under diabetic conditions, which promote the malignant actions of tumours. By noninvasively monitoring MMP alteration, tumour growth, and prognostic evaluation, we found that malignant actions under diabetic conditions were reversed by inhibition of MMPs. Generally, in addition to earlier visualization of PDAC, a probe targeting MMPs can facilitate dynamic monitoring of tumour progression and inhibitory treatment in vivo, which is beneficial for personal therapeutic strategy planning and optimization of PDAC management, especially for diabetic individuals.

Preoperative Imaging Evaluation after Downstaging of Pancreatic Ductal Adenocarcinoma: A Multi-Center Study

Introduction: Evaluation of pancreatic ductal adenocarcinoma (PDAC) after chemoradiotherapy downstaging is challenging due to computed tomography (CT) overestimation of tumor extension and residual vascular involvement, limiting access to surgery to some patients with potentially resectable tumors. With this study, we wanted to assess which radiological findings are most reliable at pre-operative imaging in the evaluation of PDAC after chemoradiotherapy in order to achieve complete resection. Methods: We retrospectively enrolled 71 patients with locally advanced and borderline resectable PDAC who underwent neoadjuvant chemoradiotherapy. Pre-operative CT or magnetic resonance (MR) have been evaluated by three radiologists to assess major qualitative and quantitative parameters of lesions. Accuracy, sensitivity, and specificity compared to anatomopathological results were evaluated for each parameter. Cohen’s K-coefficient has been calculated to evaluate the inter-observer agreement (IOA). Both single and consensus lecture have been tested. Different dimensional cut-offs were tested to categorize tumors according to their major axis and to compare with anatomopathological diameter, tumor persistence, and margin infiltration. Results: A 25 mm cut-off was 67% sensitive, 90% specific, and 77% accurate in assessing real tumor dimension. 25 mm cut-off reported a 64% sensitivity, 78% specificity, and 69% accuracy in assessing R0 resection. Each 5 mm increment of major axis dimension there is an odds ratio (OR) 1.79 (95% CI 1.13–2.80, p = 0.012) for R+ resection. Imaging presence of the perivascular cuff is not associated with tumor persistence and resection margin infiltration (p = 0.362). Lesion enhancement and pattern homogeneity were not accurate in determining tumor persistence. IOA was generally poor to fair, except for >25 mm cut-off classification where IOA was moderate. Diagnostic accuracy is superior in consensus lecture rather than single lecture. Conclusion: Imaging methods tend to underestimate PDAC resectability after neoadjuvant-CRT. IOA is poor to fair in evaluating most of the qualitative parameters of downstaged pancreatic adenocarcinoma. Surgery should be considered for downstaged borderline resectable PDACs, independently from perivascular cuff presence, especially for tumors smaller than 25 mm.

Advances in Diagnostic and Intraoperative Molecular Imaging of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. To improve outcomes, there is a critical need for improved tools for detection, accurate staging, and resectability assessment. This could improve patient stratification for the most optimal primary treatment modality. Molecular imaging, used in combination with tumor-specific imaging agents, can improve established imaging methods for PDAC. These novel, tumor-specific imaging agents developed to target specific biomarkers have the potential to specifically differentiate between malignant and benign diseases, such as pancreatitis. When these agents are coupled to various types of labels, this type of molecular imaging can provide integrated diagnostic, noninvasive imaging of PDAC as well as image-guided pancreatic surgery. This review provides a detailed overview of the current clinical imaging applications, upcoming molecular imaging strategies for PDAC, and potential targets for imaging, with an emphasis on intraoperative imaging applications.

