Proposed diagnostic and prognostic markers of primary malignant hepatic vascular neoplasms

INTRODUCTION

Primary malignant hepatic vascular tumors with various malignant potentials include epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS), which may overlap pathologically. This study aimed to compare the pathological findings of hepatic EHE with those of AS, in association with patient outcomes.

METHODS

Fifty-nine histologically confirmed patients with 34 EHE and 25 AS were admitted to a tertiary hospital from 2003 to 2020. Their EHE and AS pathological features were compared. Immunohistochemistry for CD31, ERG, CAMTA-1, TFE3, P53, and Ki-67 labeling was performed on paraffin-embedded blocks. Markers, along with histological findings, were analyzed for the purposes of diagnostic and prognostic significance by multivariate analysis.

RESULTS

CAMTA-1 was 91.2% positive in EHE, but negative in AS (p = < 0.001). AS was significantly correlated to an aberrant p53 expression, high Ki-67 labeling, and high mitotic activity, compared to EHE (all, p = < 0.001). EHE can be classified as low grade (LG) and high grade (HG) using the prognostic values of mitotic activity and ki-67 labeling (sensitivity = 1, specificity = 1). Low grade-EHE showed significantly better overall survival than high grade-EHE (p = 0.020).

CONCLUSIONS

Immunohistochemistry for CAMTA-1, P53, and Ki-67 labeling may help distinguish EHE and AS in histologically ambiguous cases, especially small biopsied tissue. Moreover, the combination of mitotic activity and Ki-67 labeling can be a prognostic factor for EHE with various clinical features.

Clinical implication of the geometric location (fundal end versus cystic ductal end) of gallbladder cancer

BACKGROUND

Management of early-stage gallbladder cancer is becoming more important as the rate of early detection is increasing. Although there have been many studies about the clinical implication of the invasion depth or peritoneal/hepatic location of gallbladder cancers, there is no study on the clinical implication of the geometric location of cancer along the longitudinal length of the gallbladder.

METHODS

The location of gallbladder cancer was defined as the geometric center of the primary site of a tumour, which lies on the longitudinal diameter of the surgical specimens. We compared the oncologic outcomes following surgery between gallbladder cancers located on the fundal end and those located on the cystic ductal end. We also analysed patients with stage 1 gallbladder cancer who recurred after surgery.

RESULTS

A total of 575 patients with gallbladder cancer were included in this study. Patients with gallbladder cancer on the cystic ductal end had significantly lower rates of recurrence-free survival (P = 0.016) and overall survival (P = 0.023) compared to those with gallbladder cancer on the fundal end. Among 90 patients with stage 1 gallbladder cancer, three patients had a recurrence, all of whom had cystic ductal end gallbladder cancer and showed cystic duct invasion or concomitant xanthogranulomatous cholecystitis in permanent pathology.

CONCLUSIONS

Gallbladder cancers on the cystic ductal end had worse postoperative oncologic outcomes compared with those on the fundal end.

Characterization of lymphocyte-rich hepatocellular carcinoma and the prognostic role of tertiary lymphoid structures

BACKGROUND & AIMS

Lymphocyte-rich hepatocellular carcinoma (LR-HCC) is largely unknown and a rare subtype of HCC with immune-rich stroma. Tertiary lymphoid structures (TLS), frequently observed in LR-HCC, are known to be prognostically significant in various malignancies; however, their significance in HCC remains unevaluated.

METHODS

Clinicopathologic data of 191 cases of surgically resected conventional HCC (C-HCC, n = 160) and LR-HCC (n = 31) were retrieved. Immunohistochemistry, multiplex immunofluorescence staining, RNA sequencing and proteomic analysis were conducted. Differences between the subtypes were statistically evaluated.

RESULTS

LR-HCC was significantly correlated to larger tumour size, higher Edmondson-Steiner grade, presence of TLS and higher CD3-, CD8- and FOXP3-positive T cell, high PD-1 and PD-L1 expression (p < .001 for all) compared to C-HCC. Patients with LR-HCC exhibited significantly better overall survival (OS) (p = .044) and recurrence-free survival (RFS) (p = .025) than C-HCC. LR-HCC demonstrated TLS signatures with significantly higher proteomic-based immune scores in 14 of 17 types of tumour-infiltrating immune cells. Furthermore, C-HCC with secondary follicles, the most mature form of TLS, exhibited significantly better OS (p = .031) and RFS (p = .033) than those without. Across the global proteome, LR-HCC was well-differentiated from C-HCC and a map of protein-protein interactions between tumour-infiltrating lymphocytes and HCC in tumour microenvironment was completed.

CONCLUSION

LR-HCC is clinicopathologically and molecularly distinct and shows better prognosis compared to C-HCC. Also, the presence of secondary follicle can be an important prognostic marker for better prognosis in both LR-HCC and C-HCC.

A Circulating Panel of circRNA Biomarkers for the Noninvasive and Early Detection of Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies. Delayed manifestation of symptoms and lack of specific diagnostic markers lead patients being diagnosed with PDAC at advanced stages. This study aimed to develop a circular RNA (circRNA)-based biomarker panel to facilitate noninvasive and early detection of PDAC.

METHODS

A systematic genome-wide discovery of circRNAs overexpressed in patients with PDAC was conducted. Subsequently, validation of the candidate markers in the primary tumors from patients with PDAC was performed, followed by their translation into a plasma-based liquid biopsy assay by analyzing 2 independent clinical cohorts of patients with PDAC and nondisease controls. The performance of the circRNA panel was assessed in conjunction with the plasma levels of cancer antigen 19-9 for the early detection of PDAC.

RESULTS

Initially, a panel of 10 circRNA candidates was identified during the discovery phase. Subsequently, the panel was reduced to 5 circRNAs in the liquid biopsy-based assay, which robustly identified patients with PDAC and distinguished between early-stage (stage I/II) and late-stage (stage III/IV) disease. The areas under the curve of this diagnostic panel for the detection of early-stage PDAC were 0.83 and 0.81 in the training and validation cohorts, respectively. Moreover, when this panel was combined with cancer antigen 19-9 levels, the diagnostic performance for identifying patients with PDAC improved remarkably (area under the curve, 0.94) for patients in the validation cohort. Furthermore, the circRNA panel could also efficiently identify patients with PDAC (area under the curve, 0.85) who were otherwise deemed clinically cancer antigen 19-9-negative (<37 U/mL).

CONCLUSIONS

A circRNA-based biomarker panel with a robust noninvasive diagnostic potential for identifying patients with early-stage PDAC was developed.

Evaluation of postoperative outcomes of minimally invasive distal pancreatectomy for left-sided pancreatic tumors based on the modified frailty index: a retrospective cohort study

BACKGROUND

This study compared the postoperative outcomes of minimally invasive distal pancreatectomy (MIDP) for left-sided pancreatic tumors based on the modified frailty index (mFI).

MATERIALS AND METHODS

This retrospective study included 2212 patients who underwent MIDP for left-sided pancreatic tumors between 2005 and 2019. Postoperative outcomes, including complications (morbidity and mortality), were analyzed using mFI, and the participants were divided into two groups: frail ( n =79) and nonfrail ( n =2133). A subanalysis of 495 MIDPs for pancreatic ductal adenocarcinoma was conducted to compare oncological outcomes.

RESULTS

Clinically relevant postoperative pancreatic fistula was significantly higher in the frail group than in the nonfrail group. A significant between-group difference was observed in overall complications with Clavien-Dindo classification grade ≥III. Furthermore, the proportion of all complications before readmission was higher in the frail group than in the nonfrail group. Among all readmitted patients, the frail group had a higher number of grade ≥IV patients requiring ICU treatment. The frail group's 90-day mortality was 1.3%; the difference was statistically significant (nonfrail: 0.3%, P =0.021). In the univariate and multivariate logistic regression analyses, mFI ≥0.27 (odds ratio 3.231, 95% CI: 1.889-5.523, P <0.001), extended pancreatectomy, BMI ≥30 kg/m 2 , male sex, and malignancy were risk factors for Clavien-Dindo classification grade ≥III.

CONCLUSION

mFI is a potential preoperative tool for predicting severe postoperative complications, including mortality, in patients who have undergone MIDP for left-sided tumors.

Intercellular cross-talk through lineage-specific gap junction of cancer-associated fibroblasts related to stromal fibrosis and prognosis

Stromal fibrosis in cancer is usually associated with poor prognosis and chemotherapy resistance. It is thought to be caused by fibroblasts; however, the exact mechanism is not yet well understood. The study aimed to identify lineage-specific cancer-associated fibroblast (CAF) subgroup and their associations with extracellular matrix remodeling and clinical significances in various tumor types using single-cell and bulk RNA sequencing data. Through unsupervised clustering, six subclusters of CAFs were identified, including a cluster with exclusively high gap junction protein beta-2 (GJB2) expression. This cluster was named GJB2-positive CAF. It was found to be a unique subgroup of terminally differentiated CAFs associated with collagen gene expression and extracellular matrix remodeling. GJB2-positive CAFs showed higher communication frequency with vascular endothelial cells and cancer cells than GJB2-negative CAFs. Moreover, GJB2 was poorly expressed in normal tissues, indicating that its expression is dependent on interaction with other cells, including vascular endothelial cells and cancer cells. Finally, the study investigated the clinical significance of GJB2 signature score for GJB2-positive CAFs in cancer and found a correlation with poor prognosis. These results suggest that GJB2-positive CAF is a unique fibroblast subtype involved in extracellular matrix remodeling, with significant clinical implications in cancer.

