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Well-preserved molecular cargo in circulating extracellular vesicles (EVs) offers an ideal material for detecting oncogenic gene alterations in cancer patients, providing a noninvasive diagnostic solution for detection of disease status and monitoring treatment response. Therefore, technologies that conveniently isolate EVs with sufficient efficiency are desperately needed. Here, a lipid labeling and click chemistry-based EV capture platform ("Click Beads"), which is ideal for EV message ribonucleic acid (mRNA) assays due to its efficient, convenient, and rapid purification of EVs, enabling downstream molecular quantification using reverse transcription digital polymerase chain reaction (RT-dPCR) is described and demonstrated. Ewing sarcoma protein (EWS) gene rearrangements and kirsten rat sarcoma viral oncogene homolog (KRAS) gene mutation status are detected and quantified using EVs isolated by Click Beads and matched with those identified in biopsy specimens from Ewing sarcoma or pancreatic cancer patients. Moreover, the quantification of gene alterations can be used for monitoring treatment responses and disease progression.

Early cancer detection by cell-free DNA faces multiple challenges: low fraction of tumor cell-free DNA, molecular heterogeneity of cancer, and sample sizes that are not sufficient to reflect diverse patient populations. Here, we develop a cancer detection approach to address these challenges. It consists of an assay, cfMethyl-Seq, for cost-effective sequencing of the cell-free DNA methylome (with > 12-fold enrichment over whole genome bisulfite sequencing in CpG islands), and a computational method to extract methylation information and diagnose patients. Applying our approach to 408 colon, liver, lung, and stomach cancer patients and controls, at 97.9% specificity we achieve 80.7% and 74.5% sensitivity in detecting all-stage and early-stage cancer, and 89.1% and 85.0% accuracy for locating tissue-of-origin of all-stage and early-stage cancer, respectively. Our approach cost-effectively retains methylome profiles of cancer abnormalities, allowing us to learn new features and expand to other cancer types as training cohorts grow.

Tumor-derived extracellular vesicles (EVs) play essential roles in intercellular communication during tumor growth and metastatic evolution. Currently, little is known about the possible roles of tumor-derived EVs in sarcoma because the lack of specific surface markers makes it technically challenging to purify sarcoma-derived EVs. In this study, a specific purification system is developed for Ewing sarcoma (ES)-derived EVs by coupling covalent chemistry-mediated EV capture/ release within a nanostructure-embedded microchip. The purification platform-ES-EV Click Chip-takes advantage of specific anti-LINGO-1 recognition and sensitive click chemistry-mediated EV capture, followed by disulfide cleavage-driven EV release. Since the device is capable of specific and efficient purification of intact ES EVs with high purity, ES-EV Click Chip is ideal for conducting downstream functional studies of ES EVs. Absolute quantification of the molecular hallmark of ES (i.e., EWS rearrangements) using reverse transcription Droplet Digital PCR enables specific quantification of ES EVs. The purified ES EVs can be internalized by recipient cells and transfer their mRNA cargoes, exhibiting their biological intactness and potential role as biological shuttles in intercellular communication.

Hepatocellular carcinoma (HCC) is a leading cause of mortality. Checkpoint inhibitors of programmed cell death protein-1 (PD-1) and programmed death-ligand 1 (PD-L1) have shown great efficacy, but lack biomarkers that predict response. Circulating tumor cells (CTCs) have promise as a liquid-biopsy biomarker; however, data on HCC CTCs expressing PD-L1 have not been reported. We sought to detect PD-L1-expressing HCC-CTCs and investigated their role as a prognostic and predictive biomarker. Using an antibody-based platform, CTCs were enumerated/phenotyped from a prospective cohort of 87 patients with HCC (49 early-stage, 22 locally advanced, and 16 metastatic), 7 patients with cirrhosis, and 8 healthy controls. Immunocytochemistry identified total HCC CTCs (4',6-diamidino-2-phenylindole-positive [DAPI+]/cytokeratin-positive [CK+]/clusters of differentiation 45-negative [CD45-]) and a subpopulation expressing PD-L1 (DAPI+/CK+/PD-L1+/CD45-). PD-L1+ CTCs were identified in 4 of 49 (8.2%) early-stage patients, but 12 of 22 (54.5%) locally advanced and 15 of 16 (93.8%) metastatic patients, accurately discriminating early from locally advanced/metastatic HCC (sensitivity = 71.1%, specificity = 91.8%, area under the receiver operating characteristic curve = 0.807; P