Pancreatic Adenocarcinoma Staging in the Era of Preoperative Chemotherapy and Radiation Therapy

Pancreatic ductal adenocarcinoma (PDA) remains among the most challenging malignancies to treat. At diagnosis, the tumor often already extends beyond the confines of the pancreas, spreading to an extent such that primary surgery with curative intent is very rarely feasible. Considerable momentum is now being given to a treatment strategy involving neoadjuvant chemotherapy or chemotherapy and radiation therapy in patients with nonmetastatic PDA. The main advantage of this strategy is better selection of patients likely to benefit from curative-intent surgery through the achievement of negative resection margins. Patients with rapidly progressive disease are identified and are spared ineffective surgery with its attendant morbidity. Neoadjuvant therapy can downstage tumors classified as locally advanced at initial imaging studies to resectable tumors. However, the imaging study evaluation of the response to neoadjuvant therapy is extremely complex. Thus, the diagnostic performance of imaging studies is not sufficient to ensure the accurate selection of patients in whom negative-margin resection is likely to be achieved. More specifically, standard criteria for predicting vascular invasion, based on the amount of tumor-vessel contact, are not valid after neoadjuvant therapy. ^©RSNA, 2018.

Thy1-Targeted Microbubbles for Ultrasound Molecular Imaging of Pancreatic Ductal Adenocarcinoma

Purpose: To engineer a dual human and murine Thy1-binding single-chain-antibody ligand (Thy1-scFv) for contrast microbubble-enhanced ultrasound molecular imaging of pancreatic ductal adenocarcinoma (PDAC).Experimental Design: Thy1-scFv were engineered using yeast-surface-display techniques. Binding to soluble human and murine Thy1 and to Thy1-expressing cells was assessed by flow cytometry. Thy1-scFv was then attached to gas-filled microbubbles to create MBThy1-scFv Thy1 binding of MBThy1-scFv to Thy1-expressing cells was evaluated under flow shear stress conditions in flow-chamber experiments. MBscFv-scrambled and MBNon-targeted were used as negative controls. All microbubble types were tested in both orthotopic human PDAC xenografts and transgenic PDAC mice in vivoResults: Thy1-scFv had a KD of 3.4 ± 0.36 nmol/L for human and 9.2 ± 1.7 nmol/L for murine Thy1 and showed binding to both soluble and cellularly expressed Thy1. MBThy1-scFv was attached to Thy1 with high affinity compared with negative control microbubbles (P < 0.01) as assessed by flow cytometry. Similarly, flow-chamber studies showed significantly (P < 0.01) higher binding of MBThy1-scFv (3.0 ± 0.81 MB/cell) to Thy1-expressing cells than MBscFv-scrambled (0.57 ± 0.53) and MBNon-targeted (0.43 ± 0.53). In vivo ultrasound molecular imaging using MBThy1-scFv demonstrated significantly higher signal (P < 0.01) in both orthotopic (5.32 ± 1.59 a.u.) and transgenic PDAC (5.68 ± 2.5 a.u.) mice compared with chronic pancreatitis (0.84 ± 0.6 a.u.) and normal pancreas (0.67 ± 0.71 a.u.). Ex vivo immunofluorescence confirmed significantly (P < 0.01) increased Thy1 expression in PDAC compared with chronic pancreatitis and normal pancreas tissue.Conclusions: A dual human and murine Thy1-binding scFv was designed to generate contrast microbubbles to allow PDAC detection with ultrasound. Clin Cancer Res; 24(7); 1574-85. ©2018 AACR.

Detecting circulating tumor material and digital pathology imaging during pancreatic cancer progression

Pancreatic cancer (PC) is a leading cause of cancer-related death worldwide. Clinical symptoms typically present late when treatment options are limited and survival expectancy is very short. Metastatic mutations are heterogeneous and can accumulate up to twenty years before PC diagnosis. Given such genetic diversity, detecting and managing the complex states of disease progression may be limited to imaging modalities and markers present in circulation. Recent developments in digital pathology imaging show potential for early PC detection, making a differential diagnosis, and predicting treatment sensitivity leading to long-term survival in advanced stage patients. Despite large research efforts, the only serum marker currently approved for clinical use is CA 19-9. Utility of CA 19-9 has been shown to improve when it is used in combination with PC-specific markers. Efforts are being made to develop early-screening assays that can detect tumor-derived material, present in circulation, before metastasis takes a significant course. Detection of markers that identify circulating tumor cells and tumor-derived extracellular vesicles (EVs) in biofluid samples offers a promising non-invasive method for this purpose. Circulating tumor cells exhibit varying expression of epithelial and mesenchymal markers depending on the state of tumor differentiation. This offers a possibility for monitoring disease progression using minimally invasive procedures. EVs also offer the benefit of detecting molecular cargo of tumor origin and add the potential to detect circulating vesicle markers from tumors that lack invasive properties. This review integrates recent genetic insights of PC progression with developments in digital pathology and early detection of tumor-derived circulating material.

