Progression Of Intraductal Papillary Mucinous Neoplasms Research Articles

Abstract B037: Disks large-associated protein 5 (DLGAP5) is a putative prognostic biomarker for intraductal papillary mucinous neoplasm (IPMN) of pancreas

Abstract Pancreatic cancer is one of the deadliest malignant diseases, accounting for nearly 500,000 deaths worldwide each year. One of the pancreatic cancer precursors are mucinous pancreatic cystic lesions (PCL). Although only a minority of these PCLs undergo malignant transformation, the clinical significance is considerable, particularly given the prevalence of up to 45% in individuals over the age of 65. The most prevalent type of neoplastic PCL is intraductal papillary mucinous neoplasm (IPMN) and the management of different IPMN grades varies, with high- grade dysplasia and invasive carcinoma being indicated for surgery. However, the current guidelines for patient stratification are limited and often lead to either overtreatment or undertreatment, both of which are associated with high mortality and morbidity. Therefore, there is a pressing need to identify biomarkers associated with progression of IPMN from low to high grade that can be used for more accurate lesion assessment. Here we identified a novel biomarker highly correlated with IPMN progression – DLGAP5. Both mRNA as well as protein expression of DLGAP5 is positively associated with increased grade of IPMNs as determined by analysis of patient derived tumor samples. Additionally, in vitro experiments confirmed that knock down of DLGAP5 in pancreatic cancer cells leads to reduction of cell proliferation, and conversely, overexpression of DLGAP5 in IPMN precursor cells resulted in increased proliferation. Since one of the functions of DLGAP5 is microtubule stabilization, we hypothesized that the secretome of IPMN precursor cells will be altered by the expression of DLGAP5. Indeed, our mass spectrometry-based analysis of secreted proteins identified several hits (e.g. DKK1) that were correlated with DLGAP5 expression and were previously confirmed to be present in IPMN cyst fluid in patients. Subsequently, we aim to validate the correlation of the putative biomarkers in IPMN cyst fluid and serum with IPMN grade and patients’ clinical outcome in a prospective manner. To sum up, we validated DLGAP5 as an IPMN-progression biomarker and identified several secreted proteins that could serve as DLGAP5-surrogate biomarkers for stratification of the patients with IPMN and subsequent treatment optimalization. Citation Format: Radoslav Janostiak, Peter Mačinga, Lucia Csergeová, Ondřej Fabián, Eva Sticová, Jiří Zahradník, Martin Květoň, Tomáš Hucl. Disks large-associated protein 5 (DLGAP5) is a putative prognostic biomarker for intraductal papillary mucinous neoplasm (IPMN) of pancreas [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr B037.

Progression of Intraductal Papillary Mucinous Neoplasms of the Pancreas After Liver Transplantation.

Intraductal papillary mucinous neoplasms (IPMNs) are the most commonly identified pancreatic cystic neoplasms. Incidentally detected IPMNs are common among liver transplant recipients. The risk of IPMN progression to pancreatic cancer in transplant recipients and the impact of immunosuppression on the risk of malignant transformation of IPMN are unclear. In this retrospective study of consecutive liver transplant recipients across Mayo Clinic over a 13-year period, patients were assessed for possible IPMN by automated chart review. Pancreatic cystic lesions were characterized as suspected IPMNs based on imaging criteria. Cox proportional hazards models were used to determine the association between IPMN progression (the development of cancer or worrisome features) and clinical and immunosuppression regimen characteristics. Of 146 patients with suspected IPMNs, progression occurred in 7 patients (2 cases of IPMN-associated cancer and 5 cases of worrisome features) over an average follow-up of 66.6 months. Immunosuppression type, medication number, and tacrolimus trough levels were not associated with IPMN progression (p >0.05). Combined kidney and liver transplantation (p=0.005) and pretransplant cholangiocarcinoma (p=0.012) were associated with IPMN progression. IPMN progression is rare after liver transplantation even over an extended follow-up period. The findings were notable for the absence of an association between IPMN progression and immunosuppression regimen. Larger studies are needed given the low incidence.

Abstract PR-18: RNF43 Loss Induces an IRE1-dependent Metabolic Reprogramming in Pancreatic Cystic Neoplasms