Somatic copy number alterations (SCNAs) are important genetic drivers of many cancers. We investigated the feasibility of obtaining SCNA profiles from circulating tumor cells (CTCs) as a molecular liquid biopsy for hepatocellular carcinoma (HCC). CTCs from ten HCC patients underwent SCNA profiling. The Cancer Genome Atlas (TCGA) SCNA data were used to develop a cancer origin classification model, which was then evaluated for classifying 44 CTCs from multiple cancer types. Sequencing of 18 CTC samples (median: 4 CTCs/sample) from 10 HCC patients using a low-resolution whole-genome sequencing strategy (median: 0.88 million reads/sample) revealed frequent SCNAs in previously reported HCC regions such as 8q amplifications and 17p deletions. SCNA profiling revealed that CTCs share a median of 80% concordance with the primary tumor. CTCs had SCNAs not seen in the primary tumor, some with prognostic implications. Using a SCNA profiling model, the tissue of origin was correctly identified for 32/44 (73%) CTCs from 12/16 (75%) patients with different cancer types.

BackgroundPatients with early-stage pancreatic neuroendocrine tumors (PNETs) may develop metastatic recurrences despite undergoing potentially curative pancreas resections. We sought to identify factors predictive of metastatic recurrences and develop a prognostication strategy to predict recurrence-free survival (RFS) in resected PNETs.MethodsPatients with localized PNETs undergoing surgical resection between 1989 and 2015 were identified. Univariate and multivariate analysis were used to identify potential predictors of post-resection metastasis. A score-based prognostication system was devised using the identified factors. The bootstrap model validation methodology was utilized to estimate the external validity of the proposed prognostication strategy.ResultsOf the 140 patients with completely resected early-stage PNETs, overall 5- and 10-year RFS were 84.6% and 67.1%, respectively. The median follow-up was 56 months. Multivariate analysis identified tumor size > 5 cm, Ki-67 index 8-20%, lymph node involvement, and high histologic grade (G3, or Ki-67 > 20%) as independent predictors of post-resection metastatic recurrence. A scoring system based on these factors stratified patients into three prognostic categories with distinct 5-year RFS: 96.9%, 54.8%, and 33.3% (P

Current clinicopathologic staging systems and serum biomarkers poorly discriminate tumor biology in hepatocellular carcinoma (HCC), with high recurrence rates following curative-intent surgical resection and liver transplantation (LT). Identification of accurate biomarkers for improved prognostication and treatment selection is a critical unmet need. We sought to develop a novel "liquid-biopsy" assay capable of detecting HCC circulating tumor cells (CTCs) and characterizing phenotypic subpopulations with prognostic significance. Using HCC cell lines, a tissue microarray, and human blood samples, an antibody cocktail targeting the cell-surface markers asialoglycoprotein receptor (ASGPR), glypican-3, and epithelial cell adhesion molecule was optimized for HCC CTC capture using the NanoVelcro CTC Assay. The ability of HCC CTCs and vimentin (VIM)-positive CTCs (a subpopulation expressing an epithelial-to-mesenchymal phenotype) to accurately discriminate tumor stage, recurrence, progression, and overall survival (OS) was evaluated in a prospective study of 80 patients. Multimarker capture detected greater numbers of CTCs than any individual antibody alone for both cell line and patient samples (P < 0.001). HCC CTCs were identified in 59/61 (97%) patients, and HCC (median, 6 CTCs) and non-HCC patients (median, 1 CTC; area under the receiver operating characteristic curve [AUROC] = 0.92; P < 0.001; sensitivity = 84.2%; specificity = 88.5%) were accurately discriminated. VIM-positive CTCs accurately discriminated early-stage, LT eligible patients (median, 0 CTCs) from locally advanced/metastatic, LT ineligible patients (median, 6 CTCs; AUROC = 0.89; P = 0.001; sensitivity = 87.1%; specificity = 90.0%), and predicted OS for all patients (hazard ratio [HR], 2.21; P = 0.001), and faster recurrence after curative-intent surgical or locoregional therapy in potentially curable early-stage HCC (HR, 3.14; P = 0.002). In conclusion, we developed a novel multimarker CTC enrichment assay that detects HCC CTCs with high efficiency and accuracy. A phenotypic subpopulation of VIM-positive CTCs appears to signify the presence of aggressive underlying disease and occult metastases and may have important implications for treatment selection. Liver Transplantation 24 946-960 2018 AASLD.