Orthotopic model of pancreatic cancer using CD34+ humanized mice and generation of tumor organoids from humanized tumors

In pancreatic cancer (PC) as intractable solid cancer, current research is focused mainly on targeted immunotherapies such as antibodies and immune cell modulators. To identify promising immune-oncological agents, animal models that recapitulate the essential features of human immune status are essential. To this end, we constructed an orthotopic xenograft model using CD34⁺ human hematopoietic stem cell-based humanized NOD scid gamma mouse (NSG) mice injected with luciferase-expressing PC cell lines AsPC1 and BxPC3. The growth of orthotopic tumors was monitored using noninvasive multimodal imaging, while the subtype profiles of human immune cells in blood and tumor tissues were determined by flow cytometry and immunohistopathology. In addition, the correlations of blood and tumor-infiltrating immune cell count with tumor extracellular matrix density were calculated using Spearman's test. Tumor-derived cell lines and tumor organoids with continuous passage capacity in vitro were isolated from orthotopic tumors. It was further confirmed that these tumor-derived cells and organoids have reduced PD-L1 expression and are suitable for testing the efficacy of specific targeted immunotherapeutic agents. These animal and culture models could facilitate the development and validation of immunotherapeutic agents for intractable solid cancers including PC.

Integrative modeling of tumor genomes and epigenomes for enhanced cancer diagnosis by cell-free DNA

Multi-cancer early detection remains a key challenge in cell-free DNA (cfDNA)-based liquid biopsy. Here, we perform cfDNA whole-genome sequencing to generate two test datasets covering 2125 patient samples of 9 cancer types and 1241 normal control samples, and also a reference dataset for background variant filtering based on 20,529 low-depth healthy samples. An external cfDNA dataset consisting of 208 cancer and 214 normal control samples is used for additional evaluation. Accuracy for cancer detection and tissue-of-origin localization is achieved using our algorithm, which incorporates cancer type-specific profiles of mutation distribution and chromatin organization in tumor tissues as model references. Our integrative model detects early-stage cancers, including those of pancreatic origin, with high sensitivity that is comparable to that of late-stage detection. Model interpretation reveals the contribution of cancer type-specific genomic and epigenomic features. Our methodologies may lay the groundwork for accurate cfDNA-based cancer diagnosis, especially at early stages.

Abstract 6697: Deep learning algorithm for cancer detection using multimodal characteristics of whole methylome sequencing of cf-DNA

Background Various cell-free DNA (cfDNA) features including methylation and genomic profiles have been investigated for their potential use in early cancer detection. We developed deep learning models based the data generated by the enzymatic conversion based whole methylome sequencing of cfDNA.

Methods Cell-free whole genome Enzymatic Methyl sequencing(cfWEMseq) data were generated from 198 cancer patients (stage I: 11%, II: 17%, III: 22%, IV: 20%, unknown: 31%) and 69 healthy controls. The cancer types were consisted of breast (n=31), liver (n=24), esophageal (n=38), pancreatic (n=30), colon (n=34), ovarian (n=18), and lung (n=23). Sequence data was produced on average of 200 million reads using Novaseq 6000 (Illumina). For model training and evaluation, data partitioning was stratified by cancer type, and 5-fold cross validation was used. Coverage and methylation beta values ​​were calculated by binning at fixed size of 100K, 1M, and 5M base and variable size from Topologically Associated Domains (TAD). Genome Coverage (GC), Genome Methylation Beta values ​​(GMB), and Mutation Signature (MS) features were trained using a one-dimensional convolutional neural network (1D-CNN). The performance of the model was evaluated by measuring the average value of the results measured in each test set of 5 fold.

Results We tested the cancer detection performance of various feature combinations using all data from cfWEMseq (n=267). Regardless of the bin size, the GMB single model achieved higher performance than the GC single model. The best-performing model is the ensemble model of GMB (100k bin) and MS. The cancer detection performance of this ensemble model reached an accuracy 96% (CI: 93.6% to 98.1%), AUC 0.99 (CI: 0.97 to 1.0) and sensitivity 98.0% (CI: 92.4% to 99.5%) with a specificity of 90%.

Conclusions These results provide an opportunity for higher accuracies by integrating methylation information and genomic data using cfWEMseq. This research was supported through the National Research Foundation (NRF) funded by the Ministry of Science and ICT (2020M2D9A3094213).

Citation Format: Juntae Park, Minjung Kim, Sook Ryun Park, Ki-Byung Song, Eunsung Jun, Dongryul Oh, Jeong-Won Lee, Young Sik Park, Ki-Won Song, Jeong-Sik Byeon, Bo Hyun Kim, Chang-Seok Ki, Eunhae Cho. Deep learning algorithm for cancer detection using multimodal characteristics of whole methylome sequencing of cf-DNA. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6697.

Synergistic therapeutic combination with a CAF inhibitor enhances CAR-NK-mediated cytotoxicity via reduction of CAF-released IL-6

BACKGROUND

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) contribute to an impaired functionality of natural killer (NK) cells that have emerged as a promising therapeutic modality. The interaction between CAFs and NK cells within the TME exerts major inhibitory effects on immune responses, indicating CAF-targeted therapies as potential targets for effective NK-mediated cancer killing.

METHODS

To overcome CAF-induced NK dysfunction, we selected an antifibrotic drug, nintedanib, for synergistic therapeutic combination. To evaluate synergistic therapeutic efficacy, we established an in vitro 3D Capan2/patient-derived CAF spheroid model or in vivo mixed Capan2/CAF tumor xenograft model. The molecular mechanism of NK-mediated synergistic therapeutic combination with nintedanib was revealed through in vitro experiments. In vivo therapeutic combination efficacy was subsequently evaluated. Additionally, the expression score of target proteins was measured in patient-derived tumor sections by the immunohistochemical method.

RESULTS

Nintedanib blocked the platelet-derived growth factor receptor β (PDGFRβ) signaling pathway and diminished the activation and growth of CAFs, markedly reducing CAF-secreted IL-6. Moreover, coadministration of nintedanib improved the mesothelin (MSLN) targeting chimeric antigen receptor-NK-mediated tumor killing abilities in CAF/tumor spheroids or a xenograft model. The synergistic combination resulted in intense NK infiltration in vivo. Nintedanib alone exerted no effects, whereas blockade of IL-6 trans-signaling ameliorated the function of NK cells. The combination of the expression of MSLN and the PDGFRβ⁺-CAF population area, a potential prognostic/therapeutic marker, was associated with inferior clinical outcomes.

CONCLUSION

Our strategy against PDGFRβ⁺-CAF-containing pancreatic cancer allows improvements in the therapy of pancreatic ductal adenocarcinoma.

Laparoscopic versus open pancreaticoduodenectomy with major vein resection for pancreatic head cancer

BACKGROUND/PURPOSE

Laparoscopic pancreaticoduodenectomy (PD) with major vein resection is a challenging procedure. Herein, we evaluated the feasibility and safety of laparoscopic vein resection in pancreatic head cancer with portal vein/superior mesenteric vein (PV/SMV) invasion, and compared the survival rate following laparoscopic surgery with that following open surgery.

METHODS

We retrospectively reviewed the electronic medical records of all patients with pancreatic head cancer who underwent surgery performed by a single surgeon from January 2015 to December 2017. Kaplan-Meier curves were plotted to compare the disease-free survival, while Cox-proportional hazard models were used to analyze prognostic factors for survival.

RESULTS

Among 76 patients, 63 underwent open PD and 13 underwent laparoscopic PD with PV/SMV resection. There was no significant difference in the rate of complications, including portal vein stenosis and portal vein thrombus, recurrence of tumors, or pathological outcomes after surgery between the groups. There was also no significant difference in disease-free survival (p = .803) between the two groups. Additionally, the surgical method was not an independent prognostic factor for disease-free survival.

CONCLUSIONS

Laparoscopic PD with major vein resection can be feasibly performed in select patients with abutment and focal narrowing of the PV/SMV in pancreatic head cancer.

Minimally invasive versus open pancreaticoduodenectomy for distal bile duct cancer: an inverse probability of treatment weighting analysis of outcomes

BACKGROUND

Minimally invasive pancreaticoduodenectomy (MIPD) has been extended to periampullary cancers, but the oncologic outcome of MIPD for distal bile duct cancer (DBDC) has not been confirmed yet.

METHODS

Patients who underwent pancreaticoduodenectomy (PD) for DBDC of stage I-IIb from 2015 to 2019 at a tertiary referral center were identified and divided into open PD (OPD) and MIPD groups, the latter including laparoscopic and robotic procedures. Survival was compared between the two groups after inverse probability of treatment weighting (IPTW) using predetermined factors, and exploratory mediation analysis was performed using surgery-derived outcomes.

RESULTS

MIPD (n = 81) group had more female patients (46.9% vs 31.6%, p = 0.011) and longer operation time (366.2 min vs. 279.1 min, p < 0.001) than the OPD (n = 288) group before IPTW. Otherwise, intraoperative and immediate postoperative outcomes were comparable between the two groups. In oncologic outcomes, MIPD group showed comparable 3-year overall survival (78.2% vs 75.0%, p = 0.062) and recurrence-free survival (51.2% vs 53.4%, p = 0.871) rates with OPD group before IPTW, and MIPD was not related with survival (hazard ratio [HR] 0.61, 95% confidence interval [CI] 0.29-1.26, p = 0.18) and recurrence (HR 1.01, 95% CI 0.67-1.53, p = 0.949) after IPTW with consideration of potential mediators. Sensitivity analysis using propensity score matching also showed similar results for survival (HR 0.68, 95% CI 0.32-1.44, p = 0.312) and recurrence (HR 1.12, 95% CI 0.67-1.88, p = 0.653).

CONCLUSION

MIPD and OPD groups showed similar postoperative and oncologic outcomes. MIPD could be a considerable treatment option without oncological compromise in high-volume centers.

