Insights into the Pathogenesis of Pancreatic Cystic Neoplasms

A senescence restriction point acting on chromatin integrates oncogenic signals

We identify a senescence restriction point (SeRP) as a critical event for cells to commit to senescence. The SeRP integrates the intensity and duration of oncogenic stress, keeps a memory of previous stresses, and combines oncogenic signals acting on different pathways by modulating chromatin accessibility. Chromatin regions opened upon commitment to senescence are enriched in nucleolar-associated domains, which are gene-poor regions enriched in repeated sequences. Once committed to senescence, cells no longer depend on the initial stress signal and exhibit a characteristic transcriptome regulated by a transcription factor network that includes ETV4, RUNX1, OCT1, and MAFB. Consistent with a tumor suppressor role for this network, the levels of ETV4 and RUNX1 are very high in benign lesions of the pancreas but decrease dramatically in pancreatic ductal adenocarcinomas. The discovery of senescence commitment and its chromatin-linked regulation suggests potential strategies for reinstating tumor suppression in human cancers.

Exploring the therapeutic potential of focal adhesion kinase inhibition in overcoming chemoresistance in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is among the leading causes of cancer-related deaths worldwide. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase often overexpressed in PDAC. FAK has been linked to cell migration, survival, proliferation, angiogenesis and adhesion. This review first highlights the chemoresistant nature of PDAC. Second, the role of FAK in PDAC cancer progression and resistance is carefully described. Additionally, it discusses recent developments of FAK inhibitors as valuable drugs in the treatment of PDAC, with a focus on diamine-substituted-2,4-pyrimidine-based compounds, which represent the most potent class of FAK inhibitors in clinical trials for the treatment of PDAC disease. To conclude, relevant computational studies performed on FAK inhibitors are reported to highlight the key structural features required for interaction with the protein, with the aim of optimizing this novel targeted therapy.

The Natural Course of Pancreatic Cysts in Inflammatory Bowel Disease: Results of a Long-term Follow-up

OBJECTIVES

The natural course of pancreatic cysts in inflammatory bowel disease (IBD) is unknown. We aim to describe the natural course of pancreatic cysts in IBD and evaluate long-term outcomes.

METHODS

A database of patients with abdominal imaging diagnosis of pancreatic cysts (2008-2019) was reviewed. Patients with IBD and pancreatic cysts (study group) and pancreatic cysts without IBD (controls) were selected. Outcomes were measured at 1, 3, 5, and 10 years. Several logistic regression models were used for analysis.

RESULTS

Of the 1789 patients evaluated, 1690 had pancreatic cysts without IBD, and 78 had IBD and pancreatic cysts. Majority of cysts were intraductal papillary mucinous neoplasms. Patients with IBD and pancreatic cysts were more likely to be diagnosed with pancreatic cysts at a younger age (P < 0.001) and were more likely to undergo surgical intervention at a younger age (P < 0.001).

CONCLUSIONS

This is the first study to evaluate the natural course of pancreatic cysts in IBD patients. Patients with IBD were more likely to have pancreatic cysts detected at a younger age. Despite the early presentation, there were no differences in long-term outcomes. Patients with IBD with pancreatic cysts should be managed similarly to those without IBD.

Liquid Biopsy as a Prognostic and Theranostic Tool for the Management of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinomas (PDAC) represent one of the deadliest cancers worldwide. Survival is still low due to diagnosis at an advanced stage and resistance to treatment. Herein, we review the main types of liquid biopsy able to help in both prognosis and adaptation of treatments.

Pancreatic and hepatobiliary manifestations of nonalcoholic fatty pancreatic disease: a referral multi-center experience

BACKGROUND

Nonalcoholic fatty pancreatic disease (NAFPD) is an increasingly recognized disease with accumulating evidence of associated co-morbidities. However, data linked with other pancreatic and hepatobiliary disorders are still being studied.

AIMS

To investigate the association of pancreato-hepato-biliary disorders with NAFPD.

METHODS

At two Israeli medical centers, a total of 569 patients were analyzed who underwent endoscopic ultrasound for hepatobiliary indications. They were divided into groups depending on the presence or absence of NAFPD.

RESULTS

Seventy-eight patients (13.7%) had NAFPD (NAFPD group) vs. 491 patients (86.3%) without (non-NAFPD group). NAFPD was significantly associated with obesity [odds ratio (OR) 4.98, 95% confidence interval (CI) 3.02-8.24, P < 0.0001], hypertension (OR 2.55, 95% CI 1.57-4.15, P = 0.0002), active smoking (OR 2.02, 95% CI 1.04-3.93, P = 0.03), and hyperlipidemia (OR 2.86, 95% CI 1.58-5.18, P = 0.0005). On multivariate regression analysis: fatty liver (OR 5.49, 95% CI 2.88-10.49, P < 0.0001), main duct intraductal papillary mucinous neoplasm (M-IPMN) (OR 2.69, 95% CI 1.05-6.9, P = 0.04), and gallstones (OR 1.93, 95% CI 1.1-3.38, P = 0.02) were the most endoscopically and ultrasonographically detected diseases that significantly correlated with NAFPD.