BACKGROUND:Occult metastatic tumors, below imaging thresholds, are a limitation of staging systems that rely on cross-sectional imaging alone and are a cause of the routine understaging of pancreatic ductal adenocarcinomas (PDACs). We investigated circulating tumor cells (CTCs) as a preoperative predictor of occult metastatic disease and as a prognostic biomarker for PDAC patients. EXPERIMENTAL DESIGN:A total of 126 patients (100 with cancer, 26 with benign disease) were enrolled in our study and CTCs were identified and enumerated from 4 mL of venous blood using the microfluidic NanoVelcro assay. CTC enumeration was correlated with clinicopathologic variables and outcomes following both surgical and systemic therapies. RESULTS:CTCs were identified in 78% of PDAC patients and CTC counts correlated with increasing stage (ρ = 0.42, p

Circulating tumor cells (CTCs) are cancer cells shredded from either a primary tumor or a metastatic site and circulate in the blood as the potential cellular origin of metastasis. By detecting and analyzing CTCs, we will be able to noninvasively monitor disease progression in individual cancer patients and obtain insightful information for assessing disease status, thus realizing the concept of "tumor liquid biopsy". However, it is technically challenging to identify CTCs in patient blood samples because of the extremely low abundance of CTCs among a large number of hematologic cells. In order to address this challenge, our research team at UCLA pioneered a unique concept of "NanoVelcro" cell-affinity substrates, in which CTC capture agent-coated nanostructured substrates were utilized to immobilize CTCs with remarkable efficiency. Four generations of NanoVelcro CTC assays have been developed over the past decade for a variety of clinical utilities. The 1st-gen NanoVelcro Chips, composed of a silicon nanowire substrate (SiNS) and an overlaid microfluidic chaotic mixer, were created for CTC enumeration. The 2nd-gen NanoVelcro Chips (i.e., NanoVelcro-LMD), based on polymer nanosubstrates, were developed for single-CTC isolation in conjunction with the use of the laser microdissection (LMD) technique. By grafting thermoresponsive polymer brushes onto SiNS, the 3rd-gen Thermoresponsive NanoVelcro Chips have demonstrated the capture and release of CTCs at 37 and 4 °C respectively, thereby allowing for rapid CTC purification while maintaining cell viability and molecular integrity. Fabricated with boronic acid-grafted conducting polymer-based nanomaterial on chip surface, the 4th-gen NanoVelcro Chips (Sweet chip) were able to purify CTCs with well-preserved RNA transcripts, which could be used for downstream analysis of several cancer specific RNA biomarkers. In this review article, we will summarize the development of the four generations of NanoVelcro CTC assays, and the clinical applications of each generation of devices.

Recent cancer research has demonstrated the existence of circulating tumor cells (CTCs) in cancer patient's blood. Once identified, CTC biomarkers will be invaluable tools for clinical diagnosis, prognosis and treatment. In this review, we propose ex vivo culture as a rational strategy for large scale amplification of the limited numbers of CTCs from a patient sample, to derive enough CTCs for accurate and reproducible characterization of the biophysical, biochemical, gene expressional and behavioral properties of the harvested cells. Because of tumor cell heterogeneity, it is important to amplify all the CTCs in a blood sample for a comprehensive understanding of their role in cancer metastasis. By analyzing critical steps and technical issues in ex vivo CTC culture, we developed a cost-effective and reproducible protocol directly culturing whole peripheral blood mononuclear cells, relying on an assumed survival advantage in CTCs and CTC-like cells over the normal cells to amplify this specified cluster of cancer cells.

To understand the potential and limitations of circulating tumor cell (CTC) sequencing for molecular diagnostics, we investigated the feasibility of identifying the ubiquitous KRAS mutation in single CTCs from pancreatic cancer (PC) patients. We used the NanoVelcro/laser capture microdissection CTC platform, combined with whole genome amplification and KRAS Sanger sequencing. We assessed both KRAS codon-12 coverage and the degree that allele dropout during whole genome amplification affected the detection of KRAS mutations from single CTCs. We isolated 385 single cells, 163 from PC cell lines and 222 from the blood of 12 PC patients, and obtained KRAS sequence coverage in 218 of 385 single cells (56.6%). For PC cell lines with known KRAS mutations, single mutations were detected in 67% of homozygous cells but only 37.4% of heterozygous single cells, demonstrating that both coverage and allele dropout are important causes of mutation detection failure from single cells. We could detect KRAS mutations in CTCs from 11 of 12 patients (92%) and 33 of 119 single CTCs sequenced, resulting in a KRAS mutation detection rate of 27.7%. Importantly, KRAS mutations were never found in the 103 white blood cells sequenced. Sequencing of groups of cells containing between 1 and 100 cells determined that at least 10 CTCs are likely required to reliably assess KRAS mutation status from CTCs.