Multi-biomarker panel prediction model for diagnosis of pancreatic cancer

BACKGROUND/PURPOSE

The current study aimed to develop a prediction model using a multi-marker panel as a diagnostic screening tool for pancreatic ductal adenocarcinoma.

METHODS

Multi-center cohort of 1991 blood samples were collected from January 2011 to September 2019, of which 609 were normal, 145 were other cancer (colorectal, thyroid, and breast cancer), 314 were pancreatic benign disease, and 923 were pancreatic ductal adenocarcinoma. The automated multi-biomarker Enzyme-Linked Immunosorbent Assay kit was developed using three potential biomarkers: LRG1, TTR, and CA 19-9. Using a logistic regression model on a training data set, the predicted values for pancreatic ductal adenocarcinoma were obtained, and the result was classification into one of the three risk groups: low, intermediate, and high. The five covariates used to create the model were sex, age, and three biomarkers.

RESULTS

Participants were categorized into four groups as normal (n = 609), other cancer (n = 145), pancreatic benign disease (n = 314), and pancreatic ductal adenocarcinoma (n = 923). The normal, other cancer, and pancreatic benign disease groups were clubbed into the non-pancreatic ductal adenocarcinoma group (n = 1068). The positive and negative predictive value, sensitivity, and specificity were 94.12, 90.40, 93.81, and 90.86, respectively.

CONCLUSIONS

This study demonstrates a significant diagnostic performance of the multi-marker panel in distinguishing pancreatic ductal adenocarcinoma from normal and benign pancreatic disease states, as well as patients with other cancers.

Transcriptomic Profiling Identifies an Exosomal microRNA Signature for Predicting Recurrence Following Surgery in Patients With Pancreatic Ductal Adenocarcinoma

OBJECTIVE

We performed genome-wide expression profiling to develop an exosomal miRNA panel for predicting recurrence following surgery in patients with PDAC.

SUMMARY OF BACKGROUND DATA

Pretreatment risk stratification is essential for offering individualized treatments to patients with PDAC, but predicting recurrence following surgery remains clinically challenging.

METHODS

We analyzed 210 plasma and serum specimens from 4 cohorts of PDAC patients. Using a discovery cohort (n = 25), we performed genome-wide sequencing to identify candidate exosomal miRNAs (exo-miRNAs). Subsequently, we trained and validated the predictive performance of the exo-miRNAs in two clinical cohorts (training cohort: n = 82, validation cohort: n = 57) without neoadjuvant therapy (NAT), followed by a post-NAT clinical cohort (n = 46) as additional validation.

RESULTS

We performed exo-miRNA expression profiling in plasma specimens obtained before any treatment in a discovery cohort. Subsequently we optimized and trained a 6-exo-miRNA risk-prediction model, which robustly discriminated patients with recurrence [area under the curve (AUC): 0.81, 95% confidence interval (CI): 0.70-0.89] and relapse-free survival (RFS, P < 0.01) in the training cohort. The identified exo-miRNA panel was successfully validated in an independent validation cohort (AUC: 0.78, 95% CI: 0.65- 0.88, RFS: P < 0.01), where it exhibited comparable performance in the post-NAT cohort (AUC: 0.72, 95% CI: 0.57-0.85, RFS: P < 0.01) and emerged as an independent predictor for RFS (hazard ratio: 2.84, 95% CI: 1.30-6.20).

CONCLUSIONS

We identified a novel, noninvasive exo-miRNA signature that robustly predicts recurrence following surgery in patients with PDAC; highlighting its potential clinical impact for optimized patient selection and improved individualized treatment strategies.

An Exosome-based Transcriptomic Signature for Noninvasive, Early Detection of Patients With Pancreatic Ductal Adenocarcinoma: A Multicenter Cohort Study

BACKGROUND & AIMS

Pancreatic ductal adenocarcinoma (PDAC) incidence is rising worldwide, and most patients present with an unresectable disease at initial diagnosis. Measurement of carbohydrate antigen 19-9 (CA19-9) levels lacks adequate sensitivity and specificity for early detection; hence, there is an unmet need to develop alternate molecular diagnostic biomarkers for PDAC. Emerging evidence suggests that tumor-derived exosomal cargo, particularly micro RNAs (miRNAs), offer an attractive platform for the development of cancer-specific biomarkers. Herein, genomewide profiling in blood specimens was performed to develop an exosome-based transcriptomic signature for noninvasive and early detection of PDAC.

METHODS

Small RNA sequencing was undertaken in a cohort of 44 patients with an early-stage PDAC and 57 nondisease controls. Using machine-learning algorithms, a panel of cell-free (cf) and exosomal (exo) miRNAs were prioritized that discriminated patients with PDAC from control subjects. Subsequently, the performance of the biomarkers was trained and validated in independent cohorts (n = 191) using quantitative reverse transcription polymerase chain reaction (qRT-PCR) assays.

RESULTS

The sequencing analysis initially identified a panel of 30 overexpressed miRNAs in PDAC. Subsequently using qRT-PCR assays, the panel was reduced to 13 markers (5 cf- and 8 exo-miRNAs), which successfully identified patients with all stages of PDAC (area under the curve [AUC] = 0.98 training cohort; AUC = 0.93 validation cohort); but more importantly, was equally robust for the identification of early-stage PDAC (stages I and II; AUC = 0.93). Furthermore, this transcriptomic signature successfully identified CA19-9 negative cases (<37 U/mL; AUC = 0.96), when analyzed in combination with CA19-9 levels, significantly improved the overall diagnostic accuracy (AUC = 0.99 vs AUC = 0.86 for CA19-9 alone).

CONCLUSIONS

In this study, an exosome-based liquid biopsy signature for the noninvasive and robust detection of patients with PDAC was developed.

Direct cell-to-cell transfer in stressed tumor microenvironment aggravates tumorigenic or metastatic potential in pancreatic cancer

Pancreatic cancer exhibits a characteristic tumor microenvironment (TME) due to enhanced fibrosis and hypoxia and is particularly resistant to conventional chemotherapy. However, the molecular mechanisms underlying TME-associated treatment resistance in pancreatic cancer are not fully understood. Here, we developed an in vitro TME mimic system comprising pancreatic cancer cells, fibroblasts and immune cells, and a stress condition, including hypoxia and gemcitabine. Cells with high viability under stress showed evidence of increased direct cell-to-cell transfer of biomolecules. The resulting derivative cells (CD44^high/SLC16A1^high) were similar to cancer stem cell-like-cells (CSCs) with enhanced anchorage-independent growth or invasiveness and acquired metabolic reprogramming. Furthermore, CD24 was a determinant for transition between the tumorsphere formation or invasive properties. Pancreatic cancer patients with CD44^low/SLC16A1^low expression exhibited better prognoses compared to other groups. Our results suggest that crosstalk via direct cell-to-cell transfer of cellular components foster chemotherapy-induced tumor evolution and that targeting of CD44 and MCT1(encoded by SLC16A1) may be useful strategy to prevent recurrence of gemcitabine-exposed pancreatic cancers.

Prediction the clinical EPR effect of nanoparticles in patient-derived xenograft models

Many preclinically tested nanoparticles in existing animal models fail to be directly translated into clinical applications because of their poor resemblance to human cancer. Herein, the enhanced permeation and retention (EPR) effect of glycol chitosan nanoparticles (CNPs) in different tumor microenvironments (TMEs) was compared using different pancreatic tumor models, including pancreatic cancer cell line (BxPC3), patient-derived cancer cell (PDC), and patient-derived xenograft (PDX) models. CNPs were intravenously injected into different tumor models, and their accumulation efficiency was evaluated using non-invasive near-infrared fluorescence (NIRF) imaging. In particular, differences in angiogenic vessel density, collagen matrix, and hyaluronic acid content in tumor tissues of the BxPC3, PDC, and PDX models greatly affected the tumor-targeting efficiency of CNPs. In addition, different PDX models were established using different tumor tissues of patients to predict the clinical EPR effect of CNPs in inter-patient TMEs, wherein the gene expression levels of PECAM1, COL4A1, and HAS1 in human tumor tissues were observed to be closely related to the EPR effect of CNPs in PDX models. The results suggested that the PDX models could mimic inter-patient TMEs with different blood vessel structures and extracellular matrix (ECM) content that critically affect the tumor-targeting ability of CNPs in different pancreatic PDX models. This study provides a better understanding of the heterogeneity and complexity of inter-patient TMEs that can predict the response of various nanoparticles in individual tumors for personalized cancer therapy.

Preoperative data-based deep learning model for predicting postoperative survival in pancreatic cancer patients

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis even after curative resection. A deep learning-based stratification of postoperative survival in the preoperative setting may aid the treatment decisions for improving prognosis. This study was aimed to develop a deep learning model based on preoperative data for predicting postoperative survival.

METHODS

The patients who underwent surgery for PDAC between January 2014 and May 2015. Clinical data-based machine learning models and computed tomography (CT) data-based deep learning models were developed separately, and ensemble learning was utilized to combine two models. The primary outcomes were the prediction of 2-year overall survival (OS) and 1-year recurrence-free survival (RFS). The model's performance was measured by area under the receiver operating curve (AUC) and was compared with that of American Joint Committee on Cancer (AJCC) 8th stage.

RESULTS

The median OS and RFS were 23 and 10 months in training dataset (n = 229), and 22 and 11 months in test dataset (n = 53), respectively. The AUC of the ensemble model for predicting 2-year OS and 1-year RFS in the test dataset was 0.76 and 0.74, respectively. The performance of the ensemble model was comparable to that of the AJCC in predicting 2-year OS (AUC, 0.67; P = 0.35) and superior to the AJCC in predicting 1-year RFS (AUC, 0.54; P = 0.049).

