Precursors to pancreatic cancer

Exploring patient experiences of surveillance for pancreatic cystic neoplasms: a qualitative study

BACKGROUND

Pancreatic cystic neoplasms (PCN) are considered premalignant conditions to pancreatic adenocarcinoma with varying degrees of cancerous potential. Management for individuals who do not require surgical treatment involves surveillance to assess for cancerous progression. Little is known about patients' experience and the impact of living with surveillance for these lesions.

AIMS

To explore the experiences of patients living with surveillance for PCNs.

METHODS

Semi-structured qualitative interviews were conducted with patients under surveillance for pancreatic cystic neoplasms in the UK. Age, gender, time from surveillance and surveillance method were used to purposively sample the patient group. Data were analysed using reflexive thematic analysis.

RESULTS

A PCN diagnosis is incidental and unexpected and for some, the beginning of a disruptive experience. How patients make sense of their PCN diagnosis is influenced by their existing understanding of pancreatic cancer, explanations from clinicians and the presence of coexisting health concerns. A lack of understanding of the diagnosis and its meaning for their future led to an overarching theme of uncertainty for the PCN population. Surveillance for PCN could be seen as a reminder of fears of PCN and cancer, or as an opportunity for reassurance.

CONCLUSIONS

Currently, individuals living with surveillance for PCNs experience uncertainty with a lack of support in making sense of a prognostically uncertain diagnosis with no immediate treatment. More research is needed to identify the needs of this population to make improvements to patient care and reduce negative experiences.

CYRI-B-mediated macropinocytosis drives metastasis via lysophosphatidic acid receptor uptake

Pancreatic ductal adenocarcinoma carries a dismal prognosis, with high rates of metastasis and few treatment options. Hyperactivation of KRAS in almost all tumours drives RAC1 activation, conferring enhanced migratory and proliferative capacity as well as macropinocytosis. Macropinocytosis is well understood as a nutrient scavenging mechanism, but little is known about its functions in trafficking of signalling receptors. We find that CYRI-B is highly expressed in pancreatic tumours in a mouse model of KRAS and p53-driven pancreatic cancer. Deletion of Cyrib (the gene encoding CYRI-B protein) accelerates tumourigenesis, leading to enhanced ERK and JNK-induced proliferation in precancerous lesions, indicating a potential role as a buffer of RAC1 hyperactivation in early stages. However, as disease progresses, loss of CYRI-B inhibits metastasis. CYRI-B depleted tumour cells show reduced chemotactic responses to lysophosphatidic acid, a major driver of tumour spread, due to impaired macropinocytic uptake of the lysophosphatidic acid receptor 1. Overall, we implicate CYRI-B as a mediator of growth and signalling in pancreatic cancer, providing new insights into pathways controlling metastasis.

Selective epigenetic alterations in RNF43 in pancreatic exocrine cells from high-fat-diet-induced obese mice; implications for pancreatic cancer

OBJECTIVE

Pancreatic cancer (PC) originates and progresses with genetic mutations in various oncogenes and suppressor genes, notably KRAS, CDKN2A, TP53, and SMAD4, prevalent across diverse PC cells. In addition to genetic mutations/deletions, persistent exposure to high-risk factors, including obesity, induces whole-genome scale epigenetic alterations contributing to malignancy. However, the impact of obesity on DNA methylation in the presymptomatic stage, particularly in genes prone to PC mutation, remains uncharacterized.

RESULTS

We analyzed the methylation levels of 197 loci in six genes (KRAS, CDKN2A, TP53, SMAD4, GNAS and RNF43) using Illumina Mouse Methylation BeadChip array (280 K) data from pancreatic exocrine cells obtained from high-fat-diet (HFD) induced obese mice. Results revealed no significant differences in methylation levels in loci between HFD- and normal-fat-diet (NFD)-fed mice, except for RNF43, a negative regulator of Wnt signaling, which showed hypermethylation in three loci. These findings indicate that, in mouse pancreatic exocrine cells, high-fat dietary obesity induced aberrant DNA methylation in RNF43 but not in other frequently mutated PC-related genes.

Cell of Origin of Pancreatic cancer: Novel Findings and Current Understanding

ABSTRACT

Pancreatic ductal adenocarcinoma (PDAC) stands as one of the most lethal diseases globally, boasting a grim 5-year survival prognosis. The origin cell and the molecular signaling pathways that drive PDAC progression are not entirely understood. This review comprehensively outlines the categorization of PDAC and its precursor lesions, expounds on the creation and utility of genetically engineered mouse models used in PDAC research, compiles a roster of commonly used markers for pancreatic progenitors, duct cells, and acinar cells, and briefly addresses the mechanisms involved in the progression of PDAC. We acknowledge the value of precise markers and suitable tracing tools to discern the cell of origin, as it can facilitate the creation of more effective models for PDAC exploration. These conclusions shed light on our existing understanding of foundational genetically engineered mouse models and focus on the origin and development of PDAC.

Digital spatial profiling of intraductal papillary mucinous neoplasms: Toward a molecular framework for risk stratification

The histopathologic heterogeneity of intraductal papillary mucinous neoplasms (IPMN) complicates the prediction of pancreatic ductal adenocarcinoma (PDAC) risk. Intratumoral regions of pancreaticobiliary (PB), intestinal (INT), and gastric foveolar (GF) epithelium may occur with either low-grade dysplasia (LGD) or high-grade dysplasia (HGD). We used digital spatial RNA profiling of dysplastic epithelium (83 regions) from surgically resected IPMN tissues (12 patients) to differentiate subtypes and predict genes associated with malignancy. The expression patterns of PB and GF lesions diverged from INT, suggesting that PB and GF arise from a common lineage. Transcriptional dysregulation within PB lesions mirrored that of PDAC, whereas INT and GF foci did not. Tumor necrosis factor/nuclear factor κB (TNF-NFκB) and cell cycle (cycling S and cycling G₂-M) programs occurred with relative prominence in PB and INT subtypes, respectively. Together, this study delineates markers of high-risk IPMN and insights into malignant progression.

Investigation of early neoplastic transformation and premalignant biology using genetically engineered organoid models

Organoid modeling is a powerful, robust and efficient technology faithfully preserving physiological and pathological characteristics of tissues of origin. Recently, substantial advances have been made in applying genetically engineered organoid models to study early tumorigenesis and premalignant biology. These efforts promise to identify novel avenues for early cancer detection, intervention and prevention. Here, we highlight significant advancements in the functional characterization of early genomic and epigenomic events during neoplastic evolution using organoid modeling, discuss the application of the lineage-tracing methodology in organoids to study cancer cells-of-origin, and review future opportunities for further development and improvement of organoid modeling of cancer precursors.

The molecular, immune features, and risk score construction of intraductal papillary mucinous neoplasm patients

Intraductal papillary mucinous neoplasm (IPMN) is a common pancreatic precancerous lesion, with increasing incidence in recent years. However, the mechanisms of IPMN progression into invasive cancer remain unclear. The mRNA expression data of IPMN/PAAD patients were extracted from the TCGA and GEO databases. First, based on GSE19650, we analyzed the molecular alterations, tumor stemness, immune landscape, and transcriptional regulation of IPMN progression. The results indicated that gene expression changed dramatically, specifically at the intraductal papillary-mucinous adenoma (IPMA) stage. Gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Kyoto Encyclopedia of Genes and Genomes (GSEA) pathway analyses showed that glycoprotein-related, cell cycle, and P53 pathways displayed the most significant changes during progression. With IPMN progression, tumor stemness increased continuously, and KRAS, ERBB3, RUNX1, and ELF3 are essential driver genes affecting tumor stemness. Motif analysis suggested that KLF4 may be a specific transcription factor that regulates gene expression in the IPMA stage, while MYB and MYBL1 control gene expression in the IPMC and invasive stages, respectively. Then, GSE19650 and GSE71729 transcriptome data were combined to perform the least absolute shrinkage and selection operator (LASSO) method and Cox regression analysis to develop an 11-gene prediction model (KCNK1, FHL2, LAMC2, CDCA7, GPX3, C7, VIP, HBA1, BTG2, MT1E, and LYVE1) to predict the prognosis of pancreatic cancer patients. The reliability of the model was validated in the GSE71729 and TCGA databases. Finally, 11 additional IPMN patients treated in our hospital were included, and the immune microenvironment changes during IPMN progression were analyzed by immunohistochemistry (IHC). IHC results suggest that Myeloid-derived suppressor cells (MDSCs) and macrophages may be key in the formation of immunosuppressive microenvironment of IPMN progression. Our study deepens our understanding of IPMN progression, especially the changes in the immune microenvironment. The findings of this work may contribute to the development of new therapeutic strategies for IPMN.