BackgroundLong-term survival (LTS) is uncommon for patients with pancreatic ductal adenocarcinoma (PDAC). We sought to identify factors that predict 10-year, LTS after resection of PDAC.MethodsWe identified all patients with PDAC who underwent resection at UCLA after 1990 and included all patients eligible for observed LTS (1/1/1990-12/31/2004). An independent pathologist reconfirmed the diagnosis of PDAC in patients with LTS. Logistic regression was used to predict LTS on the basis of patient and tumor characteristics.ResultsOf 173 included patients, 53% were male, median age at diagnosis was 66 years, and median survival was 23 months. The rate of observed LTS was 12.1% (n = 21). Age, sex, number of lymph nodes evaluated, margin status, lymphovascular invasion, and adjuvant chemotherapy and radiation were not associated with LTS. The following were associated with LTS on bivariate analysis: low AJCC stage (Ia, Ib, IIa) (P = .034), negative lymph node status (P = .034), low grade (well-, moderately-differentiated) (P = .001), and absence of perineural invasion (P = .019). Only low grade (odds ratio 7.17, P = .012) and absent perineural invasion (odds ratio 3.28, P = .036) were independently associated with increased odds of LTS. Our multivariate model demonstrated good discriminatory power for LTS, as indicated by a c-statistic of 0.7856.ConclusionAbsence of perineural invasion and low tumor grade were associated with greater likelihood of LTS. Understanding the tumor biology of LTS may provide critical insight into a disease that is typically marked by aggressive behavior and limited survival.

A pretargeted oncologic positron emission tomography (PET) imaging that leverages the power of supramolecular nanoparticles with in vivo bioorthogonal chemistry was demonstrated for the clinically relevant problem of tumor imaging. The advantages of this approach are that (i) the pharmacokinetics (PKs) of tumor-targeting and imaging agents can be independently altered via chemical alteration to achieve the desired in vivo performance and (ii) the interplay between the two PKs and other controllable variables confers a second layer of control toward improved PET imaging. In brief, we utilized supramolecular chemistry to synthesize tumor-targeting nanoparticles containing transcyclooctene (TCO, a bioorthogonal reactive motif), called TCO⊂SNPs. After the intravenous injection and subsequent concentration of the TCO⊂SNPs in the tumors of living mice, a small molecule containing both the complementary bioorthogonal motif (tetrazine, Tz) and a positron-emitting radioisotope ((64)Cu) was injected to react selectively and irreversibly to TCO. High-contrast PET imaging of the tumor mass was accomplished after the rapid clearance of the unreacted (64)Cu-Tz probe. Our nanoparticle approach encompasses a wider gamut of tumor types due to the use of EPR effects, which is a universal phenomenon for most solid tumors.

Liquid biopsy of tumor through isolation of circulating tumor cells (CTCs) allows non-invasive, repetitive, and systemic sampling of disease. Although detecting and enumerating CTCs is of prognostic significance in metastatic cancer, it is conceivable that performing molecular and functional characterization on CTCs will reveal unprecedented insight into the pathogenic mechanisms driving lethal disease. Nanomaterial-embedded cancer diagnostic platforms, i.e., NanoVelcro CTC Assays represent a unique rare-cell sorting method that enables detection isolation, and characterization of CTCs in peripheral blood, providing an opportunity to noninvasively monitor disease progression in individual cancer patients. Over the past decade, a series of NanoVelcro CTC Assays has been demonstrated for exploring the full potential of CTCs as a clinical biomarker, including CTC enumeration, phenotyping, genotyping and expression profiling. In this review article, the authors will briefly introduce the development of three generations of NanoVelcro CTC Assays, and highlight the clinical applications of each generation for various types of solid cancers, including prostate cancer, pancreatic cancer, lung cancer, and melanoma.