CONCLUSION

and relevance: Our ensemble model based on routine preoperative variables showed good performance for predicting prognosis for PDAC patients after surgery.

Abstract 6371: Deep learning algorithm for multi-cancer detection and classification using cf-WGS

Purpose: Several cell-free DNA (cf-DNA) features, such as genome-wide coverage, fragment size, and fragment end motif frequency, have shown their potentials for cancer detection. In this study, we developed two independent models, GC (gross chromatin), and FEMS (fragment end motif frequency and size). Each model uses images generated from genome-wide normalized sequencing coverage and cf-DNA fragment end motif frequencies according to the different cf-DNA size profiles. Then we integrated them into a single ensemble model to improve cancer detection and multi-cancer type classification accuracy.

Methods: Low depth cf-WGS data was generated from 1,396 patients (stage I: 14.9%, stage II: 35.6%, stage III: 24.9%, stage IV: 24.2%, unknown: 0.4%) with breast (n=702), liver (n=213), esophageal (n=155), ovarian (n=151), pancreatic (n=85), lung (n=53), head and neck (n=16), biliary tract (n=15), and colon cancer (n=6) and 417 healthy individuals. Samples were randomly split into training, validation, and test set stratifying cancer type and stages. Cancer types with a small number of samples (&lt;20) were excluded for multi-cancer type classification. Each model was trained using a convolutional neural network, then integrated into a single ensemble model by averaging the predicted probabilities calculated from each model.

Results: For cancer detection, the ensemble model achieved sensitivities of 85.2% [95% confidence interval (CI): 71.8% to 94.5%], 74.9% (CI: 68.0% to 88.0%), 73.2% (CI: 66.7% to 85.9%) at a specificity of 95%, 98% and 99% and the AUC value of 0.97(CI: 0.95-0.99) in the test dataset. By the cancer stages, sensitivity was 62.8% (CI: 48.8% to 83.7%) in stage I, 66.3% (CI: 57.7% to 82.7%) in stage II, 85.9% (CI: 77.5% to 94.4%) in stage III, and 76.1% (CI: 63.4% to 87.3%) in stage IV at 99% specificity. For multi-cancer classification, the overall accuracy of 85.1% (CI: 80.4% to 89.3%) was achieved including 6 cancer types.

Conclusions: Highly sensitive and accurate deep learning model for cancer detection and multi-cancer classification was generated by combining different types of cf-DNA features. This result provides the opportunity for general population multi-cancer screening using various cf-DNA features.

Citation Format: Tae-Rim Lee, Jin Mo Ahn, Joo Hyuk Sohn, Sook Ryun Park, Min Hwan Kim, Gun Min Kim, Ki-Byung Song, Eunsung Jun, Dongryul Oh, Jeong-Won Lee, Joseph J Noh, Young Sik Park, Sun-Young Kong, Sang Myung Woo, Bo Hyun Kim, Eui Kyu Chie, Hyun-Cheol Kang, Youn Jin Choi, Ki-Won Song, Jeong-Sik Byeon, Junnam Lee, Dasom Kim, Chang-Seok Ki, Eunhae Cho. Deep learning algorithm for multi-cancer detection and classification using cf-WGS [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6371.

Abstract 3389: An exosomal miRNA-based liquid biopsy signature for the noninvasive early detection of pancreatic ductal adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC) is projected to become the second leading cause of cancer-related deaths in the United States by 2030. Most of the PDAC patients are diagnosed with advanced disease, and less than 20% of patients are resectable at the time of diagnosis. The current imaging tools and blood markers (e.g. CA 19-9), are inadequate for early disease detection due to their poor specificity and sensitivity. This highlights the need to develop robust, noninvasive biomarkers for early detection of PDAC. While a large body of literature supports the use of cell-free miRNAs (cf-miRNAs) as potential diagnostic biomarkers in cancer, their tumor specificity is often debatable. Given the emerging evidence that exosomal cargo is a more robust representation of individual tumor types, in this study we sought to explore the diagnostic potential of cf-miRNAs along with exosomal miRNAs (exo-miRNAs), to establish a non-invasive miRNA signature for the early detection of PDAC.

Methods: As part of the NCI’s Pancreatic Cancer Detection Consortium (PCDC) funded project, in this study, small RNA-sequencing was performed in exosome and cell-free (cf) samples from a cohort of 57 PDAC cases and 57 non-disease controls. Using rigorous bioinformatic and biostatistical approaches, we prioritized a panel of cf- and exo-miRNAs and evaluated its diagnostic performance in the sequencing-based discovery and validation cohorts. Subsequently, the performance of the discovered miRNA panel was validated using qRT-PCR assays in an independent clinical validation cohort of PDAC patients and non-disease controls (n=48/each group). The results were examined by ROC curve analysis to determine the diagnostic power of the biomarker panel individually and in combination for their ability to discriminate PDAC from controls.

Results: The genomewide transcriptomic analyses led to the identification of a panel of 13 cf-miRNA and 17 exo-miRNA candidates. Sequencing validation in an independent cohort revealed that a combined panel of cf and exo-miRNAs exhibited an area under curve (AUC) of 0.89. Subsequent risk score analysis demonstrated that our biomarker signature was also robust in the identification of PDAC patients with early-stage cancers (stage I & II) vs. controls (p &lt;0.001). Moreover, when we combined the miRNA biomarker panel with CA19-9 values, the diagnostic performance was significantly superior when compared to the biomarker panel alone. Finally, the validation efforts in clinical cohorts by qRT-PCR revealed that the combined miRNA panel yielded an impressive accuracy with an AUC of 0.91, and a sensitivity of 0.88 and specificity of 0.87.

Conclusions: In conclusion, we report a novel, exosome-based miRNA signature for the early detection of patients with PDAC; which could potentially improve early-detection efforts for this fatal malignancy.

Citation Format: Kota Nakamura, Souvick Roy, Zhongxu Zhu, Eunsung Jun, Haiyong Han, Ruben M. Munoz, Satoshi Nishiwada, Geeta Sharma, Derek Cridebring, Frederic Zenhausern, Seungchan Kim, Denise Roe, Sourat Darabi, In Woong Han, Douglas Evans, Suguru Yamada, Michael Demure, Scott A. Celinski, Erkut Borazanci, Susan Tsai, John Bolton, Yasuhiro Kodera, Joon Oh Park, Song Cheol Kim, Xin Wang, Daniel Von Hoff, Ajay Goel. An exosomal miRNA-based liquid biopsy signature for the noninvasive early detection of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3389.

Sensitive detection of cancer using deep learning model of cfDNA genome-wide methylation data

e18789

Background: Methylation analysis of cfDNA has been used to diagnose cancer in its early stages. Previous research has concentrated on local methylation signals using cancer type specific methylation markers. We used not just methylation markers, but also global methylation patterns for sensitive cancer detection. Methods: We generated methylation data from cancer patients (N = 717) and normal controls (N = 190) using cell-free methylated DNA immunoprecipitation and high-throughput sequencing (cfMeDIP-seq, N = 907) and cell free whole genome enzymatic methyl seq (cfWGEM-seq, N = 162) from cancer patients (N = 137) and normal controls (N = 25). We analyzed at the Illumina 450K methylation microarray (N = 3,479) from The Cancer Genome Atlas (TCGA) to find differentially methylated regions (DMR) in 6 cancer types (breast, lung, liver, ovarian, esophageal, and pancreatic cancer). After determining the overlapping DMRs of each dataset, the best 1661 regions that differed the most between the cancer patient group and the normal group were left. The selected marker-based model was cross-validated using cfMeDIP samples separated into training, validation, and test sets. Additionally, global methylation count values of cfMeDIP-seq data were used to train convolutional neural network. Finally, the global methylation pattern deep learning algorithm and the marker-based algorithm were combined to detect cancer. Results: Deep learning models based on selected markers and global methylation patterns achieved test data accuracy of 0.88-0.92 and 0.90-0.91, respectively, with AUC 0.94-0.96 and 0.95-0.96. The ensemble model of two models showed test data accuracy 0.91-0.92 and AUC 0.96-0.97 with the detection of early stage of cancers (stage 1:detection rate of 88-100%, stage 2:detection rate of 75-100%, stage 3:detection rate of 90-97%, stage 4:detection rate of 92-100%). Conclusions: In this study, we selected best markers by using tissue methylation dataset (TCGA) and cfDNA methylation datasets (cfMeDIP-seq, cfWGEM-seq). To train cancer detection models, we used not only the DMR pattern but also the global methylation pattern. And the ensemble model that included these features outperformed a single model. In the field of early cancer detection, our models show potential.

Minimally invasive distal pancreatectomy: Chronologic changes in the trends and clinical outcomes through a 15-year, single-center experience with 2212 patients

BACKGROUND

We identified the chronologic changes in the clinical outcomes of minimally invasive distal pancreatectomy (MIDP) for left-sided pancreatic tumors in a single high-volume center over a period of 15 years.

METHODS

Between 2005 and 2019, 2212 patients underwent planned MIDP. Chronologic changes were analyzed according to 5-year intervals (P1, P2, P3). Furthermore, we assessed the prognostic factors of open conversion and postoperative complications.