Exosomal glypican-1 is elevated in pancreatic cancer precursors and can signal genetic predisposition in the absence of endoscopic ultrasound abnormalities

BACKGROUND

Individuals within specific risk groups for pancreatic ductal adenocarcinoma (PDAC) [mucinous cystic lesions (MCLs), hereditary risk (HR), and new-late onset diabetes mellitus (NLOD)] represent an opportunity for early cancer detection. Endoscopic ultrasound (EUS) is a premium image modality for PDAC screening and precursor lesion characterization. While no specific biomarker is currently clinically available for this purpose, glypican-1 (GPC1) is overexpressed in the circulating exosomes (crExos) of patients with PDAC compared with healthy subjects or those harboring benign pancreatic diseases.

AIM

To evaluate the capacity of GPC1⁺ crExos to identify individuals at higher risk within these specific groups, all characterized by EUS.

METHODS

This cross-sectional study with a prospective unicentric cohort included 88 subjects: 40 patients with MCL, 20 individuals with HR, and 20 patients with NLOD. A control group (CG) was submitted to EUS for other reasons than pancreatic pathology, with normal pancreas and absence of hereditary risk factors (n = 8). The inclusion period was between October 2016 and January 2019, and the study was approved by the Ethics Committee of Centro Hospitalar Universitário de São João, Porto, Portugal. All patients provided written informed consent. EUS and blood tests for quantification of GPC1⁺ crExos by flow cytometry and carbohydrate antigen 19-9 (CA 19-9) levels by ELISA were performed in all subjects. EUS-guided tissue acquisition was done whenever necessary. For statistical analysis, SPSS^® 27.0 (IBM Corp., Armonk, NY, United States) version was used. All graphs were created using GraphPad Prism 7.00 (GraphPad Software, San Diego, CA, United States).

RESULTS

Half of MCLs harbored worrisome features (WF) or high-risk stigmata (HRS). Pancreatic abnormalities were detected by EUS in 10.0% and 35.0% in HR and NLOD individuals, respectively, all considered non-malignant and “harmless.” Median levels of GPC1⁺ crExos were statistically different: MCL [99.4%, interquartile range (IQR): 94.9%-99.8%], HR (82.0%, IQR: 28.9%-98.2%), NLOD (12.6%, IQR: 5.2%-63.4%), and CG (16.2%, IQR: 6.6%-20.1%) (P < 0.0001). Median levels of CA 19-9 were within the normal range in all groups (standard clinical cut-off of 37 U/mL). Within HR, individuals with a positive history of cancer had higher median levels of GPC1⁺ crExos (97.9%; IQR: 61.7%-99.5%), compared to those without (59.7%; IQR: 26.3%-96.4%), despite no statistical significance (P = 0.21). Pancreatic cysts with WF/HRS were statistically associated with higher median levels of GPC1⁺ crExos (99.6%; IQR: 97.6%-99.8%) compared to those without (96.5%; IQR: 81.3%-99.5%) (P = 0.011), presenting an area under the receiver operating characteristic curve value of 0.723 (sensitivity 75.0% and specificity 67.7%, using a cut-off of 98.5%; P = 0.012).

CONCLUSION

GPC1⁺ crExos may act as biomarker to support the diagnosis and stratification of PDAC precursor lesions, and in signaling individuals with genetic predisposition in the absence of EUS abnormalities.

Timeline of Development of Pancreatic Cancer and Implications for Successful Early Detection in High-Risk Individuals

BACKGROUND & AIMS

To successfully implement imaging-based pancreatic cancer (PC) surveillance, understanding the timeline and morphologic features of neoplastic progression is key. We aimed to investigate the progression to neoplasia from serial prediagnostic pancreatic imaging tests in high-risk individuals and identify factors associated with successful early detection.

METHODS

We retrospectively examined the development of pancreatic abnormalities in high-risk individuals who were diagnosed with PC or underwent pancreatic surgery, or both, in 16 international surveillance programs.

RESULTS

Of 2552 high-risk individuals under surveillance, 28 (1%) developed neoplastic progression to PC or high-grade dysplasia during a median follow-up of 29 months after baseline (interquartile range [IQR], 40 months). Of these, 13 of 28 (46%) presented with a new lesion (median size, 15 mm; range 7-57 mm), a median of 11 months (IQR, 8; range 3-17 months) after a prior examination, by which time 10 of 13 (77%) had progressed beyond the pancreas. The remaining 15 of 28 (54%) had neoplastic progression in a previously detected lesion (12 originally cystic, 2 indeterminate, 1 solid), and 11 (73%) had PC progressed beyond the pancreas. The 12 patients with cysts had been monitored for 21 months (IQR, 15 months) and had a median growth of 5 mm/y (IQR, 8 mm/y). Successful early detection (as high-grade dysplasia or PC confined to the pancreas) was associated with resection of cystic lesions (vs solid or indeterminate lesions (odds ratio, 5.388; 95% confidence interval, 1.525-19.029) and small lesions (odds ratio, 0.890/mm; 95% confidence interval 0.812-0.976/mm).

CONCLUSIONS

In nearly half of high-risk individuals developing high-grade dysplasia or PC, no prior lesions are detected by imaging, yet they present at an advanced stage. Progression can occur before the next scheduled annual examination. More sensitive diagnostic tools or a different management strategy for rapidly growing cysts are needed.

International external validation of a stratification tool to identify branch-duct intraductal papillary mucinous neoplasms at lowest risk of progression

Background

Identifying branch‐duct intraductal papillary mucinous neoplasms (BD‐IPMNs) at lowest risk of progression may allow for a reduced intensity of surveillance.

Objective

We aimed to externally validate the previously developed Dutch‐American Risk stratification Tool (DART‐1; https://rtools.mayo.edu/DART/), which identifies cysts at low risk of developing worrisome features (WFs) or high‐risk stigmata (HRS).

Methods

Three prospective cohorts of individuals under surveillance for BD‐IPMNs were combined, independent from the original development cohort. We assessed the performance (discrimination and calibration) of DART‐1, a multivariable Cox‐proportional logistic regression model with five predictors for the development of WFs or HRS.

Results

Of 832 individuals (mean age 77 years, SD 11.5) under surveillance for a median of 40 months (IQR 44), 163 (20%) developed WFs or HRS. DART‐1's discriminative ability (C‐statistic 0.68) was similar to that in the development cohort (0.64–0.72) and showed moderate calibration. DART‐1 adequately estimated the risk for patients in the middle risk quintile, and slightly underestimated it in the lowest quintiles. Their range of predicted versus observed 3‐year risk was 0%–0% versus 0%–3.7% for Q1; 0.3%–0.4% versus 3%–11% for Q2; and 2.6%–3% versus 2.4%–9.8% for Q3. The development of WFs or HRS was associated with pancreatic cancer (p < 0.001). Vice versa, in absence of WFs or HRS, the risk of malignancy was low (0.3%).

Conclusions

The performance of DART‐1 to predict the development of WFs or HRS in BD‐IPMN was validated in an external international cohort, with a discriminative ability equal as in the development cohort. Risk estimations were most accurate for patients with BD‐IPMNs in the middle risk quintile and slightly underestimated in the lowest quintiles.

Application of Proteomics in Pancreatic Ductal Adenocarcinoma Biomarker Investigations: A Review

Pancreatic ductal adenocarcinoma (PDAC), a highly aggressive malignancy with a poor prognosis is usually detected at the advanced stage of the disease. The only US Food and Drug Administration-approved biomarker that is available for PDAC, CA 19-9, is most useful in monitoring treatment response among PDAC patients rather than for early detection. Moreover, when CA 19-9 is solely used for diagnostic purposes, it has only a recorded sensitivity of 79% and specificity of 82% in symptomatic individuals. Therefore, there is an urgent need to identify reliable biomarkers for diagnosis (specifically for the early diagnosis), ascertain prognosis as well as to monitor treatment response and tumour recurrence of PDAC. In recent years, proteomic technologies are growing exponentially at an accelerated rate for a wide range of applications in cancer research. In this review, we discussed the current status of biomarker research for PDAC using various proteomic technologies. This review will explore the potential perspective for understanding and identifying the unique alterations in protein expressions that could prove beneficial in discovering new robust biomarkers to detect PDAC at an early stage, ascertain prognosis of patients with the disease in addition to monitoring treatment response and tumour recurrence of patients.