CONCLUSION

NAFPD was associated with several diseases, most importantly the premalignant M-IPMN. Further investigation for these coexisting diseases should be considered.

Models of pancreatic ductal adenocarcinoma

Although pancreatic cancer remains to be a leading cause of cancer-related deaths in many industrialized countries, there have been major advances in research over the past two decades that provided a detailed insight into the molecular and developmental processes that govern the genesis of this highly malignant tumor type. There is a continuous need for the development and analysis of preclinical and genetically engineered pancreatic cancer models to study the biological significance of new molecular targets that are identified using various genome-wide approaches and to better understand the mechanisms by which they contribute to pancreatic cancer onset and progression. Following an introduction into the etiology of pancreatic cancer, the molecular subtypes, and key signaling pathways, this review provides an overview of the broad spectrum of models for pancreatic cancer research. In addition to conventional and patient-derived xenografting, this review highlights major milestones in the development of chemical carcinogen-induced and genetically engineered animal models to study pancreatic cancer. Particular emphasis was placed on selected research findings of ligand-controlled tumor models and current efforts to develop genetically engineered strains to gain insight into the biological functions of genes at defined developmental stages during cancer initiation and metastatic progression.

Pancreatic Ductal Adenocarcinoma (PDAC) Organoids: The Shining Light at the End of the Tunnel for Drug Response Prediction and Personalized Medicine

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) causes massive medical problems because of late diagnosis and limited responsiveness to standard chemotherapeutic treatments. This makes PDAC one of the major causes of death by cancer. To address this problem, novel tools for early diagnosis and therapy are needed. The recent development of PDAC organoids, which represent micro-scale mini-tumors, offers promising new options for personalized drug-testing based on primary PDAC patient material. This overview article summarizes and discusses the current state-of-the-art in exploiting the organoid technology to improve clinical management of PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) represents 90% of pancreatic malignancies. In contrast to many other tumor entities, the prognosis of PDAC has not significantly improved during the past thirty years. Patients are often diagnosed too late, leading to an overall five-year survival rate below 10%. More dramatically, PDAC cases are on the rise and it is expected to become the second leading cause of death by cancer in western countries by 2030. Currently, the use of gemcitabine/nab-paclitaxel or FOLFIRINOX remains the standard chemotherapy treatment but still with limited efficiency. There is an urgent need for the development of early diagnostic and therapeutic tools. To this point, in the past 5 years, organoid technology has emerged as a revolution in the field of PDAC personalized medicine. Here, we are reviewing and discussing the current technical and scientific knowledge on PDAC organoids, their future perspectives, and how they can represent a game change in the fight against PDAC by improving both diagnosis and treatment options.

RNF43 Mutations in IPMN Cases: A Potential Prognostic Factor

An intraductal papillary mucinous neoplasm (IPMN) is a common pancreatic precursor lesion, and it often harbors mutations in KRAS, GNAS, and RNF43. To clarify the molecular profiles of IPMNs, we conducted mutation analysis of KRAS, GNAS, and RNF43 in 61 IPMN formalin-fixed, paraffin-embedded (FFPE) specimens. The mutation rates of codons 12, 13, and 61 in KRAS and codon 201 in GNAS were detected by Sanger sequencing. Next-generation sequencing was performed on RNF43, and the results were further verified by Sanger sequencing. We identified KRAS and GNAS mutations in 35 (57%) and 40 (66%) IPMN cases, respectively. GNAS mutations were significantly correlated with the morphologic subtype (P < 0.001) and were more prevalent in the intestinal subtype (93%) than in the gastric (55%) and pancreatobiliary subtypes (44%) but were absent in the oncocytic subtype. RNF43 mutations were found in 5 cases (8%), all of which occurred in high-grade dysplasia and invasive lesions (2/5 and 3/5). All 5 cases harboring RNF43 mutations also exhibited GNAS mutations. RNF43 mutations were associated with a worse prognosis in invasive IPMN patients (P = 0.002), while KRAS and GNAS mutations did not affect the prognosis of patients.