Abstract Background: RNF43 is frequently mutated in intraductal papillary mucinous neoplasms (IPMNs), which are cystic precursor lesions of pancreatic ductal adenocarcinoma (PDAC). RNF43 encodes for an E3 ubiquitin ligase and was initially identified as a negative regulator of Wnt signaling in colorectal cancer. Clinical trials targeting ligand dependent Wnt signaling in RNF43-mutated cancers have failed to demonstrate any efficacy, suggesting other mechanisms may be involved. Methods: To elucidate the role of RNF43 in an organ specific context, we generated a genetically engineered mouse model with pancreas-specific loss of Rnf43 and co-expression of mutant Kras (referred to as Kras;Rnf43 mice). The Kras;Rnf43 mice develop pancreatic cystic lesions resembling human IPMNs, a subset of which progressive to invasive cancers. We generated derivative cell lines from the IPMN-associated cancers, referred to as Kras;Rnf43 lines. Single-cell RNA sequencing (scRNA-seq) was performed to compare murine PDAC arising in Kras;Rnf43 mice with that of the Kras;p53 (“KPC”) mice. To determine if observed perturbations were dependent on Rnf43, we also created isogenic Kras;Rnf43 cell lines with re-expression of full-length Rnf43 (Kras;Rnf43-RNF43OE). Results: Kras;Rnf43 tumors showed upregulation of several mitochondrial transcripts (Mt-Atp8, Atp5o.1, and Atp6v0c), as well as mitochondrial biogenesis markers (PPARGC1A and NFE2L2), compared to KPC mice. Concurrently, the oxidative phosphorylation (OXPHOS) pathway was enriched on proteomics analyses of Kras;Rnf43 cells, relative to isogenic cell lines with RNF43 restitution. Seahorse metabolic flux analyzer revealed enhanced mitochondrial OXPHOS activity in Kras;Rnf43 cell lines, along with increased mitophagy. Kras;Rnf43 cells harbored gene signatures indicative of endoplasmic reticulum (ER) stress compared to KPC lines. Endoplasmic reticulum-mitochondria contact sites (ERMCS) regulate ER stress and mitochondrial dynamics. Notably, Kras;Rnf43 cells had significantly increased ERMCS compared to KPC cells, and these were attenuated upon RNF43 re-expression. We further identified the ER stress sensor inositol-requiring protein 1 (IRE1) was markedly elevated in Kras;Rnf43 cells compared to KPC cells, and decreased upon RNF43 re-expression. Furthermore, IRE1 localized at the mitochondrial-associated membrane (MAM) and enhanced ERMCS formation via a non-canonical scaffolding function. Deletion of IRE1 by CRISPR/Cas9 editing in Kras;Rnf43 cells inhibited OXPHOS and significantly impaired cell viability. Conclusion: Our data suggests that bi-allelic loss of RNF43 caused increased mitochondrial function and OXPHOS dependency. This is largely attributed to upregulated level of IRE1, which localizes at MAM to promote ERMCS formation and OXPHOS in Kras;Rnf43 cells. IRE1-dependent reprogramming of mitochondrial bioenergetics serves as a cell survival mechanism. Therefore, targeting OXPHOS or the noncanonical function of IRE1 could be a potential strategy to inhibit the progression of RNF43-mutated IPMNs to PDAC. Citation Format: Akiko Sagara, Xiangdong Lv, Brandon Chen, Yuki Makino, Shui Ping So, Sonja M Woermann, Costas A Lyssiotis, Yatrik M Shah, Bidyut Ghosh, Xi Chen, Johannes F Fahrmann, Anirban Maitra. RNF43 Loss Induces an IRE1-dependent Metabolic Reprogramming in Pancreatic Cystic Neoplasms [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-18.

Abstract B091: Spatial Transcriptomics Unveils Intraductal Papillary Mucinous Neoplasm Heterogeneity: From Novel Clusters to Immune Dynamics

Abstract Intraductal papillary mucinous neoplasms (IPMNs), a common precursor to pancreatic ductal adenocarcinoma, present as a spectrum of benign indolent behavior and progression to invasive carcinoma, which highlights the importance of identifying biomarkers of IPMN progression. This study utilized whole transcriptome spatial transcriptomics to define the molecular characteristics of Epithelial, Immune, and Fibroblast cell populations of the three distinct histological sub-types of IPMN to understand the dynamics between the cell types and identify biomarkers of neoplastic progression. Fifty-two surgically resected IPMN cores from 21 patients with resected IPMNs comprising 24 Gastric, 14 Intestinal, and 14 Pancreaticobiliary with a distribution of low-grade dysplasia (LGD), high-grade dysplasia (HGD), and Invasive carcinoma (IC) were analyzed. Epithelial, Immune, and Fibroblast components were analyzed using the GeoMx spatial profiler. Unsupervised hierarchical clustering of epithelial areas of interest (AOI) identified 3 distinct clusters demonstrating a spectrum of molecular phenotypes in IPMN that were correlated with the three histological subtypes. Comparing the gene expression profile based on the shared genes expressed on all three subtypes, the Intestinal type tends to have an overexpression of genes whereas the Pancreaticobiliary represents a repressed phenotype relative to the Gastric phenotype. Supervised clustering using Moffitt’s classifier to identify the Epithelial-Mesenchymal transition demonstrates the Pancreaticobiliary subtype to be more Basal-like versus the Gastric and Intestinal inclined towards the classical phenotype. Supervised clustering based on the degree of dysplasia within the epithelial compartments of each of these subtypes, demonstrated a spectrum of molecular heterogeneity and identified biomarkers specific to High-Grade dysplasia in the Gastric and Intestinal subtype. Immune AOI deconvolution analysis demonstrated that Tregs were associated with Pancreaticobiliary, Macrophage enrichment associated with the Intestinal phenotype, while there is enrichment of CD8 T-cell and CD4 T-cell gene signatures associated with the Gastric subtype. Fibroblast AOI analyses demonstrated heterogenous myCAF- iCAF signatures between the subtypes. In summary, Spatial whole transcriptome analysis of IPMN identifies molecular signatures in epithelial and immune compartments that differentiate between the three histological subtypes of IPMN and helps understand their progression from Low-grade dysplasia to High-grade dysplasia. Citation Format: Amaya Pankaj, Michael J Raabe, Yuhui Song, Bidish K Patel, Katherine Xu, Joshua R Kocher, Nicholas J Caldwell, Maria L Ganci, Linda T Nieman, Mari Mino-Kenudson, Vikram Deshpande, Nabeel Bardeesy, Carlos Fernandez-Del Castillo, Martin J Aryee, David T Ting, Yasmin G Hernandez-Barco. Spatial Transcriptomics Unveils Intraductal Papillary Mucinous Neoplasm Heterogeneity: From Novel Clusters to Immune Dynamics [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B091.