Deregulation of Transcription Factor Networks Driving Cell Plasticity and Metastasis in Pancreatic Cancer

Pancreatic cancer is a very aggressive disease with 5-year survival rates of less than 10%. The constantly increasing incidence and stagnant patient outcomes despite changes in treatment regimens emphasize the requirement of a better understanding of the disease mechanisms. Challenges in treating pancreatic cancer include diagnosis at already progressed disease states due to the lack of early detection methods, rapid acquisition of therapy resistance, and high metastatic competence. Pancreatic ductal adenocarcinoma, the most prevalent type of pancreatic cancer, frequently shows dominant-active mutations in KRAS and TP53 as well as inactivation of genes involved in differentiation and cell-cycle regulation (e.g. SMAD4 and CDKN2A). Besides somatic mutations, deregulated transcription factor activities strongly contribute to disease progression. Specifically, transcriptional regulatory networks essential for proper lineage specification and differentiation during pancreas development are reactivated or become deregulated in the context of cancer and exacerbate progression towards an aggressive phenotype. This review summarizes the recent literature on transcription factor networks and epigenetic gene regulation that play a crucial role during tumorigenesis.

Pancreatic Cancer and Platelets Crosstalk: A Potential Biomarker and Target

Platelets have been recognized as key players in hemostasis, thrombosis, and cancer. Preclinical and clinical researches evidenced that tumorigenesis and metastasis can be promoted by platelets through a wide variety of crosstalk between cancer cells and platelets. Pancreatic cancer is a devastating disease with high morbidity and mortality worldwide. Although the relationship between pancreatic cancer and platelets in clinical diagnosis is described, the interplay between pancreatic cancer and platelets, the underlying pathological mechanism and pathways remain a matter of intensive study. This review summaries recent researches in connections between platelets and pancreatic cancer. The existing data showed different underlying mechanisms were involved in their complex crosstalk. Typically, pancreatic tumor accelerates platelet aggregation which forms thrombosis. Furthermore, extracellular vesicles released by platelets promote communication in a neoplastic microenvironment and illustrate how these interactions drive disease progression. We also discuss the advantages of novel model organoids in pancreatic cancer research. A more in-depth understanding of tumor and platelets crosstalk which is based on organoids and translational therapies may provide potential diagnostic and therapeutic strategies for pancreatic cancer progression.

Reliable Detection of Somatic Mutations for Pancreatic Cancer in Endoscopic Ultrasonography-Guided Fine Needle Aspirates with Next-Generation Sequencing: Implications from a Prospective Cohort Study

BACKGROUND OR PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is commonly diagnosed by endoscopic ultrasound-guided fine needle aspiration (EUS-FNA). However, the diagnostic adequacy of EUS-FNA is often limited by low cellularity leading to inconclusive results. We aimed to investigate the feasibility and added utility of targeted next-generation sequencing (NGS) on PDAC EUS-FNAs.

METHODS

EUS-FNAs were prospectively performed on 59 patients with suspected PDAC (2014-2017) at a high-volume center. FNAs were analyzed for the presence of somatic mutations using NGS to supplement cytopathologic evaluations and were compared to surgical specimens and circulating tumor DNA (ctDNA).

RESULTS

Fifty-nine patients with suspected PDAC were evaluated, and 52 were diagnosed with PDAC on EUS-FNA. Four of the remaining seven patients had inconclusive EUS-FNAs and were ultimately diagnosed with PDAC after surgical resection. Of these 56 cases of PDAC, 48 (85.7%) and 18 (32.1%) harbored a KRAS and/or TP53 mutation on FNA NGS, respectively. Particularly, in the four inconclusive FNA PDAC diagnoses (false negatives), half harbored KRAS mutations on FNA. No KRAS/TP53 mutation was found in remaining three non-PDAC cases. All EUS-FNA detected KRAS mutations were detected in 16 patients that underwent primary tumor NGS (100% concordance), while 75% KRAS concordance was found between FNA and ctDNA NGS.

CONCLUSION

Targeted NGS can reliably detect KRAS mutations from EUS-FNA samples and exhibits high KRAS mutational concordance with primary tumor and ctDNA. This suggests targeted NGS of EUS-FNA samples may enable preoperative ctDNA prognostication using digital droplet PCR and supplement diagnoses in patients with inconclusive EUS-FNA.

Intraductal Papillary Mucinous Neoplasms of the Pancreas: A Review of Their Genetic Characteristics and Mouse Models

Simple Summary

Pancreatic cancer is one of the deadliest cancers with the lowest survival rate. Little progress has been achieved in prolonging the survival for patients with pancreatic adenocarcinoma. Hence, special attention should be paid to pre-cancerous lesions, for instance, an intraductal papillary mucinous neoplasm (IPMN). Here, we reviewed its genetic characteristics and the mouse models involving mutations in specific pathways, and updated our current perception of how this lesion develops into a precursor of invasive cancer.

Abstract

The intraductal papillary mucinous neoplasm (IPMN) is attracting research attention because of its increasing incidence and proven potential to progress into invasive pancreatic ductal adenocarcinoma (PDAC). In this review, we summarized the key signaling pathways or protein complexes (GPCR, TGF, SWI/SNF, WNT, and PI3K) that appear to be involved in IPMN pathogenesis. In addition, we collected information regarding all the genetic mouse models that mimic the human IPMN phenotype with specific immunohistochemistry techniques. The mouse models enable us to gain insight into the complex mechanism of the origin of IPMN, revealing that it can be developed from both acinar cells and duct cells according to different models. Furthermore, recent genomic studies describe the potential mechanism by which heterogeneous IPMN gives rise to malignant carcinoma through sequential, branch-off, or de novo approaches. The most intractable problem is that the risk of malignancy persists to some extent even if the primary IPMN is excised with a perfect margin, calling for the re-evaluation and improvement of diagnostic, pre-emptive, and therapeutic measures.

PGC1α-Mediated Metabolic Reprogramming Drives the Stemness of Pancreatic Precursor Lesions

PURPOSE

Metabolic reprogramming and cancer stem cells drive the aggressiveness of pancreatic ductal adenocarcinoma (PDAC). However, the metabolic and stemness programs of pancreatic precursor lesions (PPL), considered early PDAC development events, have not been thoroughly explored.

EXPERIMENTAL DESIGN

Meta-analyses using gene expression profile data from NCBI Gene Expression Omnibus and IHC on tissue microarrays (TMA) were performed. The following animal and cellular models were used: cerulean-induced Kras^G12D; Pdx1 Cre (KC) acinar-to-ductal metaplasia (ADM) mice, Kras^G12D; Smad4^Loss; Pdx-1 Cre (KC^Smad4-) intraductal papillary mucinous neoplasm (IPMN) mice, LGKC1 cell line derived from the doxycycline-inducible Gnas IPMN model, and human IPMN organoids. Flow cytometry, Seahorse extracellular flux analyzer, qRT-PCR, and sphere assay were used to analyze metabolic and stemness features. SR18292 was used to inhibit PGC1α, and short hairpin RNA was used to knockdown (KD) PGC1α.

RESULTS

The meta-analysis revealed a significant upregulation of specific stemness genes in ADM-mediated pancreatic intraepithelial neoplasms (PanIN) and IPMN. Meta- and TMA analyses followed by in vitro and in vivo validation revealed that ADM/PanIN exhibit increased PGC1α and oxidative phosphorylation (OXPhos) but reduced CPT1A. IPMN showed elevated PGC1α, fatty acid β-oxidation (FAO) gene expression, and FAO-OXPhos. PGC1α was co-overexpressed with its coactivator NRF1 in ADM/PanINs and with PPARγ in IPMN. PGC1α KD or SR18292 inhibited the specific metabolic and stemness features of PPLs and repressed IPMN organoid growth.

CONCLUSIONS

ADM/PanINs and IPMNs show specific stemness signatures with unique metabolisms. Inhibition of PGC1α using SR18292 diminishes the specific stemness by targeting FAO-independent and FAO-dependent OXPhos of ADM/PanINs and IPMNs, respectively.