Novel Diagnostic and Predictive Biomarkers in Pancreatic Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease for a multitude of reasons including very late diagnosis. This in part is due to the lack of understanding of the biological behavior of PDAC and the ineffective screening for this disease. Significant efforts have been dedicated to finding the appropriate serum and imaging biomarkers to help early detection and predict response to treatment of PDAC. Carbohydrate antigen 19-9 (CA 19-9) has been the most validated serum marker and has the highest positive predictive value as a stand-alone marker. When combined with carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA 125), CA 19-9 can help predict the outcome of patients to surgery and chemotherapy. A slew of novel serum markers including multimarker panels as well as genetic and epigenetic materials have potential for early detection of pancreatic cancer, although these remain to be validated in larger trials. Imaging studies may not correlate with elevated serum markers. Critical features for determining PDAC include the presence of a mass, dilated pancreatic duct, and a duct cut-off sign. Features that are indicative of early metastasis includes neurovascular bundle involvement, duodenal invasion, and greater post contrast enhancement. 18-F-fluorodeoxyglucose (18-FDG) radiotracer uptake and changes following treatment may predict patient overall survival following treatment. Similarly, pretreatment apparent diffusion coefficient (ADC) values may predict prognosis with lower ADC lesions having worse outcome. Although these markers have provided significant improvement in the care of pancreatic cancer patients, further advancements can be made with perhaps better combination of markers or discovery of unique marker(s) to pancreatic cancer.

Ultrasound Molecular Imaging With BR55 in Patients With Breast and Ovarian Lesions: First-in-Human Results

Purpose We performed a first-in-human clinical trial on ultrasound molecular imaging (USMI) in patients with breast and ovarian lesions using a clinical-grade contrast agent (kinase insert domain receptor [KDR] -targeted contrast microbubble [MB_KDR]) that is targeted at the KDR, one of the key regulators of neoangiogenesis in cancer. The aim of this study was to assess whether USMI using MB_KDR is safe and allows assessment of KDR expression using immunohistochemistry (IHC) as the gold standard. Methods Twenty-four women (age 48 to 79 years) with focal ovarian lesions and 21 women (age 34 to 66 years) with focal breast lesions were injected intravenously with MB_KDR (0.03 to 0.08 mL/kg of body weight), and USMI of the lesions was performed starting 5 minutes after injection up to 29 minutes. Blood pressure, ECG, oxygen levels, heart rate, CBC, and metabolic panel were obtained before and after MB_KDR administration. Persistent focal MB_KDR binding on USMI was assessed. Patients underwent surgical resection of the target lesions, and tissues were stained for CD31 and KDR by IHC. Results USMI with MB_KDR was well tolerated by all patients without safety concerns. Among the 40 patients included in the analysis, KDR expression on IHC matched well with imaging signal on USMI in 93% of breast and 85% of ovarian malignant lesions. Strong KDR-targeted USMI signal was present in 77% of malignant ovarian lesions, with no targeted signal seen in 78% of benign ovarian lesions. Similarly, strong targeted signal was seen in 93% of malignant breast lesions with no targeted signal present in 67% of benign breast lesions. Conclusion USMI with MB_KDR is clinically feasible and safe, and KDR-targeted USMI signal matches well with KDR expression on IHC. This study lays the foundation for a new field of clinical USMI in cancer.