RESULTS

MIDP has steadily increased during the last 15 years when compared to open distal pancreatectomy, from 10.8% to 84.9%. Also, MIDP for pancreatic ductal adenocarcinoma (PDAC) has been steadily increasing from 5.6% to 68.4%. According to the 5-year intervals, lengths of hospital stay decreased, but age and American Society of Anesthesiologists (ASA) ≥3 increased; conversely, the rates of Clavien-Dindo classification ≥grade 3 (9.5%) and postoperative pancreatic fistula (39.7%) showed no differences. The 90-day mortality and open conversion rates were 0.2% and 3.5%, respectively. Multivariate logistic regression analysis revealed malignancy and extended pancreatectomy were risk factors for open conversion. Furthermore, the poor prognostic factors for severe complications were malignancy, extended pancreatectomy, and ASA ≥3.

CONCLUSION

MIDP has become a popular procedure not only for benign cases but also for malignant ones. However, well-organized training, experience and skill are necessary, especially for poor-performance patients and extensively malignant conditions.

Controversial benefit of 5-fluorouracil/leucovorin-based adjuvant chemotherapy for ampullary cancer: a propensity score-matched analysis

BACKGROUND

Although surgery is the primary treatment for ampullary cancer (AC), the benefit of adjuvant chemotherapy (CTx) has not yet been confirmed.

METHODS

AC patients who were administered 5-fluorouracil(FU)/leucovorin(LV)-based CTx after curative intent surgery between 2011 and 2019 were included. Prognosis was compared between the observation (OB) and CTx groups after propensity score matching (PSM) using perioperative variables to control differences in patient characteristics.

RESULTS

Before PSM, of 475 patients, those in the CTx group (n = 281) had worse 5-year overall survival (OS) (82.1% vs. 78.5%, p = 0.017) and worse 5-year recurrence-free survival (RFS) (54.9% vs. 75.7%, p < 0.001) than those in the OB group (n = 194). In addition, the CTx group had a higher rate of poor prognostic factors such as a high T stage (p < 0.001), node metastasis (p < 0.001), and poor differentiation (p < 0.001). After PSM, perioperative outcomes were comparable. In addition, there were no significant differences in OS (hazard ratio [HR], 1.085; 95% confidence interval [CI], 0.688-1.710; p = 0.726) or RFS (HR, 0.883; 95% CI, 0.613 1.272; p = 0.505) between the CTx (n = 123) and OB (n = 123) groups even after stratification by TNM stage. Intestinal subtype showed better 5-year OS (83.7% vs 33.2%, p = 0.015) and RFS (46.5% vs 24.9%, p = 0.035) rate compared with pancreatobiliary/mixed subtype.

CONCLUSION

Patients who received adjuvant chemotherapy based on 5-FU/LV showed comparable oncologic outcomes to patients in the OB group even after stratification by tumor stage. The patients with intestinal subtype showed oncologic benefit for adjuvant 5-FU/LV CTx compared with pancreatobiliary or mixed subtypes.

Facile discovery of a therapeutic agent for NK-mediated synergistic antitumor effects using a patient-derived 3D platform

Despite the essential roles of natural killer (NK) cells in cancer treatment, the physical barrier and biological cues of the tumor microenvironment (TME) may induce NK cell dysfunction, causing their poor infiltration into tumors. The currently available two-dimensional (2D) cancer-NK co-culture systems hardly represent the characteristics of TME and are not suitable for tracking the infiltration of immune cells and assessing the efficacy of immunotherapy. This study aims to monitor NK-mediated cancer cell killing using a polymer thin film-based, 3D assay platform that contains highly tumorigenic cancer spheroids. A poly(cyclohexyl methacrylate) (pCHMA)-coated surface enables the generation of tumorigenic spheroids from pancreatic cancer patient-derived cancer cells, showing considerable amounts of extracellular matrix (ECM) proteins and cancer stem cell (CSC)-like characteristics. The 3D spheroid-based assay platform allows rapid discovery of a therapeutic agent for synergistic NK-mediated cytotoxicity through imaging-based high-content screening. In detail, the small molecule C19, known as a multi-epithelial-mesenchymal transition pathway inhibitor, is shown to enhance NK activation and infiltration via modulation of the ECM, resulting in synergistic cytotoxicity against cancer spheroids. This 3D biomimetic co-culture assay platform provides promising applications for predicting patient-specific responses to immunotherapy through advanced therapeutic combinations involving a chemical drug and immune cells.

Preoperative serum carbohydrate antigen 19-9 levels predict early recurrence after the resection of early-stage pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a serious disease with a poor prognosis. Only a minority of patients undergo surgery due to the advanced stage of the disease, and patients with early-stage disease, who are expected to have a better prognosis, often experience recurrence. Thus, it is important to identify the risk factors for early recurrence and to develop an adequate treatment plan.

AIM

To evaluate the predictive factors associated with the early recurrence of early-stage PDAC.

METHODS

This study enrolled 407 patients with stage I PDAC undergoing upfront surgical resection between January 2000 and April 2016. Early recurrence was defined as a diagnosis of recurrence within 6 mo of surgery. The optimal cutoff values were determined by receiver operating characteristic (ROC) analyses. Univariate and multivariate analyses were performed to identify the risk factors for early recurrence.

RESULTS

Of the 407 patients, 98 patients (24.1%) experienced early disease recurrence: 26 (26.5%) local and 72 (73.5%) distant sites. In total, 253 (62.2%) patients received adjuvant chemotherapy. On ROC curve analysis, the optimal cutoff values for early recurrence were 70 U/mL and 2.85 cm for carbohydrate antigen 19-9 (CA 19-9) levels and tumor size, respectively. Of the 181 patients with CA 19-9 level > 70 U/mL, 59 (32.6%) had early recurrence, compared to 39 (17.4%) of 226 patients with CA 19-9 level ≤ 70 U/mL (P < 0.001). Multivariate analysis revealed that CA 19-9 level > 70 U/mL (P = 0.006), tumor size > 2.85 cm (P = 0.004), poor differentiation (P = 0.008), and non-adjuvant chemotherapy (P = 0.025) were significant risk factors for early recurrence in early-stage PDAC.

CONCLUSION

Elevated CA 19-9 level (cutoff value > 70 U/mL) can be a reliable predictive factor for early recurrence in early-stage PDAC. As adjuvant chemotherapy can prevent early recurrence, it should be recommended for patients susceptible to early recurrence.

Imaging Strategy that Achieves Ultrahigh Contrast by Utilizing Differential Esterase Activity in Organs: Application in Early Detection of Pancreatic Cancer

Most nanoparticles show much higher uptake in mononuclear phagocyte system (MPS) organs than in tumors, which has been a long-lasting dilemma in nanomedicine. Here, we report an imaging strategy that selectively decreases MPS organ uptakes by utilizing the differential esterase activity in tumors and other organs. When an esterase-labile radiotracer loaded liposome was injected into the body, radioactivity was rapidly excreted from the liver and spleen after breakage of the ester bond by esterase. However, the lipophilic radiotracer delivered to the tumor remained in the tumor with minimal bond cleavage. The underlying mechanism was fully characterized in vitro and in vivo in colon tumor models. As a proof of concept, the liposomal radiotracer was further optimized for the early detection of pancreatic cancer. The folate-coated liposomal radiotracer showed highly selective tumor uptake. At 4 h postinjection, a pancreatic tumor a few millimeters in size was unambiguously visualized in orthotopic tumor models by PET imaging. At 24 h, an exceptionally high tumor-to-background ratio was achieved, enabling the visualization of tumors alone with minimal background noise. More than 9% of the total radioactivity was found in the tumor. Utilizing our imaging strategy, various tumor imaging agents can be developed for sensitive detection with ultrahigh contrast.

Analysis of KRAS Mutation Subtype in Tissue DNA and Cell-Free DNA Using Droplet Digital PCR and the Function of Cell-Free DNA as a Recurrence Predictive Marker in Pancreatic Cancer

KRAS mutation is a major regulator in the tumor progression of pancreatic cancer. Here, we compared the frequency and mutation burden of KRAS mutation subtypes with paired tumor tissue and blood in patients and examined their clinical significance. DNA from tumor tissues and cell-free DNA (cfDNA) from preoperative blood were obtained from 70 patients with pancreatic cancer. Subtypes and mutation burdens of KRAS G12D and G12V mutations were evaluated using droplet digital PCR. Comparing the presence of mutations in tissue, accumulative and simultaneous mutations of G12D or G12V were identified of 67 (95.7%), and 48 patients (68.6%). Conversely, in blood, they were only identified in 18 (25.7%) and four (5.7%) patients; respectively. Next, comparing the mutation burden in tissue, the mutation burden varied from less than 0.1 to more than five, whereas that of cfDNA in blood was mostly between one and five, as cases with a mutation burden lower than 0.1 and higher than five were rare. Finally, the presence of the G12V mutation alone in cfDNA and the combination of the G12V mutation with elevated CA 19-9 levels were associated with poor recurrence-free survival. These fundamental data on the KRAS mutation subtypes and their clinical significance could support their potential as predictive markers for postoperative recurrence.

Clinical Outcome of RAMPS for Left-Sided Pancreatic Ductal Adenocarcinoma: A Comparison of Anterior RAMPS versus Posterior RAMPS for Patients without Periadrenal Infiltration

Radical antegrade modular pancreatosplenectomy (RAMPS) is considered an effective procedure for left-sided pancreatic ductal adenocarcinoma (PDAC). However, whether there are differences in perioperative outcomes, pathologies, or survival outcomes between anterior RAMPS (aRAMPS) and posterior RAMPS (pRAMPS) has not been reported previously. We retrospectively reviewed and compared the demographic, perioperative, histopathologic, and survival data of patients who underwent aRAMPS or pRAMPS for PDAC. We also compared these two groups among patients without periadrenal infiltration or adrenal invasion. A total of 112 aRAMPS patients and 224 pRAMPS patients were evaluated. Periadrenal infiltration, neoadjuvant treatment, and concurrent vessel resection were more prevalent in the pRAMPS group. After excluding patients with periadrenal infiltration, 106 aRAMPS patients were compared with 157 pRAMPS patients. There were no significant differences between the aRAMPS and pRAMPS groups in the pathologic tumor size, resection margin, proportion of tangential margin in the R1 resection, and number of harvested lymph nodes. The median overall survival and disease-free survival also did not differ significantly between the two groups. We cautiously suggest that pRAMPS will not necessarily provide more beneficial histopathologic outcomes and survival rates for left-sided PDAC cases without periadrenal infiltration. If periadrenal infiltration is not suspected, aRAMPS alone should be sufficiently effective.