Large-duct pattern invasive adenocarcinoma of the pancreas–a variant mimicking pancreatic cystic neoplasms: A minireview

Pancreatic cancer currently has no subtypes that inform clinical decisions; hence, there exists an opportunity to rearrange the morphological and molecular taxonomy that guides a better understanding of tumor characteristics. Nonetheless, accumulating studies to date have revealed the large-duct type variant, a unique subtype of pancreatic ductal adenocarcinoma (PDA) with cystic features. This subtype often radiographically mimics intraductal papillary mucinous neoplasms (IPMNs) and involves multiple small cysts occasionally associated with solid masses. The “bunch-of-grapes” sign, an imaging characteristic of IPMNs, is absent in large-duct PDA. Large-duct PDA defines the mucin profile, and genetic alterations are useful in distinguishing large-duct PDA from IPMNs. Histologically, neoplastic ducts measure over 0.5 mm, forming large ductal elements. Similar to classic PDAs, this subtype is frequently accompanied by perineural invasion and abundant desmoplastic reactions, and KRAS mutations in codon 12 are nearly ubiquitous. Despite such morphological similarities with IPMNs, the prognosis of large-duct PDA is equivalent to that of classic PDA. Differential diagnosis is therefore essential.

Clinicopathological impacts of DNA methylation alterations on pancreatic ductal adenocarcinoma: prediction of early recurrence based on genome-wide DNA methylation profiling

PURPOSE

The present study was conducted to clarify the clinicopathological impacts of DNA methylation alterations on pancreatic ductal adenocarcinoma (PDAC).

METHODS

Genome-wide DNA methylation screening was performed using the Infinium HumanMethylation450 BeadChip, and DNA methylation quantification was verified using pyrosequencing. We analyzed fresh-frozen tissues from an initial cohort (17 samples of normal control pancreatic tissue [C] from 17 patients without PDAC, and 34 samples of non-cancerous pancreatic tissue [N] and 82 samples of cancerous tissue [T] both obtained from 82 PDAC patients) and formalin-fixed paraffin-embedded T samples from 34 patients in a validation cohort.

RESULTS

The DNA methylation profiles of N samples tended to differ from those of C samples, and 91,907 probes showed significant differences in DNA methylation levels between C and T samples. Epigenetic clustering of T samples was significantly correlated with a larger tumor diameter and early recurrence (ER), defined as relapse within 6 months after surgery. Three marker CpG sites, applicable to formalin-fixed paraffin-embedded surgically resected materials regardless of their tumor cell content, were identified for prediction of ER. The sensitivity and specificity for detection of patients belonging to the ER group using a panel combining these three marker CpG sites, including a CpG site in the CDK14 gene, were 81.8% and 71.7% and 88.9% and 70.4% in the initial and validation cohorts, respectively.

CONCLUSION

These findings indicate that DNA methylation alterations may have a clinicopathological impact on PDAC. Application of our criteria will ultimately allow prediction of ER after surgery to improve the outcome of PDAC patients.

Commitment and oncogene-induced plasticity of human stem cell-derived pancreatic acinar and ductal organoids

The exocrine pancreas, consisting of ducts and acini, is the site of origin of pancreatitis and pancreatic ductal adenocarcinoma (PDAC). Our understanding of the genesis and progression of human pancreatic diseases, including PDAC, is limited because of challenges in maintaining human acinar and ductal cells in culture. Here we report induction of human pluripotent stem cells toward pancreatic ductal and acinar organoids that recapitulate properties of the neonatal exocrine pancreas. Expression of the PDAC-associated oncogene GNAS^R201C induces cystic growth more effectively in ductal than acinar organoids, whereas KRAS^G12D is more effective in modeling cancer in vivo when expressed in acinar compared with ductal organoids. KRAS^G12D, but not GNAS^R201C, induces acinar-to-ductal metaplasia-like changes in culture and in vivo. We develop a renewable source of ductal and acinar organoids for modeling exocrine development and diseases and demonstrate lineage tropism and plasticity for oncogene action in the human pancreas.

Drug Repurposing Opportunities in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is considered one of the deadliest tumors worldwide. The diagnosis is often possible only in the latter stages of the disease, with patients already presenting an advanced or metastatic tumor. It is also one of the cancers with poorest prognosis, presenting a five-year survival rate of around 5%. Treatment of PDAC is still a major challenge, with cytotoxic chemotherapy remaining the basis of systemic therapy. However, no major advances have been made recently, and therapeutic options are limited and highly toxic. Thus, novel therapeutic options are urgently needed. Drug repurposing is a strategy for the development of novel treatments using approved or investigational drugs outside the scope of the original clinical indication. Since repurposed drugs have already completed several stages of the drug development process, a broad range of data is already available. Thus, when compared with de novo drug development, drug repurposing is time-efficient, inexpensive and has less risk of failure in future clinical trials. Several repurposing candidates have been investigated in the past years for the treatment of PDAC, as single agents or in combination with conventional chemotherapy. This review gives an overview of the main drugs that have been investigated as repurposing candidates, for the potential treatment of PDAC, in preclinical studies and clinical trials.

Clinical Perspective on Proteomic and Glycomic Biomarkers for Diagnosis, Prognosis, and Prediction of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is known as a highly aggressive malignant disease. Prognosis for patients is notoriously poor, despite improvements in surgical techniques and new (neo)adjuvant chemotherapy regimens. Early detection of PDAC may increase the overall survival. It is furthermore foreseen that precision medicine will provide improved prognostic stratification and prediction of therapeutic response. In this review, omics-based discovery efforts are presented that aim for novel diagnostic and prognostic biomarkers of PDAC. For this purpose, we systematically evaluated the literature published between 1999 and 2020 with a focus on protein- and protein-glycosylation biomarkers in pancreatic cancer patients. Besides genomic and transcriptomic approaches, mass spectrometry (MS)-based proteomics and glycomics of blood- and tissue-derived samples from PDAC patients have yielded new candidates with biomarker potential. However, for reasons discussed in this review, the validation and clinical translation of these candidate markers has not been successful. Consequently, there has been a change of mindset from initial efforts to identify new unimarkers into the current hypothesis that a combination of biomarkers better suits a diagnostic or prognostic panel. With continuing development of current research methods and available techniques combined with careful study designs, new biomarkers could contribute to improved detection, prognosis, and prediction of pancreatic cancer.

Preclinical Models for Studying the Impact of Macrophages on Cancer Cachexia

Cancer-associated cachexia is defined by loss of weight and muscle mass, and by the potential loss of adipose tissue accompanied by insulin resistance and increased resting energy expenditure. Cachexia is most prevalent in pancreatic cancer, the third leading cause of cancer-related deaths. While various factors interact to induce cachexia, the precise mechanisms underlying this clinical condition are not fully understood. Clinically relevant animal models of cachexia are needed given the lack of standard diagnostic methods or treatments for this condition. Described in this article are in vitro and in vivo models used to study the role of macrophages in the induction of cachexia in pancreatic cancer. Included are procedures for isolating and culturing bone marrow-derived macrophages, harvesting tumor- and macrophage-derived conditioned medium, and studying the effect of conditioned medium on C2C12 myotubes. Also described are procedures involving the use of an orthotopic model of pancreatic cancer, including a method for examining skeletal muscle atrophy in this model. © 2020 Wiley Periodicals LLC. Basic Protocol 1: In vitro model of pancreatic tumor-induced cachexia using C2C12 cell lines (myotube model) Support Protocol 1: Molecular evaluation of cachectic markers in C2C12 myotubes using real-time PCR and immunoblotting Basic Protocol 2: In vivo model to study cachectic phenotype in pancreatic tumor-bearing mice Support Protocol 2: Evaluation of cachectic markers in the skeletal muscle of tumor-bearing mice.

Microbial dysbiosis and polyamine metabolism as predictive markers for early detection of pancreatic cancer

The lack of tools for early detection of pancreatic ductal adenocarcinoma (PDAC) is directly correlated with the abysmal survival rates in patients. In addition to several potential detection tools under active investigation, we tested the gut microbiome and its metabolic complement as one of the earliest detection tools that could be useful in patients at high risk for PDAC. We used a combination of 16s rRNA pyrosequencing and whole-genome sequencing of gut fecal microbiota in a genetically engineered PDAC murine model (KRASG12DTP53R172HPdxCre or KPC). Metabolic reconstruction of microbiome was done using the HUMAnN2 pipeline. Serum polyamine levels were measured from murine and patient samples using chromogenic assay. Our results showed a Proteobacterial and Firmicutes dominance in gut microbiota in early stages of PDAC development. Upon in silico reconstruction of active metabolic pathways within the altered microbial flora, polyamine and nucleotide biosynthetic pathways were significantly elevated. These metabolic products are known to be actively assimilated by the host and eventually utilized by rapidly dividing cells for proliferation validating their importance in the context of tumorigenesis. In KPC mice, as well as PDAC patients, we show significantly elevated serum polyamine concentrations. Therefore, at the early stages of tumorigenesis, there is a strong correlation between microbial changes and release of metabolites that foster host tumorigenesis, thereby fulfilling the 'vicious cycle hypothesis' of the role of microbiome in health and disease states. Our results provide a potential, precise, noninvasive tool for early detection of PDAC, which may result in improved outcomes.