BackgroundThe 2012 Sendai Criteria recommend that patients with 3 cm or larger branch duct intraductal papillary mucinous neoplasms (BD-IPMN) without any additional "worrisome features" or "high-risk stigmata" may undergo close observation. Furthermore, endoscopic ultrasound (EUS) is not recommended for BD-IPMN 3 cm were removed based on size alone.Discussion/conclusionsOur results suggest that "larger" size on noninvasive imaging can indicate high-grade/invasive cysts, and EUS-FNA may help identify "smaller" cysts with high-grade/invasive pathology.

PurposeIntact antibodies have a long serum persistence resulting in high background signal that inhibits their direct translation as imaging agents. Engineering of antibody fragments through the introduction of mutations in the fragment crystallizable (Fc) region can dramatically reduce serum persistence. We sought to develop a Fc-mutated, anti-CA19-9 antibody fragment (anti-CA 19-9 scFv-Fc H310A) to provide micro-positron emission tomography (microPET) imaging of pancreatic cancer xenografts.ProceduresThe anti-CA19-9 scFv-Fc H310A was successfully expressed and purified. Biochemical characterization included size exclusion chromatography, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), Western blot, and flow cytometry. The antibody fragment was labeled with iodine-124 ((124)I) and injected into mice containing human pancreatic cancer xenografts. MicroPET/CT images were then obtained. Blood, organ, and tumor radioactivity was measured and expressed as the percent of injected dose per gram of tissue (%ID/g).ResultsBiochemical characterization was consistent with the creation of a 105 kD dimer containing a human Fc region. Flow cytometry demonstrated antigen-specific binding, and cell-based ELISA further established a dissociation constant (K D) of 10.7 nM. (124)I-labeled scFv-Fc H310A localized to the antigen-positive tumor xenografts as detected by microPET. Objective confirmation of targeting was demonstrated by higher %ID/g in the antigen-positive tumor compared to the blood, antigen-negative tumor, and liver.ConclusionsWe successfully engineered and produced an anti-CA19-9 scFv-Fc H310A antibody fragment that retains similar affinity when compared to the parental intact murine antibody. Additionally, our engineered and mutated fragment exhibited antigen-specific microPET imaging of both subcutaneous and orthotopic pancreatic cancer xenografts at early time points secondary to decreased serum half-life.

Lack of a universal site-specific conjugation methodology for antibodies limits their potential to be developed as tumor-specific imaging agents or targeted therapeutics. A potential mechanism for site-specific conjugation involves utilization of the conserved N-glycosylation site in the CH2 domain. We sought to develop an antibody with an altered azido-sugar at this site whereby site-specific label could be added. The HB8059 hybridoma was cultured with peracetylated N-azidoacetlymannosamine (Ac4ManNAz). The resulting azido-sugar antibody was conjugated to phosphine-polyethylene glycol (PEG3)-biotin via a modified Staudinger reaction. Biochemical and functional characterization of the biotinylated antibody was performed. The azido-sugar antibody was also labeled with DyLight-650-Phosphine and injected into mice harboring pancreatic cancer xenografts. The tumors were dissected and imaged utilizing an IVIS fluorescent camera. The antibody was successfully produced in 100 μM Ac4ManNAz. The biotinylated antibody demonstrated a 50 kDa heavy and 25 kDa light chain on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, but demonstrated a single band at 50 kDa on western blot. Treatment with a N-linked glycosidase extinguished the band. Flow cytometry demonstrated antigen-specific binding of CA19-9-positive cells and the antibody localized to the antigen-positive tumor in vivo. We successfully produced an antibody with an azido-sugar at the conserved CH2 glycosylation site. We were able to utilize this azide to label the antibody with biotin or fluorescent label and demonstrate that the label is added in a site-specific manner to the heavy chain, N-linked glycosylation site. Finally, we demonstrated functionality of our antibody for in vitro and in vivo targeting of pancreatic cancer cells.