Matrix-regulated integrin αvβ5 maintains α5β1-dependent desmoplastic traits prognostic of neoplastic recurrence

Desmoplasia, a fibrotic mass including cancer-associated fibroblasts (CAFs) and self-sustaining extracellular matrix (D-ECM), is a puzzling feature of pancreatic ductal adenocarcinoma (PDACs). Conflicting studies have identified tumor-restricting and tumor-promoting roles of PDAC-associated desmoplasia, suggesting that individual CAF/D-ECM protein constituents have distinguishable tumorigenic and tumor-repressive functions. Using 3D culture of normal pancreatic versus PDAC-associated human fibroblasts, we identified a CAF/D-ECM phenotype that correlates with improved patient outcomes, and that includes CAFs enriched in plasma membrane-localized, active α₅β₁-integrin. Mechanistically, we established that TGFβ is required for D-ECM production but dispensable for D-ECM-induced naïve fibroblast-to-CAF activation, which depends on α_vβ₅-integrin redistribution of pFAK-independent active α₅β₁-integrin to assorted endosomes. Importantly, the development of a simultaneous multi-channel immunofluorescence approach and new algorithms for computational batch-analysis and their application to a human PDAC panel, indicated that stromal localization and levels of active SMAD2/3 and α₅β₁-integrin distinguish patient-protective from patient-detrimental desmoplasia and foretell tumor recurrences, suggesting a useful new prognostic tool.

DOI:http://dx.doi.org/10.7554/eLife.20600.001

Tumors are not entirely made out of cancerous cells. They contain many other components – referred to as tumor stroma – that may either encourage or hinder the tumor’s growth. Tumor stroma includes non-cancerous cells and a framework of fibrous sugary proteins, called the extracellular matrix, which surround and signal to cells while providing physical support.

In the most common and aggressive form of pancreatic cancer, the stroma often makes up the majority of the tumor’s mass. Sometimes the stroma of these pancreatic tumors can protect the cancer cells from anti-cancer drugs. Researchers have therefore been interested in finding out exactly which aspects of the tumor stroma shield and support cancer cells, and which impede their growth and progression. Answering these questions could make it possible to develop new drugs that will change a tumor-supporting stroma into one that hinders the tumor’s growth and spread.

The most abundant cells in the stroma of pancreatic tumors are called cancer-associated fibroblasts. Healthy specialized fibroblasts – known as pancreatic stellate cells – help to build and maintain the ‘normal’ extracellular matrix and so these cells normally restrict a tumor’s development. However, cancer cells can adapt healthy fibroblasts into cancer-associated fibroblasts, which produce an altered extracellular matrix that could allow the tumor to grow.

Franco-Barraza et al. have now compared healthy and cancer-associated fibroblasts from patients’ pancreatic tumors. One of the main differences between these two cell types was the location of the activated form of a molecule called α₅β₁-integrin. Healthy fibroblasts, in a normal extracellular matrix, have active α₅β₁-integrin on the surface of the cell. However, a number of tumor-promoting signals, including some from the altered extracellular matrix, could force the active α₅β₁-integrins to relocate inside the fibroblasts instead. In further experiments, where the activated integrin was retained at the cell surface, the fibroblasts were able to resist the influence of the cancer-associated extracellular matrix. Then again, if the active α₅β₁-integrins were directed inside the cells, healthy cells turned into cancer-associated fibroblasts.

With this information in hand, Franco-Barraza et al. examined tumor samples from over a hundred pancreatic cancer patients using a new microscopy-based technique that distinguishes cancer cells from stroma cells. The analysis confirmed the pattern observed in the laboratory: those patients who appeared to produce more normal extracellular matrix and have active α₅β₁-integrin localized mostly to the surface of the cells survived longer without the cancer returning than those patients who lacked these stroma traits. Samples from patients with kidney cancer also showed similar results and, as before, an altered extracellular matrix was linked to a worse outcome of the disease.

Together these findings suggest that if future studies uncover ways to relocate or maintain active α₅β₁-integrin to the cell surface of fibroblasts they could lead to new treatments to restrict the growth of tumors in cancer patients.

DOI:http://dx.doi.org/10.7554/eLife.20600.002