Non-coding RNA biomarkers in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies, which is usually diagnosed at an advanced stage. The late disease diagnosis, the limited availability of effective therapeutic interventions and lack of robust diagnostic biomarkers, are some of the primary reasons for the dismal 5-year survival rates (∼8%) in patients with PDAC. The pancreatic cancer develops through accumulation of a series of genomic and epigenomic alterations which lead to the transformation of normal pancreatic epithelium into an invasive carcinoma - a process that can take up to 15-20 years to develop, from the occurrence of first initiating mutational event. These facts highlight a unique window of opportunity for the earlier detection of PDAC, which could allow timely disease interception and improvement in the overall survival outcomes in patients suffering from this fatal malignancy. Non-coding RNAs (ncRNAs) have been recognized to play a central role in PDAC pathogenesis and are emerging as attractive candidates for biomarker development in various cancers, including PDAC. More specifically, the ncRNAs play a pivotal role in PDAC biology as they affect tumor growth, migration, and invasion by regulating cellular processes including cell cycle, apoptosis, and epithelial-mesenchymal transition. In this review, we focus on three types of well-established ncRNAs - microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs) - and discuss their potential as diagnostic, prognostic and predictive biomarkers in PDAC.

Mutational Mosaics of Cell-Free DNA from Pancreatic Cyst Fluids

BACKGROUND

Pancreatic cyst fluids (PCFs) enriched in tumor-derived DNA are a potential source of new biomarkers. The study aimed to analyze germinal variants and mutational profiles of cell-free (cf)DNA shed into the cavity of pancreatic cysts.

METHODS

The study cohort consisted of 71 patients who underwent endoscopic ultrasound fine-needle aspiration of PCF. Five malignant cysts, 19 intraductal papillary mucinous neoplasms (IPMNs), 11 mucinous cystic neoplasms (MCNs), eight serous cystic neoplasms (SCNs), and 28 pseudocysts were identified. The sequencing of 409 genes included in Comprehensive Cancer Panel was performed using Ion Proton System. The mutation rate of the KRAS and GNAS canonical loci was additionally determined using digital PCR.

RESULTS

The number of mutations detected with NGS varied from 0 to 22 per gene, and genes with the most mutations were: TP53, KRAS, PIK3CA, GNAS, ADGRA2, and APC. The frequencies of the majority of mutations did not differ between non-malignant cystic neoplasms and pseudocysts. NGS detected KRAS mutations in malignant cysts (60%), IPMNs (32%), MCNs (64%), SCNs (13%), and pseudocysts (14%), with GNAS mutations in 20%, 26%, 27%, 13%, and 21% of samples, respectively. Digital PCR-based testing increased KRAS (68%) and GNAS (52%) mutations detection level in IPMNs, but not other cyst types.

CONCLUSIONS

We demonstrate relatively high rates of somatic mutations of cancer-related genes, including KRAS and GNAS, in cfDNA isolated from PCFs irrespectively of the pancreatic cyst type. Further studies on molecular mechanisms of pancreatic cysts malignant transformation in relation to their mutational profiles are required.

CXCR2 signaling promotes secretory cancer-associated fibroblasts in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most challenging malignancies. Desmoplasia and tumor-supporting inflammation are hallmarks of PDAC. The tumor microenvironment contributes significantly to tumor progression and spread. Cancer-associated fibroblasts (CAFs) facilitate therapy resistance and metastasis. Recent reports emphasized the concurrence of multiple subtypes of CAFs with diverse roles, fibrogenic, and secretory. C-X-C motif chemokine receptor 2 (CXCR2) is a chemokine receptor known for its role during inflammation and its adverse role in PDAC. Oncogenic Kras upregulates CXCR2 and its ligands and, thus, contribute to tumor proliferation and immunosuppression. CXCR2 deletion in a PDAC syngeneic mouse model produced increased fibrosis revealing a potential undescribed role of CXCR2 in CAFs. In this study, we demonstrate that the oncogenic Kras-CXCR2 axis regulates the CAFs function in PDAC and contributes to CAFs heterogeneity. We observed that oncogenic Kras and CXCR2 signaling alter CAFs, producing a secretory CAF phenotype with low fibrogenic features; and increased secretion of pro-tumor cytokines and CXCR2 ligands, utilizing the NF-κB activity. Finally, using syngeneic mouse models, we demonstrate that oncogenic Kras is associated with secretory CAFs and that CXCR2 inhibition promotes activation of fibrotic cells (myofibroblasts) and impact tumors in a mutation-dependent manner.

Clinical and radiological features that predict malignant transformation in cystic lesions of the pancreas: a retrospective case note review

Background: Pancreatic cystic lesions (PCL) are being detected with increasing frequency. Current methods of stratifying risk of malignant transformation are imperfect. This study aimed to determine the frequency of pancreatic malignancy in patients with PCL and define clinical and radiological features that predict malignant transformation in patients managed by surgery and/or surveillance.

Methods: A retrospective cohort of adults who were evaluated in a tertiary hepatopancreaticobiliary centre between January 2000 - December 2013 with a confirmed PCL and followed up for at least 5 years. All cystic lesions were discussed at a weekly multidisciplinary meeting.

Results: Of the 1,090 patients diagnosed with a PCL, 768 patients were included in the study: 141 patients were referred for immediate pancreatic resection, 570 entered surveillance while 57 had a malignant PCL which was unresectable at diagnosis (n=47) or were unfit for surgery (n=10). In those who were resected following presentation, malignancy was present in 38%. During follow-up 2% of those entering a surveillance programme underwent malignant transformation. Clinical and radiological features associated with a high-risk PCL included older age, symptoms, associated solid component or dilated main pancreatic duct. In intraductal papillary mucinous neoplasms, larger size was not a feature of malignant transformation (benign vs. malignant 30mm vs. 23mm; P= 0.012).

Conclusion: The sensitivity of standard diagnostic tests leading to immediate surgery for high-risk PCL (malignant or mucinous) was 92% but with a specificity of just 5%. Surveillance of PCL without high-risk features within a multidisciplinary meeting was associated with a low incidence of cancer development, supporting the use of worrisome clinical and radiological features in the initial stratification of PCL.

Precursors to Cholangiocarcinoma

Cancers of the biliary tract include intra- and extrahepatic cholangiocarcinomas and gallbladder cancer. Biliary tract cancers are diseases with unfavorable prognoses. In recent years, several lesions have been described as precursors that precede biliary cancers. They include flat and microscopic lesions known as biliary intraepithelial neoplasia, macroscopic and tumor-forming intraductal papillary biliary neoplasia, intraductal tubular neoplasia, and mucinous cystic neoplasm of the bile duct. These conditions are rarely diagnosed, while their natural history and progression to cancer have yet to be adequately characterized. This review examines the epidemiology, pathology, molecular biology, diagnosis, and therapy of these various precursors. Further research is required if we are to better understand this evolving field and improve the prevention and early detection of bile duct cancer.

Nanomedicine for Imaging and Therapy of Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma has the worst outcome among all cancer types, with a 5-year survival rate as low as 10%. The lethal nature of this cancer is a result of its silent onset, resistance to therapies, and rapid spreading. As a result, most patients remain asymptomatic and present at diagnosis with an already infiltrating and incurable disease. The tumor microenvironment, composed of a dense stroma and of disorganized blood vessels, coupled with the dysfunctional signal pathways in tumor cells, creates a set of physical and biological barriers that make this tumor extremely hard-to-treat with traditional chemotherapy. Nanomedicine has great potential in pancreatic adenocarcinoma, because of the ability of nano-formulated drugs to overcome biological barriers and to enhance drug accumulation at the target site. Moreover, monitoring of disease progression can be achieved by combining drug delivery with imaging probes, resulting in early detection of metastatic patterns. This review describes the latest development of theranostic formulations designed to concomitantly treat and image pancreatic cancer, with a specific focus on their interaction with physical and biological barriers.