Predictive Performance of Current Nodal Staging Systems in Various Categories of Pancreatic Cancer

BACKGROUND

Nodal staging systems (NSS) for pancreatic ductal adenocarcinoma (PDAC) classify patients on the basis of number of metastatic lymph nodes (MLN), metastatic/retrieved lymph node ratio (LNR), and log odds of positive LN (LODDS). The relative prognostic performance of these NSS, however, remains unclear.

PATIENTS AND METHODS

We identified 2584 patients who underwent surgery for PDAC between 2010 and 2019. Subgroups of each staging system were classified using K-adaptive partitioning method and assessed by comparing time-dependent areas under the curve (AUC) 5 years after surgery.

RESULTS

Patients were subgrouped by MLN (0, 1-3, ≥ 4), LNR (0, 0-0.23, > 0.23), and LODDS (< - 3.5, - 3.5 to - 0.970, > - 0.97). All three NSS were independent prognostic factors for overall survival (OS) and recurrence-free survival (RFS). The AUCs for OS were comparable for the MLN (0.622), LNR (0.609), and LODDS (0.596) systems. Subgroup evaluation based on 12 retrieved lymph nodes (RLN), R1 resection, and extent of resection showed that the AUCs of the MLN and LNR NSS were comparable for OS and RFS regardless of the number of RLNs, R1 resection, and extent of resection. By contrast, the AUCs of the LODDS NSS were lower.

CONCLUSION

The NSS based on the number of MLN is the best prognostic indicator, with prognostic performance comparable to the other NSS and greater convenience for practical use. This NSS was applicable regardless of the numbers of RLN, R1 resection, and extent of resection.

Metabolic activity by FDG-PET/CT after neoadjuvant chemotherapy in borderline resectable and locally advanced pancreatic cancer and association with survival

BACKGROUND

The optimal prognostic markers for neoadjuvant chemotherapy in patients with borderline resectable or locally advanced pancreatic cancer are not yet established.

METHOD

Patients who received neoadjuvant chemotherapy prior to surgery and underwent FDG-PET/CT between July 2012 and December 2017 were included. Metabolic parameters including standardised uptake value (SUV), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) on PET/CT, and response evaluations using PERCIST criteria, were investigated for its impact on survival and recurrence. Cox proportional hazards model was performed. Differences in risk were expressed as hazard ratio [HR] with 95% confidence interval [c.i.].

RESULTS

The patients with borderline resectable (N = 106) or locally advanced pancreatic cancer (N = 82) were identified. The median survival was 33.6 months. Decreased metabolic parameters of PET/CT after neoadjuvant chemotherapy were associated with positive impacts on survival and recurrence such as SUVmax (HR 1.16, 95% c.i. 1.01 to 1.32, P = 0.025), SUVpeak (HR 1.26, 95% c.i. 1.05 to 1.51, P = 0.011), and MTV (HR 1.15, 95% c.i. 1.04 to 1.26, P = 0.005). Large delta values were related to a positive impact on recurrence such as SUVmax (HR 1.21, 95% c.i. 1.06 to 1.38, P = 0.005). Post-neoadjuvant chemotherapy SUVmax ≥3 (HR 3.46, 95% c.i. 1.21 to 9.91; P = 0.036) was an independent prognostic factor for negative impact on survival. Patients with post-neoadjuvant chemotherapy SUVmax <3 showed more chemotherapy cycles (8.7 versus 6.2, P = 0.001), more frequent complete metabolic response (25 vs 2.2%, P = 0.002), smaller tumour size (2.1 vs 3.1 cm, P = 0.002), and less frequent lymphovascular invasion (23.7 vs 51.1%, P = 0.020) than patients with SUVmax ≥3.

CONCLUSION

Reduction in metabolic tumour parameters of FDG- PET/CT after neoadjuvant chemotherapy indicates improved overall survival and recurrence-free survival.

Clinical Outcomes Between a Minimally Invasive and Open Extended Cholecystectomy for T2 Gallbladder Cancer: A Propensity Score Matching Analysis

Background: Although a minimally invasive extended cholecystectomy (MIEC) for T2 gallbladder cancer (T2 GBC) has been performed in many experienced centers, no oncologic comparison with open extended cholecystectomy (OEC) has yet been reported. Methods: T2 GBC patients who underwent MIEC (n = 60) or OEC (n = 135) were enrolled. We used propensity score matching (PSM) using pre- and intraoperative variables. Short- and long-term outcomes were then compared before and after PSM. Results: Before PSM, OEC patients more frequently showed completion of surgery after a simple cholecystectomy (standardized mean difference [SMD] = -0.551), and lymph node enlargement on preoperative computed tomography (SMD = -0.471). PSM was used to select 56 patients from each of the 2 patient groups. MIEC patients showed comparable complication rate (7.1% versus 12.5%, P = .365) and shorter hospital stay (5.7 days versus 9.8 days, P < .001). The median follow-up period was 26.2 months, and 5-year overall survival (OS) rate (96.8% versus 91.1%, P = .464) and 5-year recurrence free survival (RFS) (54.7% versus 44.4%, P = .580) outcomes were still comparable between MIEC and OEC groups. Conclusion: MIEC have advantages such as early recovery and comparable short-term outcomes compared with OEC. MIEC showed comparable OS and RFS outcomes compared with OEC. MIEC is a safe option without oncological compromise for T2 GBC.

The clinicopathologic and operative characteristics of patients with small nonfunctioning pancreatic neuroendocrine tumors

BACKGROUND

Incidentally detected, small nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs) are increasingly diagnosed on imaging modalities. This retrospective investigation evaluated the clinicopathologic characteristics and perioperative and oncologic outcomes in patients with small NF-PNETs undergoing curative resection.

METHODS

The medical records of 444 patients who underwent pancreatic resection for NF-PNETs at a single, large-volume institution between January 2000 and December 2018 were retrospectively reviewed. Patients were divided into those with small (≤2 cm) and large (>2 cm) tumors based on the largest tumor diameter on preoperative computed tomography (CT). Outcomes were also evaluated in subgroups of patients with small NF-PNET who did and did not undergo lymphadenectomy.

RESULTS

Of the 444 patients with NF-PNETs, 195 (43.9%) had small (≤2 cm) and 249 (56.1%) had large (>2 cm) NF-PNETs. The rate of parenchyma-preserving surgery (14.4% vs. 7.2%, p = 0.014) and the ratio of spleen preservation for left-sided pancreatectomy (65.6% vs. 38.3%, p < 0.001) were higher in the small NF-PNET group. Size on CT >2 cm (p < 0.001, hazard ratio [HR]: 5.836, 95% confidence interval [CI]: 2.474-13.769), presence of perineural invasion (p < 0.001, HR: 3.025, 95% CI: 1.640-5.577), World Health Organization (WHO) Grade 2 (p = 0.007, HR: 2.861, 95% CI: 1.325-6.176), and WHO Grade 3 (p < 0.001, HR: 11.537, 95% CI: 5.282-25.199) were independent predictors of disease-free survival (DFS). DFS did not differ significantly in patients with small NF-PNETs who did and did not undergo lymphadenectomy (p = 0.886).

CONCLUSIONS

Assessment of long-term oncologic outcomes suggests that surgical resection may cure small NF-PNETs. Minimally invasive surgery and organ-preserving surgery are acceptable treatment options for select patients with small NF-PNETs. The effect on survival outcomes of lymph node dissection for small NF-PNETs remains unclear.

Tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding neuropeptides via Lgr3/8 in the brain

In patients with advanced-stage cancer, cancer-associated anorexia affects treatment success and patient survival. However, the underlying mechanism is poorly understood. Here, we show that Dilp8, a Drosophila homologue of mammalian insulin-like 3 peptide (INSL3), is secreted from tumour tissues and induces anorexia through the Lgr3 receptor in the brain. Activated Dilp8-Lgr3 signalling upregulated anorexigenic nucleobinding 1 (NUCB1) and downregulated orexigenic short neuropeptide F (sNPF) and NPF expression in the brain. In the cancer condition, the protein expression of Lgr3 and NUCB1 was significantly upregulated in neurons expressing sNPF and NPF. INSL3 levels were increased in tumour-implanted mice and INSL3-treated mouse hypothalamic cells showed Nucb2 upregulation and Npy downregulation. Food consumption was significantly reduced in intracerebrospinal INSL3-injected mice. In patients with pancreatic cancer, higher serum INSL3 levels increased anorexia. These results indicate that tumour-derived Dilp8/INSL3 induces cancer anorexia by regulating feeding hormones through the Lgr3/Lgr8 receptor in Drosophila and mammals.