Metachronous intraductal papillary mucinous neoplasms disseminate via the pancreatic duct following resection

Metachronous development of intraductal papillary mucinous neoplasms in the remnant pancreas following resection is a significant clinical burden. Our aim was to characterize the clinicopathological and molecular features of the patients with metachronous tumor development to identify predictive factors and the possible route(s) of dissemination. Seventy-four patients who underwent resection of intraductal papillary mucinous neoplasms with no invasive compartment or associated carcinoma were retrospectively analyzed. In patients with metachronous tumor development, targeted sequencing of 18 genes associated with pancreatic tumorigenesis and immunohistochemical detection of four proteins (p53, SMAD4, p16, and β-catenin) were performed on both primary and metachronous tumors. The distributions of microscopic neoplastic lesions were examined at surgical margins and in apparently normal tissue apart from the primary tumor. During the median follow-up period of 52 months, 9 patients (12%) developed metachronous tumors in the remnant pancreas. Primary tumors located in the body/tail of the pancreas (odds ratio, 15; 95% confidence interval, 1.6-131) and of the pancreatobiliary type (odds ratio, 6.1; 95% confidence interval, 1.1-35.7) were identified as significant risk factors for subsequent metachronous tumor development. Eight of the nine patients shared molecular aberrations between their primary and metachronous tumors, suggesting migrations from the primary tumor to the pancreatic duct as the cause of metachronous tumor development. Our data suggest that these post-resection metachronous tumors develop by skip dissemination of the primary tumor, potentially via the pancreatic duct. The development of strategies to better predict and prevent this form of tumor progression is necessary.

Molecular markers contribute to the clinical diagnosis for pancreatic cystic neoplasms

A pancreatic cystic neoplasm (PCN) is a rare pancreatic disease. Malignant PCNs are usually identified incidentally while evaluating other lesions. However, PCNs are being identified more frequently owing to the increased use of abdominal imaging. Malignant PCNs have complicated and diverse biological behaviors, including various malignant risk factors, diverse molecular features, natural history, and complex pathological classifications. Although many diagnostic methods, such as cross-sectional imaging and endoscopic evaluation, have been developed, malignant PCNs are still difficult to differentiate from benign tumors. On searching for related articles in the recent decade, we found that some molecular biomarkers such as carcinoembryonic antigen could be useful for discriminating between malignant tumors and benign tumors. However, cytopathologic evaluation is the most useful method for differentiating between benign and malignant lesions. Although cytopathologic evaluation has a specificity of 100% for identifying malignancies, its accuracy is often hampered by the low cellularity of PCN cells in the cystic fluid. Herein, we review the progress in the use of cellular and molecular markers for the accurate identification of PCNs.

Stratifying Intraductal Papillary Mucinous Neoplasms by Cyst Fluid Analysis: Present and Future

A significant proportion of patients with intraductal papillary mucinous neoplasms (IPMNs) undergo surgical resection in order to prevent or treat pancreatic cancer at the risk of significant perioperative morbidity. Efforts have been made to stratify the potential risk of malignancy based on the clinical and radiographic features of IPMN to delineate which cysts warrant resection versus observation. An analysis of the cyst fluid obtained by preoperative endoscopic examination appears to be correlative of cyst type and risk, whereas serum markers and radiographic findings have not yet reached a level of sensitivity or specificity that proves they are clinically meaningful. In this review, we investigate the current cyst fluid analysis studies and present those that have shown promise in effectively stratifying high-risk versus low-risk lesions. While new cyst fluid markers continue to be identified, additional efforts in testing panels and marker composites in conjunction with clinical algorithms have also shown promise in distinguishing dysplasia and the risk of malignancy. These should be tested prospectively in order to determine their role in guiding the surveillance of low-risk lesions and to evaluate the new markers detected by proteomics and genetic sequencing.

A new combined criterion to better predict malignant lesions in patients with pancreatic cystic neoplasms

Objective:

Cystic lesions of the pancreas have been increasingly recognized. Some lesions exhibit benign behavior, while others have unequivocal malignant potential. Thus, accurate identification of malignancy in patients diagnosed with pancreatic cystic neoplasms (PCNs) remains a major challenge. The aim of this study was to define a combined criterion to better predict malignant lesions in patients with PCNs.

Methods:

We retrospectively analyzed 165 patients who underwent resection of PCNs from October 2011 to May 2017. The relationship among malignancy and serum carbohydrate antigen 19-9 (CA19-9), preoperative neutrophil-to-lymphocyte ratio (NLR), and the presence of enhanced solid component on imaging was analyzed.

Results:

NLR before surgery in patients with malignant PCNs (2.81±2.14) was significantly higher than that in patients diagnosed with pancreatic neuroendocrine tumor (1.90±0.69, P=0.013) or healthy volunteers (1.40±0.48; P<0.001). Serum CA19-9 ≥39 U/mL, NLR >1.976 and presence of enhanced solid component were independent predictors of PCN malignancy. A combined criterion meeting any two or more of the three elements including CA19-9 ≥39 U/mL, NLR >1.976, and presence of enhanced solid component on computed tomography imaging is an indicator with a high positive predictive value of 80.5% and a high negative predictive value of 87.9%, and thus, represents a highly accurate test (86.1%).

Conclusions:

The new combined criterion is an effective predictor of tumor malignancy in patients with PCNs.

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.