Pancreatic fat content may increase the risk of imaging progression in low-risk branch duct intraductal papillary mucinous neoplasm

OBJECTIVE

To identify risk factors of imaging progression (increase in cyst size or main pancreatic duct size, or a new mural nodule) in low-risk branch duct intraductal papillary mucinous neoplasm (BD-IPMN), including obesity-related factors such as pancreatic fat content.

METHODS

Our hospital databases were searched for patients who had completed health checkup, including upper abdominal magnetic resonance imaging (MRI) over 48 months (August 2012 to July 2016). Individuals with BD-IPMN without worrisome features and high-risk stigmata who underwent surveillance with at least one follow-up MRI, irrespective of the follow-up period, were included. Pancreatic computed tomography attenuation indexes were defined as the difference between the pancreas and spleen attenuation (P - S) and the pancreas to spleen attenuation ratio (P/S).

RESULTS

Among 75 patients diagnosed as having low-risk BD-IPMN, during a median follow-up of 36 months, 11 (15%) had imaging progression in cyst size, including two with worrisome features. A multivariate logistic analysis showed that the initial cyst size and both indexes (P - S, or P/S) were significantly associated with imaging progression in IPMN, respectively (Model 1: odds ratio [OR] 1.188, 95% confidence interval [CI] 1.060-1.331, P = 0.003; OR 0.871, 95% CI 0.776-0.977, P = 0.019; Model 2: OR 1.186, 95% CI 1.064-1.322, P = 0.002; OR 0.002, 95% CI 0.000-0.970, P = 0.049).

CONCLUSIONS

Pancreatic fat content and initial cyst size were significantly associated with imaging progression in low-risk BD-IPMN. Revisions of international consensus Fukuoka guidelines might be customized based on initial cyst size and pancreatic fat content.

Lipopolysaccharide induces the differentiation of hepatic progenitor cells into myofibroblasts constitutes the hepatocarcinogenesis-associated microenvironment

Hepatocellular carcinoma (HCC) generally occurs in the presence of chronic liver injury, often as a sequela of liver fibrosis. Hepatic progenitor cells (HPCs) are known to be capable of forming both hepatocytes and cholangiocytes in chronic liver injury, which are also considered a source of myofibroblasts and tumor-initiating cells, under carcinogenic circumstances. However, the underlying mechanisms that activate HPCs to give rise to HCC are still unclear. In current study, the correlation between HPCs activation and liver fibrosis and carcinogenesis was investigated in rats and human specimens. We analyzed the role of HPCs in tumorigenesis, by transplanting exogenous HPCs in a diethylnitrosamine-induced rat HCC model. Our data indicated that HPC activation correlated with hepatic fibrosis and hepatocarcinogenesis. We further found that exogenous HPC infusion promoted liver fibrosis and hepatocarcinogenesis, while lipopolysaccharides (LPS) played an important role in this process. However, results of our study indicated that LPS did not induce HPCs to form tumor in nude mice directly. Rather, LPS induced myofibroblast-like morphology in HPCs, which enhanced the tumorigenic potential of HPCs. Further experiments showed that LPS/Toll-like receptor 4 (TLR4) signaling mediated the differentiation of HPCs into myofibroblasts and enhanced the production of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), which led to the aberrant expression of Ras and p53 signaling pathways in HPCs, and finally, promoted the proliferation and malignant transformation of HPCs, by long non-coding RNA regulation. Besides, examination of HCC clinical samples demonstrated that IL-6 and TNF-α production correlated with HPC activation, hepatic fibrosis, and HCC recurrence. Our study indicates that both myofibroblasts and tumor cells are derived from HPCs. HPC-derived myofibroblasts create tumor microenvironment and contribute to the proliferation and malignant transformation of HPCs. Furthermore, LPS present in the chronic liver inflammation microenvironment might play an important role in hepatocarcinogenesis, by regulating the plastic potential of HPCs.

Characteristics and Clinical Outcomes of Individuals at High Risk for Pancreatic Cancer: A Descriptive Analysis from a Comprehensive Cancer Center

Pancreatic cancer (PC), a leading cause of cancer-related deaths in the United States, is typically diagnosed at an advanced stage. To improve survival, there is an unmet need to detect pre-malignant lesions and early invasive disease. Prime populations to study for early detection efforts include cohorts of high risk individuals (HRI): those with increased risk to develop pre-malignant pancreatic cysts and PC because of a familial or hereditary predisposition to the disease and those in the general population of sporadic cases who are incidentally found to harbor a pre-malignant pancreatic cyst. The objective of this study was to describe the characteristics and clinical outcomes of cohorts of HRI identified at Moffitt Cancer Center. We set out to determine the uptake of screening, the prevalence and characteristics of solid and cystic pancreatic lesions detected via screening or as incidental findings, and the age at which lesions were detected. Of a total of 329 HRI, roughly one-third were found to have pancreatic lesions, most of which constituted pre-malignant cysts known as intraductal papillary mucinous neoplasms. Individuals with the highest genetic risk for PC were found to have smaller cysts at a much earlier age than sporadic cases with incidental findings; however, many individuals at high genetic risk did not have abdominal imaging reports on file. We also identified a subset of HRI at moderate genetic risk for PC that were found to have cystic and solid pancreatic lesions as part of a diagnostic work-up rather than a screening protocol. These findings suggest the pancreatic research community should consider expanding criteria for who should be offered screening. We also emphasize the importance of continuity of care between cancer genetics and gastrointestinal oncology clinics so that HRI are made aware of the opportunities related to genetic counseling, genetic testing, and screening.

Familial Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), although a rare disease, has a poor prognosis. With 5-year overall survival of 8%, there is a critical need to detect PDAC early or at a premalignant stage. Current screening methods are largely imaging based, but a more focused screening approach based on modifiable and nonmodifiable risk factors may improve the efficacy and likely outcomes of screening. In addition, the pathologic mechanisms that lead to the development of PDAC are discussed in an effort to further understand the targets of pancreatic cancer screening. The focus of this article will be inherited pancreatic cancer syndromes and familial pancreatic cancer, which together compose up to 10% of PDAC. Understanding the methods and targets of PDAC screening in high-risk individuals may translate to improved morbidity and mortality.

Preoperative next-generation sequencing of pancreatic cyst fluid is highly accurate in cyst classification and detection of advanced neoplasia

OBJECTIVE

DNA-based testing of pancreatic cyst fluid (PCF) is a useful adjunct to the evaluation of pancreatic cysts (PCs). Mutations in KRAS/GNAS are highly specific for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), while TP53/PIK3CA/PTEN alterations are associated with advanced neoplasia. A prospective study was performed to evaluate preoperative PCF DNA testing.

DESIGN

Over 43-months, 626 PCF specimens from 595 patients were obtained by endoscopic ultrasound (EUS)-fine needle aspiration and assessed by targeted next-generation sequencing (NGS). Molecular results were correlated with EUS findings, ancillary studies and follow-up. A separate cohort of 159 PCF specimens was also evaluated for KRAS/GNAS mutations by Sanger sequencing.

RESULTS

KRAS/GNAS mutations were identified in 308 (49%) PCs, while alterations in TP53/PIK3CA/PTEN were present in 35 (6%) cases. Based on 102 (17%) patients with surgical follow-up, KRAS/GNAS mutations were detected in 56 (100%) IPMNs and 3 (30%) MCNs, and associated with 89% sensitivity and 100% specificity for a mucinous PC. In comparison, KRAS/GNAS mutations by Sanger sequencing had a 65% sensitivity and 100% specificity. By NGS, the combination of KRAS/GNAS mutations and alterations in TP53/PIK3CA/PTEN had an 89% sensitivity and 100% specificity for advanced neoplasia. Ductal dilatation, a mural nodule and malignant cytopathology had lower sensitivities (42%, 32% and 32%, respectively) and specificities (74%, 94% and 98%, respectively).

CONCLUSIONS

In contrast to Sanger sequencing, preoperative NGS of PCF for KRAS/GNAS mutations is highly sensitive for IPMNs and specific for mucinous PCs. In addition, the combination of TP53/PIK3CA/PTEN alterations is a useful preoperative marker for advanced neoplasia.