BackgroundPancreatic ductal adenocarcinoma (PDAC) patients demonstrate highly variable survival within each stage of the American Joint Committee on Cancer (AJCC) staging system. We hypothesize that tumor grade is partly responsible for this variation. Recently our group developed a novel tumor, node, metastasis, grade (TNMG) classification system utilizing Surveillance Epidemiology and End Results (SEER) data in which the presence of high tumor grade results in advancement to the next higher AJCC stage. This study's objective was to validate this TNMG staging system utilizing single-institution data.MethodsAll patients with PDAC who underwent resection at UCLA between 1990 and 2009 were identified. Clinicopathologic data reviewed included age, sex, node status, tumor size, grade, and stage. Grade was redefined as a dichotomous variable. The impact of grade on survival was assessed by Cox regression analysis. Disease was restaged into the TNMG system and compared to the AJCC staging system.ResultsWe identified 256 patients who underwent resection for PDAC. Patients with low-grade tumors experienced a 13-month improvement in median survival compared to those with high-grade tumors. On multivariate analysis, tumor grade was the strongest predictor of survival with a hazard ratio of 2.02 (p = 0.0005). Restaging disease according to the novel TNMG staging system resulted in improved survival discrimination between stages compared to the current AJCC system.ConclusionsWe were able to demonstrate that grade is one of the strongest independent prognostic factors in PDAC. Restaging with our novel TNMG system demonstrated improved prognostication. This system offers an effective and convenient way of adding grade to the current AJCC staging system.

BackgroundAntibody-based therapeutics is a rapidly growing field. Small engineered antibody fragments demonstrate similar antigen affinity compared with the parental antibody but have a shorter serum half-life and possess the ability to be conjugated to nanoparticles. The goal of this study was to engineer an anti-carbohydrate antigen 19-9 (CA19-9) cys-diabody fragment in hopes of targeting nanoparticles to pancreatic cancer.MethodsThe anti-CA19-9 cys-diabody was created by engineering a C-terminal cysteine residue into the DNA single-chain Fv construct of the anti-CA19-9 diabody and expressed in NS0 cells. Maleimide chemistry was used to conjugate the cys-diabody to polymerized liposomal nanoparticles (PLNs) through the cysteine residues. Flow cytometry was used to evaluate targeting of cys-diabody and cys-diabody-PLN conjugate to human pancreatic cancer cell lines. The cys-diabody was radiolabeled with a positron emitter ((124)I) and evaluated in a mouse model of CA19-9-positive and CA19-9-negative xenografts with micro-positron emission tomography/micro-computed tomography at successive time intervals after injection. Percentage of injected dose per gram of radioactivity was measured in blood and tumor to provide objective confirmation of the micro-positron emission tomographic images.ResultsTumor xenograft imaging of the anti-CA19-9 cys-diabody demonstrated an average tumor-to-blood ratio of 3.0 and positive-to-negative tumor ratio of 7.4. Successful conjugation of the cys-diabody to PLNs was indicated by flow cytometry showing specific binding of cys-diabody-PLN conjugate to human pancreatic cancer cells in vitro.ConclusionsOur results show that the anti-CA19-9 cys-diabody targets pancreatic cancer providing specific molecular imaging in tumor xenograft models. Furthermore, the cys-diabody-PLN conjugate demonstrates target-specific binding of human pancreatic cancer cells with the potential to deliver targeted treatment.

BackgroundSensitive antibody-based tumor targeting has the potential not only to image metastatic and micrometastatic disease, but also to be the basis of targeted therapy. The vast majority of pancreas cancers express carcinoembryonic antigen (CEA). Thus, we sought to evaluate the potential of CEA as a pancreatic cancer target utilizing a rapidly clearing engineered anti-CEA scFv-Fc antibody fragment with a mutation in the Fc region [anti-CEA scFv-Fc H310A].MethodsImmunohistochemistry (IHC) with the antibody fragment was used to confirm expression of CEA on human pancreas cancer specimens. In vivo tumor targeting was evaluated by tail vein injection of I124-labeled anti-CEA scFv-Fc(H310A) into mice harboring CEA-positive and -negative xenografts. MicroPET/CT imaging was performed at successive time intervals. Radioactivity in blood and tumor was measured after the last time point. Additionally, unlabeled anti-CEA scFv-Fc(H310A) was injected into CEA-positive tumor bearing mice and ex vivo IHC was performed to identify the presence of the antibody to define the microscopic intratumoral pattern of targeting.ResultsModerate to strong staining by IHC was noted on 84% of our human pancreatic cancer specimens and was comparable to staining of our xenografts. Pancreas xenograft imaging with the radiolabeled anti-CEA scFv-Fc(H310A) antibody demonstrated average tumor/blood ratios of 4.0. Immunolocalization demonstrated peripheral antibody fragment penetration of one to five cell diameters (0.75 to 1.5 μm).ConclusionsWe characterized a preclinical xenograft model with respect to CEA expression that was comparable to human cases. We demonstrated that the anti-CEA scFv-Fc(H310A) antibody exhibited antigen-specific tumor targeting and shows promise as an imaging and potentially therapeutic agent.