Circulating tumour cells as an indicator of early and systemic recurrence after surgical resection in pancreatic ductal adenocarcinoma

Early recurrence in pancreatic ductal adenocarcinoma (PDAC) is a decisive factor in determining a patient's prognosis. We determined in our current study whether circulating tumour cells (CTCs) exist in the blood of PDAC patients and can be used as a predictor of recurrence patterns (i.e. time and site) after surgical resection. Between December 2017 and November 2018, the mononuclear cell layer was obtained from the peripheral blood of 36 patients diagnosed with PDAC. CTCs were then isolated using the CD-PRIME™ platform and detected via immunostaining. The patient records were analyzed to correlate these data with survival and recurrence patterns. Twelve patients were CTC-positive (33.3%) and showed a significantly frequent rate of systemic recurrence (distant metastases and peritoneal dissemination) (p = 0.025). On multi-variable logistic regression analysis, CTC positivity was an independent risk factor for early recurrence (p = 0.027) and for systemic recurrence (p = 0.033). In summary, the presence or absence of CTC in the blood of the patients with PDAC could help predict the recurrence pattern after surgery. PDAC patients with CTC positivity at tumour diagnosis should therefore undergo a comprehensive strategy for systemic therapy and active monitoring to detect possible early recurrence.

A comparison of minimally invasive vs open distal pancreatectomy for resectable pancreatic ductal adenocarcinoma: Propensity score matching analysis

BACKGROUND

Owing to concerns regarding adequate oncological outcomes and perioperative complications, minimally invasive distal pancreatectomy (MIDP) for pancreatic ductal adenocarcinoma (PDAC) has limited generalizability. The aim of this study was to assess the perioperative and oncologic outcomes of MIDP compared with open distal pancreatectomy (ODP) for resectable PDAC after propensity score matching (PSM).

METHODS

The patients who underwent MIDP and ODP for PDAC between January 2010 and December 2017 were retrospectively reviewed. Demographics, perioperative outcomes, pathological outcomes, and overall and disease-free survival data were collected to compare MIDP and ODP. After PSM, perioperative and oncologic outcomes were analyzed.

RESULTS

A total of 156 MIDP patients were compared with 156 ODP patients for resectable PDAC after PSM. Tumor size, TNM stage, differentiation, harvested lymph nodes, and positive lymph nodes were not different except for R1 resection and lymphovascular invasion between the MIDP and ODP groups. Operation times, overall complications, POPF, and adjuvant treatment were also not different between the two groups. The MIDP group had shorter hospital stays (10.0 vs 13.4 days, P < 0.001) and shorter interval times from surgery to adjuvant treatment (37.6 days vs 46.0 days, P = 0.002) than the ODP group. The MIDP group had better overall survival (34.9 vs 24.5 months, P = 0.012) and disease-free survival (16.2 vs 10.3 months, P = 0.001).

CONCLUSION

Minimally invasive distal pancreatectomy has advantages with respect to postoperative hospital stay, interval between surgery, and adjuvant treatment. MIDP is associated with the possibility of improved survival rate for resectable PDAC.

A biocomposite-based rapid sampling assay for circulating cell-free DNA in liquid biopsy samples from human cancers

Cell-free nucleic acids (cfNAs) in liquid biopsy samples are emerging as important biomarkers for cancer diagnosis and monitoring, and for predicting treatment outcomes. Many cfNA isolation methods have been developed recently. However, most of these techniques are time-consuming, complex, require large equipment, and yield low-purity cfNAs because the genetic background of normal cells is amplified during cell lysis, which limits their clinical application. Here, we report a rapid and simple cfNA sampling platform that can overcome the limitations of conventional methods. We synthesised a biocomposite by combining amine-modified diatomaceous earth (DE) and cucurbituril (CB). The biocomposite platform showed high capture efficiency (86.78-90.26%) with genomic DNA and amplified DNA products (777, 525 and 150 bp). The biocomposite platform allowed the isolation of high purity and quantity cfDNAs from the plasma of 13 cancer patients (three colorectal cancer and ten pancreatic cancer samples) without requiring a lysis step or special equipment. The biocomposite platform may be useful to isolate cfNAs for the diagnosis and treatment of cancers in clinical applications.

Predictive Factors Associated with Complications after Laparoscopic Distal Pancreatectomy

Although laparoscopic distal pancreatectomy (LDP) has become more popular, the postoperative complication rate remains high. We sought to identify the risk factors for post-LDP complications. We examined 1227 patients who underwent LDP between March 2005 and December 2015 at a single large-volume center. We used logistic regression for the analysis. The overall (13.2%) and major (3.3%) complication rates were determined. Postoperative pancreatic fistula was the most frequent complication, and 58 patients (4.7%) had clinically significant (grade B) pancreatic fistulas. No 90-day mortality was recorded. Long operative time (≥200 min), large estimated blood loss (≥320 mL), LDP performed by an inexperienced surgeon (<50 cases), and concomitant splenectomy were identified as risk factors for overall complications using a logistic regression model. For major complications, male sex (p = 0.020), long operative time (p = 0.005), and LDP performed by an inexperienced surgeon (p = 0.026) were significant predictive factors. Using logistic regression analysis, surgery-related factors, including long operative time and LDP performed by an inexperienced surgeon, were correlated with overall and major complications of LDP. As LDP is a technically challenging procedure, surgery-related variables emerged as the main risk factors for postoperative complications. Appropriate patient selection and sufficient surgeon experience may be essential to reduce the complications of LDP.

Diversity in the Extracellular Vesicle-Derived Microbiome of Tissues According to Tumor Progression in Pancreatic Cancer

This study was conducted to identify the composition and diversity of the microbiome in tissues of pancreatic cancer and to determine its role. First, extracellular vesicles (EVs) were obtained from the paired tumor and normal tissues, and 16s rRNA gene sequencing was performed. We identified the microbiomes, compared the diversity between groups, and found that Tepidimonas was more abundant in tumors. Second, larger tumors resulted in lower levels of Leuconostoc and Sutterella, and increased lymph node metastasis resulted in higher levels of Comamonas and Turicibacter in tumor tissues. Moreover, in the case of tumor recurrence, the levels of Streptococcus and Akkermansia were decreased in tumor tissues. Finally, with the supernatant of Tepidimonasfonticaldi, proliferation and migration of cells increased, and epithelial-mesenchymal transition and the Tricarboxylic Acid (TCA) cycle-related metabolites were enhanced. The composition and diversity of EV-derived microbiomes are important for providing novel insights into theragnostic approaches in pancreatic cancer.

The identification of candidate effective combination regimens for pancreatic cancer using the histoculture drug response assay

The prognosis for patients with pancreatic cancer is extremely poor, as they are resistant to first line chemotherapy. The long-term goal of this study was to identify effective combination chemotherapy for pancreatic cancer using pancreatic cancer surgical specimens in the histoculture drug response assay (HDRA) based on three-dimensional culture of tumour fragments, which maintains nature tumour histology in vitro. From 2015 to 2017, the HDRA was performed with tumour specimens from 52 pancreatic cancer patients from Asan Medical Hospital. First, combination drug regimens showed higher drug efficacy and less patient variation than single drugs. Initially, 5-Fluorouracil(5-FU)/Belotecan/Oxaliplatinum and Tegafur/Gimeracil (TS-1)/Oxaliplatinum/Irinotecan were found to be effective. Second, we were able to correlate the efficacy of some drugs with tumour stage. Third, when designing new combination regimens containing 5-FU or gemcitabine, we could identify more effective drug combinations. This is the first study to demonstrate usefulness of the HDRA for pancreatic cancer. Using this technique, we could identify novel candidate combination drug regimens that should be effective in treating pancreatic cancer.

Rationally designed redirection of natural killer cells anchoring a cytotoxic ligand for pancreatic cancer treatment

The emergence of T-cell engineering with chimeric antigen receptors (CARs) has led to attractive therapeutics; however, autologous CAR-T cells are associated with poor clinical outcomes in solid tumors because of low safety and efficacy. Therefore, the aim of our study was to develop a CAR therapy with enhanced cytotoxicity against solid cancer using allogeneic NK cells. In this study, we engineered "off-the-shelf" NK cells to redirect them towards pancreatic ductal adenocarcinoma (PDAC) by improving their target-specific cytotoxic potential. By integrated bioinformatic and clinicopathological analyses, folate receptor alpha (FRα) and death receptor 4 (DR4) were significantly highly expressed in patient-derived tumor cells. The combined expression of FRα and DR4/5 was associated with inferior clinical outcomes, therefore indicating their use as potential targets for biomolecular treatment. Thus, FRα and DR4 expression pattern can be a strong prognostic factor as promising therapeutic targets for the treatment of PDAC. For effective PDAC treatment, allogeneic CAR-NK cells were reprogrammed to carry an apoptosis-inducing ligand and to redirect them towards FRα and initiate DR4/5-mediated cancer-selective cell death in FRα- and DR4/5-positive tumors. As a result, the redirected cytotoxic ligand-loaded NK cells led to a significantly enhanced tumor-selective apoptosis. Accordingly, use of allogeneic CAR-NK cells that respond to FRα and DR4/5 double-positive cancers might improve clinical outcomes based on personal genome profiles. Thus, therapeutic modalities based on allogeneic NK cells can potentially be used to treat large numbers of patients with optimally selective cytotoxicity.

A Comparative Study of Laparoscopic versus Open Pancreaticoduodenectomy for Ampulla of Vater Carcinoma

Several studies have compared laparoscopic pancreaticoduodenectomy (LPD) and open pancreaticoduodenectomy (OPD) in patients with periampullary carcinoma; however, only a few studies have made such a comparison on patients with ampulla of Vater cancer (AVC). We compared the perioperative and oncologic outcomes between LPD and OPD in patients with AVC using propensity-score-matched analysis. A total of 359 patients underwent PD due to AVC during the study period (76 LPD, 283 OPD). After propensity score matching, the LPD group showed significantly longer operation time than did the OPD group (400.2 vs. 344.6 min, p < 0.001). Nevertheless, the LPD group had fewer painkiller administrations (8.3 vs. 11.1, p < 0.049), fewer Grade II or more severe postoperative complications (15.9% vs. 34.8%, p = 0.012), and shorter postoperative hospital stays (13.7 vs. 17.3 days, p = 0.048), compared with the OPD group. There was no significant difference in recurrence-free outcomes and overall survival between the two groups (p = 0.754 and 0.768, respectively). Compared with OPD, LPD for AVC had comparative oncologic outcomes with less pain, less postoperative morbidity, and shorter hospital stays. LPD may serve as a promising alternative to OPD in patients with AVC.