Identification of Serum Biomarker Panels for the Early Detection of Pancreatic Cancer

BACKGROUND

Pancreatic cancer is a deadly disease for which available biomarkers, such as CA19-9, lack the desired sensitivity and specificity for early detection. Additional biomarkers are needed to improve both its sensitivity and specificity.

METHODS

Multiplex immunoassays were developed for selected biomarkers using a Bio-Plex 200 system, and analytical performance was optimized. All proteins were analyzed in sera of patients diagnosed with pancreatic ductal adenocarcinoma (PDAC; n = 188) or benign pancreatic conditions (131) and healthy controls (89). The clinical performance of these markers was evaluated individually or in combination for their ability to complement CA19-9 for the early detection of pancreatic cancer.

RESULTS

A 6-plex immunoassay was developed with negligible cross-reactivity, wide dynamic range, recovery of 89% to 104%, and intra-assay and interassay precision of 10.2% to 19.6% and 13.7% to 29.3%, respectively. Individually, the best biomarkers to separate PDAC early stage from chronic pancreatitis or intraductal papillary mucinous neoplasm (IPMN) were CA19-9 and MIA or CA19-9 and MIC-1. Logistic regression modeling selected the two-marker panels that significantly improved the individual biomarker performance in discriminating PDAC early stage from chronic pancreatitis (AUC_CA19-9+MIA = 0.86 vs. AUC_CA19-9 = 0.81 or AUC_MIA = 0.75 only, P < 0.05) or IPMN (AUC_CA19-9+MIC-1 = 0.81 vs. AUC_CA19-9 = 0.75 or AUC_MIC-1 = 0.73 only, P < 0.05). It was observed that osteopontin (OPN) outperformed CA19-9 in separating IPMN from chronic pancreatitis (AUC_OPN = 0.80 vs. AUC_CA19-9 = 0.70, P < 0.01).

CONCLUSIONS

The biomarker panels evaluated by assays with high analytical performance demonstrated potential complementary values to CA19-9, warranting additional clinical validation to determine their role in early detection of pancreatic cancer.

IMPACT

The validated biomarker panels could lead to earlier intervention and better outcomes.

Familial Pancreatic Cancer and the Future of Directed Screening

Pancreatic cancer (PC) is the third most common cause of cancer-related death in the United States and the 12th most common worldwide. Mortality is high, largely due to late stage of presentation and suboptimal treatment regimens. Approximately 10% of PC cases have a familial basis. The major genetic defect has yet to be identified but may be inherited by an autosomal dominant pattern with reduced penetrance. Several known hereditary syndromes or genes are associated with an increased risk of developing PC and account for approximately 2% of PCs. These syndromes include the hereditary breast-ovarian cancer syndrome, Peutz-Jeghers syndrome, familial atypical multiple mole melanoma, Lynch syndrome, familial polyposis, ataxia-telangiectasia, and hereditary pancreatitis. Appropriate screening using methods such as biomarkers or imaging, with endoscopic ultrasound and magnetic resonance imaging, may assist in the early detection of neoplastic lesions in the high-risk population. If these lesions are detected and treated before the development of invasive carcinoma, PC disease morbidity and mortality may be improved. This review will focus on familial PC and other hereditary syndromes implicated in the increased risk of PC; it will also highlight current screening methods and the future of new screening modalities.

Current Molecular and Genetic Aspects of Pancreatic Cancer, the Role of Metastasis Associated Proteins (MTA): A Review

Purpose/aim: To focus on current molecular and genetic aspects and MTA proteins, since pancreatic cancer is a lethal malignant with poor prognosis. Early diagnosis is essential step, contributing to potential curative resection.

MATERIALS AND METHODS

A PubMed search of relevant articles published up to August 2016 was performed to identify current information about pancreatic cancer regarding molecular biomarkers, with emphasis on carcinogenesis, novel therapeutic targets, and MTA proteins.

RESULTS

Understanding the mechanisms involved in the process of carcinogenesis at the molecular level and the recognition of various oncogenes has opened new horizons for both diagnosis and targeted therapy. Metastasis associated (MTA) proteins (MTA1, MTA2, MTA3) comprise a well-established family of biomarkers. The oncogene MTA1 and its expression product MTA1 protein are the most important and adequately studied in the current research. It defines the growth, local invasiveness, lymphatic spread, and metastatic capacity of various malignancies such as colorectal or gastric cancer including also pancreatic cancer. This protein is associated with malignant potential and biological behavior. Consequently, it could contribute to cancer detection since the first stages of carcinogenesis, as well as in prediction of its malignant differentiation grade. The pre-operative information of the possibility of lymph node involvement may also affect the attempt and the extent of curative resection and lymphadenectomy.

CONCLUSIONS

Carcinogenesis and implicated oncogenes, either activators or repressors, concentrate much research interest, as well as being useful as biomarkers and for targeted therapy. MTA proteins could become useful diagnostic and prognostic biomarkers in current management of pancreatic cancer.

Classification, Morphology, Molecular Pathogenesis, and Outcome of Premalignant Lesions of the Pancreas

CONTEXT

- Invasive pancreatic ductal adenocarcinoma has a greater than 90% mortality rate at 5 years. Understanding noninvasive, curable precursor lesions gives us the best hope for reducing mortality from pancreatic ductal adenocarcinoma. The 3 pancreatic precursor lesions that have been well studied include intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia.

OBJECTIVE

- To give an update on the latest clinical, molecular, and pathologic advances in intraductal papillary mucinous neoplasm, mucinous cystic neoplasm, and pancreatic intraepithelial neoplasia for the general surgical pathologist.

DATA SOURCES

- The current literature was analyzed and the authors' experiences with institutional and consult material were incorporated.

CONCLUSIONS

- Our understanding of the molecular alterations that lead from pancreatic precursor lesion to invasive carcinoma continues to evolve. These advances aid clinicians in their treatment decisions and researchers in their search for actionable, druggable targets.

Pancreatic Cancer: Molecular Characterization, Clonal Evolution and Cancer Stem Cells

Pancreatic Ductal Adenocarcinoma (PDAC) is the fourth most common cause of cancer-related death and is the most lethal of common malignancies with a five-year survival rate of <10%. PDAC arises from different types of non-invasive precursor lesions: intraductal papillary mucinous neoplasms, mucinous cystic neoplasms and pancreatic intraepithelial neoplasia. The genetic landscape of PDAC is characterized by the presence of four frequently-mutated genes: KRAS, CDKN2A, TP53 and SMAD4. The development of mouse models of PDAC has greatly contributed to the understanding of the molecular and cellular mechanisms through which driver genes contribute to pancreatic cancer development. Particularly, oncogenic KRAS-driven genetically-engineered mouse models that phenotypically and genetically recapitulate human pancreatic cancer have clarified the mechanisms through which various mutated genes act in neoplasia induction and progression and have led to identifying the possible cellular origin of these neoplasias. Patient-derived xenografts are increasingly used for preclinical studies and for the development of personalized medicine strategies. The studies of the purification and characterization of pancreatic cancer stem cells have suggested that a minority cell population is responsible for initiation and maintenance of pancreatic adenocarcinomas. The study of these cells could contribute to the identification and clinical development of more efficacious drug treatments.

Duct- and Acinar-Derived Pancreatic Ductal Adenocarcinomas Show Distinct Tumor Progression and Marker Expression

The cell of origin of pancreatic ductal adenocarcinoma (PDAC) has been controversial. Here, we show that identical oncogenic drivers trigger PDAC originating from both ductal and acinar cells with similar histology but with distinct pathophysiology and marker expression dependent on cell of origin. Whereas acinar-derived tumors exhibited low AGR2 expression and were preceded by pancreatic intraepithelial neoplasias (PanINs), duct-derived tumors displayed high AGR2 and developed independently of a PanIN stage via non-mucinous lesions. Using orthotopic transplantation and chimera experiments, we demonstrate that PanIN-like lesions can be induced by PDAC as bystanders in adjacent healthy tissues, explaining the co-existence of mucinous and non-mucinous lesions and highlighting the need to distinguish between true precursor PanINs and PanIN-like bystander lesions. Our results suggest AGR2 as a tool to stratify PDAC according to cell of origin, highlight that not all PanIN-like lesions are precursors of PDAC, and add an alternative progression route to the current model of PDAC development.

Deciphering the link between PI3K and PAK: An opportunity to target key pathways in pancreatic cancer?