Introduction. Sensitive and specific imaging of pancreas cancer are necessary for accurate diagnosis, staging, and treatment. The vast majority of pancreas cancers express the carbohydrate tumor antigen CA19-9. The goal of this study was to determine the potential to target CA19-9 with a radiolabeled anti-CA19-9 antibody for imaging pancreas cancer. Methods. CA19-9 was quantified using flow cytometry on human pancreas cancer cell lines. An intact murine anti-CA19-9 monoclonal antibody was labeled with a positron emitting radionuclide (Iodine-124) and injected into mice harboring antigen positive and negative xenografts. MicroPET/CT were performed at successive time intervals (72 hours, 96 hours, 120 hours) after injection. Radioactivity was measured in blood and tumor to provide objective confirmation of the images. Results. Antigen expression by flow cytometry revealed approximately 1.3 × 10(6) CA19-9 antigens for the positive cell line and no expression in the negative cell line. Pancreas xenograft imaging with Iodine-124-labeled anti-CA19-9 mAb demonstrated an average tumor to blood ratio of 5 and positive to negative tumor ratio of 20. Conclusion. We show in vivo targeting of our antigen positive xenograft with a radiolabeled anti-CA19-9 antibody. These data demonstrate the potential to achieve anti-CA19-9 antibody based positron emission tomography of pancreas cancer.

AJCC staging of pancreatic cancer (PAC) is used to determine prognosis, yet survival within each stage shows wide variation and remains unpredictable. We hypothesized that tumor grade might be responsible for some of this variation and that the addition of grade to current AJCC staging would provide improved prognostication.The Surveillance, Epidemiology, and End Results (SEER) database (1991–2005) was used to identify 8082 patients with resected PAC. The impact of grade on overall and stage-specific survival was assessed using Cox regression analysis. Variables in the model were age, sex, tumor size, lymph node status, and tumor grade.For each AJCC stage, survival was significantly worse for high-grade versus low-grade tumors. On multivariate analysis, high tumor grade was an independent predictor of survival for the entire cohort (hazard ratio [HR] 1.40, 95% confidence interval [95% CI] 1.31–1.48) as well as for stage I (HR 1.28, 95% CI 1.07–1.54), stage IIA (HR 1.43, 95% CI 1.26–1.61), stage IIB (HR 1.38, 95% CI 1.27–1.50), stage III (HR 1.28, 95% CI 1.02–1.59), and stage IV (HR 1.58, 95% CI 1.21–2.05) patients. The addition of grade to staging results in a statistically significant survival discrimination between all stages.Tumor grade is an important prognostic variable of survival in PAC. We propose a novel staging system incorporating grade into current AJCC staging for pancreas cancer. The improved prognostication is more reflective of tumor biology and may impact therapy decisions and stratification of future clinical trials.

BackgroundRheumatoid nodules are the most common extra-articular findings in patients with rheumatoid arthritis. They occur most commonly at pressure points such as the extensor surfaces of the forearms, fingers, and occiput, but have also been reported to occur in unusual locations including the central nervous system, pericardium, pleura, and sclera. We present the unusual case of rheumatoid nodules in the small bowel mesentery masquerading as an intra-abdominal malignancy.Case presentationA 65-year-old-male with a known history of longstanding erosive, nodular, seropositive rheumatoid arthritis was incidentally found to have a mesenteric mass on computed tomography (CT) exam of the abdomen. This mass had not been present on prior imaging studies and was worrisome for a malignancy. Attempts at noninvasive biopsy were nondiagnostic but consistent with a "spindle" cell neoplasm. Laparotomy revealed extensive thickening and fibrosis of the small bowel mesentery along with large, firm nodules throughout the mesentery. A limited bowel resection including a large, partially obstructing, nodule was performed. Pathology was consistent with an unusual presentation of rheumatoid nodules in the mesentery of the small bowel.ConclusionRheumatoid nodules should be considered in the differential diagnosis of a patient who presents with an intra-abdominal mass and a history of rheumatoid arthritis. Currently, no tests or imaging modality can discriminate with sufficient accuracy to rule out a malignancy in this difficult diagnostic delimma. Hopefully, this case will serve as impetus for further study and biomarker discovery to allow for improved diagnostic power.