Abstract C63: The analysis of microbiota composition between tumor and normal tissues in pancreatic cancer and the comparison with the public data of NCBI

Purpose: The translocation of gut bacteria and its derivatives may be an essential factor contributing to the various diseases of the pancreas. However, microbial function on the development and progression of pancreatic cancer is not clear and the research is still lacking. The aim of this study is to analyze the composition of microbiota in pancreatic cancer tissue and to compare the result with the existing public data.

Methods: We obtained the cancer and normal tissues from patients who underwent pancreatic cancer surgery in Korea (IRB: 2018-0710), and total bacterial genomic DNA was purified from tissue. Through the gene sequencing of 16S rRNA (V3-V4 lesion), we analyzed the quantitative and qualitative composition of microbiome. Then we compared the microbiome composition with public data of NCBI (SRP132007).

Results: We successfully performed the gene sequencing of 16s rRNA from 12 tumor tissues and 6 normal tissues. Based on the results obtained from the tumor and normal tissues, we compared the composition from the phylum to the species levels. We confirmed that there were significant differences in the microbiome composition of the tumor and normal tissues and identified various strains of 20 or more species with a high specificity in tumor or normal tissues. In addition, through the comparison with SRP132007 data, we confirmed a distinct difference between the two groups.

Conclusions: We have analyzed the patterns and characteristics of tumor or normal specific microbiomes through pancreatic cancer tissues. There is a clear difference between the two groups with environmental differences, even in the microbiomes of patients with the same disease. We expect to further clarify the importance of microbiomes in pancreatic cancer and point to the development of new therapies through further studies.

Citation Format: Hwi Wan Choi, Jinju Kim, Eo Jin Kim, Eunsung Jun. The analysis of microbiota composition between tumor and normal tissues in pancreatic cancer and the comparison with the public data of NCBI [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C63.

Tannic acid attenuates the formation of cancer stem cells by inhibiting NF-κB-mediated phenotype transition of breast cancer cells

Cancer stem cells (CSCs) are innately resistant to standard therapies, which positions CSCs in the focus of anti-cancer research. In this study, we investigated the potential inhibitory effect of tannic acid (TA) on CSCs. Our data demonstrated that TA (10 μM), at the concentration not inhibiting the proliferation of normal mammary cells (MCF10A), inhibited the formation and growth of mammosphere in MCF7, T47D, MDA-MB-231 cells shown as a decrease in mammosphere formation efficiency (MFE), cell number, diameter of mammosphere, and ALDH1 activity. NF-κB pathway was activated in the mammosphere indicated by an up-regulation of p65, a degradation of IκBα, and an increased IL-6. The inhibition of NF-κB pathway via gene silencing of p65 (sip65), NF-κB inhibitor (PDTC), or IKK inhibitor (Bay11-7082) alleviated MFE. Other CSCs markers such as an increase in ALDH1 and CD44^high/CD24^low ratio were ameliorated by sip65. TA also alleviated TGFβ-induced EMT, increase in MFE, and NF-κB activation. In murine xenograft model, TA reduced tumor volume which was associated with a decrease in CD44^high/CD24^low expression and IKK phosphorylation. These results suggest that TA negatively regulates CSCs by inhibiting NF-κB activation and thereby prevents cancer cells from undergoing EMT and CSCs formation, and may thus be a promising therapy targeting CSCs.

Progressive Impairment of NK Cell Cytotoxic Degranulation Is Associated With TGF-β1 Deregulation and Disease Progression in Pancreatic Cancer

Natural killer (NK) cells are key effectors in cancer immunosurveillance and can be used as a prognostic biomarker in diverse cancers. Nonetheless, the role of NK cells in pancreatic cancer (PC) remains elusive, given conflicting data on their association with disease prognosis. In this study, using conventional K562 target cells and complementary engineered target cells providing defined and synergistic stimulation for NK cell activation, a correlation between impaired NK cell cytotoxic degranulation and PC progression was determined. Peripheral blood mononuclear cells (PBMCs) from 31 patients with newly diagnosed PC, 24 patients with non-malignant tumors, and 37 healthy controls were analyzed by flow cytometry. The frequency, phenotype, and effector functions of the NK cells were evaluated, and correlations between NK cell functions and disease stage and prognosis were analyzed. The results demonstrated that effector functions, but not frequency, of NK cells was progressively decreased on a per-cell basis during PC progression. Impaired cytotoxic degranulation, but not IFN-γ production, was associated with clinical features indicating disease progression, such as high serum CA19-9 and high-grade tumors. Significantly, this impairment correlated with cancer recurrence and mortality in a prospective analysis. Furthermore, the impaired cytotoxic degranulation was unrelated to NKG2D downregulation but was associated with increased circulating and tumor-associated TGF-β1 expression. Thus, NK cell cytotoxic activity was associated with PC progression and may be a favorable biomarker with predictive and prognostic value in PC.

Validation and Verification of Three-dimensional Systems in Laparoscopic Distal Pancreatectomy

AIM

The three-dimensional (3D) visualization system has been introduced for the technical improvement of laparoscopic surgery, but clinical evidence for its usefulness is lacking. This study aimed to evaluate the usefulness of a 3D system in laparoscopic surgery.

PATIENTS AND METHODS

Between 2015 and 2016, a randomized controlled trial was performed on 61 patients who underwent laparoscopic distal pancreatectomy. The primary outcome was the shortening of operative time. The hospital course, number of technical errors, and clinicians' subjective scores were compared as secondary outcome.

RESULTS

There were no significant differences in operative times, hospital course and technical errors. However, depth perception was significantly improved and physical demand was reduced in the 3D group. These advantages became clearer in the later period of the study, with longer operative times, and in spleen-preserving procedures.

CONCLUSION

Subjective scoring through 3D systems was significantly superior, which might lead to better surgical performance in difficult cases.

Enhanced insulin production and reprogramming efficiency of mesenchymal stem cells derived from porcine pancreas using suitable induction medium

BACKGROUND

Genetic reprogramming is a powerful method for altering cell properties and inducing differentiation. However, even if the same gene is reprogrammed, the results vary among cells. Therefore, a better possible strategy involves treating cells with factors that further stimulate differentiation while using stem cells with the same tissue origin. This study aimed to increase induction efficiency and insulin production in reprogrammed cells using a combination of factors that promote cell differentiation.

METHODS

Porcine pancreatic cells were cultured to obtain mesenchymal stem cells expressing pancreatic cell-specific markers through sequential passages. The characteristics of these cells were identified, and the M3 gene (Pdx1, Ngn3, MafA) was reprogrammed to induce differentiation into insulin-producing cells. Additionally, the differentiation efficiency of insulin-producing cells was compared by treating reprogrammed cells with a differentiation-promoting factor.

RESULTS

Mesenchymal stem cells isolated from porcine pancreatic tissues expressed exocrine cell markers, including amylase and cytokeratin 18, and most cells continuously expressed the beta cell transcription factors Ngn3 and NeuroD. Reprogramming of the M3 gene resulted in differentiation into insulin-producing cells. Moreover, significantly increased insulin and glucagon expressions were observed in the suitable induction medium, and the characteristic beta cell transcription factors Pdx1, Ngn3, and MafA were expressed at levels as high as those in pancreatic islet cells.

CONCLUSIONS

Differentiation into insulin-producing cells represents an alternative therapy for insufficient pancreatic islet cells when treating diabetes. Therefore, cells with the characteristics of the target cell should be used to improve differentiation efficiency by creating an environment that promotes reprogramming and differentiation.

Locally-applied 5-fluorouracil-loaded slow-release patch prevents pancreatic cancer growth in an orthotopic mouse model

To obtain improved efficacy against pancreatic cancer, we investigated the efficacy and safety of a locally-applied 5-fluorouracil (5-FU)-loaded polymeric patch on pancreatic tumors in an orthotopic nude-mouse model. The 5-FU-releasing polymeric patch was produced by 3D printing. After application of the patch, it released the drug slowly for 4 weeks, and suppressed BxPC-3 pancreas cancer growth. Luciferase imaging of BxPC3-Luc cells implanted in the pancreas was performed longitudinally. The drug patch delivered a 30.2 times higher level of 5-FU than an intra-peritoneal (i.p.) bolus injection on day-1. High 5-FU levels were accumulated within one week by the patch. Four groups were compared for efficacy of 5-FU. Drug-free patch as a negative control (Group I); 30% 5-FU-loaded patch (4.8 mg) (Group II); 5-FU i.p. once (4.8 mg) (Group III); 5-FU i.p. once a week (1.2 mg), three times (Group IV). The tumor growth rate was significantly faster in Group I than Group II, III, IV (p=0.047 at day-8, p=0.022 at day-12, p=0.002 at day-18 and p=0.034 at day-21). All mice in Group III died of drug toxicity within two weeks after injection. Group II showed more effective suppression of tumor growth than Group IV (p=0.018 at day-12 and p=0.017 at day-21). Histological analysis showed extensive apoptosis in the TUNEL assay and by Ki -67 staining. Western blotting confirmed strong expression of cleaved caspase-3 in Group II. No significant changes were found hematologically and histologically in the liver, kidney and spleen in Groups I, II, IV but were found in Group III.