The development of personalised therapies has ushered in a new and exciting era of cancer treatment for a variety of solid malignancies. Yet pancreatic ductal adenocarcinoma (PDAC) has failed to benefit from this paradigm shift, remaining notoriously refractory to targeted therapies. Chemotherapy is the cornerstone of management but can offer only modest survival benefits of a few months with 5-year survival rates rarely exceeding 3%. Despite these disappointing statistics, significant strides have been made towards understanding the complex biology of pancreatic cancer, with deep genomic sequencing identifying novel genetic aberrations and key signalling pathways. The PI3K-PDK1-AKT pathway has received great attention due to its prominence in carcinogenesis. However, efforts to target several components of this network have resulted in only a handful of drugs demonstrating any survival benefit in solid tumors; despite promising pre-clinical results. p-21 activated kinase 4 (PAK4) is a gene that is recurrently amplified or overexpressed in PDAC and both PAK4 and related family member PAK1, have been linked to aberrant RAS activity, a common feature in pancreatic cancer. As regulators of PI3K, PAKs have been highlighted as a potential prognostic marker and therapeutic target. In this review, we discuss the biology of pancreatic cancer and the close interaction between PAKs and the PI3K pathway. We also suggest proposals for future research that may see the development of effective targeted therapies that could finally improve outcomes for this disease.

Diabetes mellitus in intraductal papillary mucinous neoplasm of the pancreas is associated with high-grade dysplasia and invasive carcinoma

BACKGROUND

While the association between Diabetes Mellitus (DM) and pancreatic ductal adenocarcinoma is well recognized, its importance in intraductal papillary mucinous neoplasm of the pancreas (IPMN) is not well-defined. We sought to examine the associations of DM with degree of dysplasia and morphological subtypes in IPMN.

METHODS

In 454 patients with resected IPMN, we evaluated associations of DM with high-grade dysplasia (HGD), invasive carcinoma, precursor epithelial subtype (gastric, intestinal, oncocytic, pancreatobiliary), and histological type of invasive carcinomas (tubular, colloid, oncocytic) using logistic regression. We performed multivariate analyses adjusting for worrisome features and high-risk stigmata of malignancy in a subset of 289 patients with annotated radiological characteristics.

RESULTS

The prevalence of DM in our study was 34%. DM was significantly associated with HGD (OR 2.02, 95% CI 1.02-4.01, P = 0.045) and invasive carcinoma (OR 2.05, 95% CI 1.08-3.87, P = 0.027) after adjusting for worrisome features. Compared to patients without DM, those with recent-onset DM (≤5 years before surgery) had 6.9-fold (95% CI 2.38-19.92, P < 0.001) higher risk of invasive carcinoma. DM was associated with increased likelihood of intestinal-type precursor epithelium (OR 1.63, 95% CI 1.07-2.47, P = 0.022) and colloid carcinomas (OR 2.46, 95% CI 1.01-5.99, P = 0.047) CONCLUSION: Preoperative DM was associated with significantly higher risk of HGD and invasive carcinoma in resected IPMN, and risk of invasive carcinoma was highest in patients with recent-onset DM. Patients with DM were more likely to harbor intestinal-type IPMN and colloid carcinomas. Our findings suggest that a diagnosis of DM in patients with IPMN may warrant more aggressive surveillance.

Molecular Diagnostics in the Evaluation of Pancreatic Cysts

Within the past few decades, there has been a dramatic increase in the detection of incidental pancreatic cysts. It is reported a pancreatic cyst is identified in up to 2.6% of abdominal scans. Many of these cysts, including serous cystadenomas and pseudocysts, are benign and can be monitored clinically. In contrast, mucinous cysts, which include intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, have the potential to progress to pancreatic adenocarcinoma. In this review, we discuss the current management guidelines for pancreatic cysts, their underlying genetics, and the integration of molecular testing in cyst classification and prognostication.

IL2RG, identified as overexpressed by RNA-seq profiling of pancreatic intraepithelial neoplasia, mediates pancreatic cancer growth

Pancreatic ductal adenocarcinoma evolves from precursor lesions, the most common of which is pancreatic intraepithelial neoplasia (PanIN). We performed RNA-sequencing analysis of laser capture microdissected PanINs and normal pancreatic duct cells to identify differentially expressed genes between PanINs and normal pancreatic duct, and between low-grade and high-grade PanINs. One of the most highly overexpressed transcripts identified in PanIN is interleukin-2 receptor subunit gamma (IL2RG) encoding the common gamma chain, IL2Rγ. CRISPR-mediated knockout of IL2RG in orthotopically implanted pancreatic cancer cells resulted in attenuated tumor growth in mice and reduced JAK3 expression in orthotopic tumors. These results indicate that IL2Rγ/JAK3 signaling contributes to pancreatic cancer cell growth in vivo.

Pancreatic cancer screening: Still a delusion?

Pancreatic adenocarcinoma represents the fourth most common cause of cancer mortality and death due to pancreatic cancer (PC) have increased since 2003. Its incidence has also raised about 30% in the past decade and it is expected to become the second cause of cancer mortality by 2020 in the USA. Most PC present with metastatic disease and improvements in treatment outcomes for this group have been disappointing. These observations support the idea that screening to identify patients at an earlier stage might be an important strategy in improving overall PC outcomes. Many protocols have been tested, nevertheless, by now there is no effective screening program. Given the overall low incidence of disease and the current lack of accurate, inexpensive and noninvasive screening tests, the consensus is that widespread population-based screening for PC in the general population or in patients with only one affected first-degree relative is neither practicable nor indicated in most countries. However, a different scenario is screening patients with higher risk for PC, most of them with hereditary conditions predisposing the development of this neoplasia. In fact, some guidelines are now available helping to select these individuals at risk and to screen them, in order to achieve early detection of PC.

Novel Biomarkers for Pancreatic Cysts

With increased utilization and ongoing advancements in cross-sectional abdominal imaging, the identification of a pancreatic cyst has become a frequent finding. While many pancreatic cysts are associated with a benign clinical course, others may transform into pancreatic ductal adenocarcinoma. However, distinguishing a benign from a malignant pancreatic cyst or pancreatic cyst with malignant potential on the basis of standard clinical findings, imaging parameters and ancillary studies can be challenging. Hence, a significant interest within the past decade has been the identification of novel biomarkers to accurately classify and prognosticate a pancreatic cyst. Within this review, we discuss novel DNA, miRNA, protein and metabolite biomarkers, and their relevance in clinical practice. In addition, we focus on future areas of research that have the potential to change pancreatic cyst management.

Comparing 3 guidelines on the management of surgically removed pancreatic cysts with regard to pathological outcome

BACKGROUND AND AIMS

Currently, 3 guidelines are available for the management of pancreatic cysts. These guidelines vary in their indication for resection of high-risk cysts. We retrospectively compared the final pathologic outcome of surgically removed pancreatic cysts with the indications for resection according to 3 different guidelines.

METHODS

Patients who underwent pancreatic resection were extracted from our prospective pancreatic cyst database (2006-present). The final histopathologic diagnosis was compared with the initial indication for surgery stated by the guidelines of the International Association of Pancreatology (IAP), European Study Group on Cystic tumors of the Pancreas and American Gastroenterological Association (AGA). We considered surgery in retrospect justified for malignancy, high-grade dysplasia, solid pseudopapillary neoplasms, neuroendocrine tumors or symptom improvement. Furthermore, we evaluated the patients with suspected intraductal papillary mucinous neoplasm (IPMN) separately.

RESULTS

Overall, 115 patients underwent pancreatic resection. The preoperative diagnosis was correct in 83 of 115 patients (72%) and differentiation between benign and premalignant in 99 of 115 patients (86%). In retrospect, surgery was justified according to the aforementioned criteria in 52 of 115 patients (45%). For patients with suspected IPMN (n = 75) resection was justified in 36 of 67 (54%), 36 of 68 (53%), and 32 of 54 (59%) of patients who would have had surgery based on the IAP, European, or AGA guidelines, respectively. The AGA guideline would have avoided resection in 21 of 75 (28%) patients, versus 8 of 75 (11%) and 7 of 75 (9%) when the IAP or European guideline would have been applied strictly. Nevertheless, 4 of 33 patients (12%) with high-grade dysplasia or malignancy would have been missed with the AGA guidelines, compared with none with the IAP or European guidelines.

CONCLUSION

Although fewer patients undergo unnecessary surgery based on the AGA guidelines, the risk of missing malignancy or high-grade dysplasia with this guideline seems considerably high.