Utility of Radiological Follow Up of Main-Duct Intraductal Papillary Mucinous Neoplasms and Mixed-Type Intraductal Papillary Mucinous Neoplasms.

Intraductal papillary mucinous neoplasms (IPMNs) have the potential to evolve into pancreatic adenocarcinoma (PDAC). While main-duct IPMNs (MD-IPMNs), involving the main pancreatic duct (MPD), are less common than side-branch IPMNs (SB-IPMNs) or mixed-type IPMNs (mixed-IPMNs), their malignant transformation potential is far greater. Controversy exists between different guidelines in terms of recommended management strategies. This study was aimed at assessing the utility of the radiological follow up of MD-IPMNs and mixed-type IPMNs, including prevalence of worrisome radiological findings as well as clinical and laboratory parameters, and their correlation with the development of progression or pancreatic adenocarcinoma. Eighty-four patients with MD-IPMNs or mixed-type IPMNs who underwent at least one magnetic resonance cholangiopancreatography (MRCP) were included. Clinical and laboratory data were obtained retrospectively. A cross-sectional analysis was carried out to establish clinical and laboratory parameters associated with development of PDAC. A retrospective cohort analysis was performed on 44 patients who had at least six months of follow up, trying to identify factors correlating with worrisome radiological features. Nine cases (10.7%) of PDAC were recorded in this cohort. The laboratory and imaging factors associated with cyst size progression greater than 5 mm during follow up were elevated alanine transaminase (ALT) levels, the maximal cyst size, and the MPD diameter. Cross-sectional analysis indicated that PDAC was associated with nausea (p = 0.01), as well as increased levels of aspartate aminotransferase (AST) (p = 0.05), gamma glutamyl transpeptidase (GGT) (p = 0.01), and alkaline phosphatase (ALP) (p = 0.01). Elevated levels of liver enzymes were associated with IPMN progression and, subsequently, the development of PDAC. ALT levels, maximal cyst size, and MPD diameter are associated with the progression of cyst size. These data may aid in risk-stratifying patients when determining the follow up approach for IPMNs.

Association of Smoking with progression from low-risk to high-risk intraductal papillary mucinous neoplasms and pancreatic cancer

BackgroundFactors associated with the risk of pancreatic adenocarcinoma (PDAC) may play a role in the development and progression of Intraductal Papillary Mucinous Neoplasms (IPMNs). However, data are limited. AimTo compare exposome factors in three groups of patients with “high or low-risk” IPMNs, as assessed at diagnosis and during a 24-months follow-up, and with PDAC. MethodsPatients were matched (same sex, age ±5) 1:1. Exposure variables were compared across groups using Kruskal-Wallis, ANOVA, or Chi-square tests with Bonferroni correction. ResultsA total of 151 patients were enrolled in each of the three groups (453 overall). The proportion of current smokers was progressively higher in “low-risk”, “high-risk” IPMNs and PDAC patients (8.1 %, 11.2 %, 23.3 %; p = 0.0002). The three groups did not differ in terms of ever or heavy smoking, BMI, history of diabetes, cancer, cholecystectomy or chronic pancreatitis, use of statins or aspirin, and family history of cancer. A history of peptic ulcer was more common in PDAC (7.2 %) than in either “low-risk” (2.0 %) or “high-risk” (2.6%) IPMNs (p = 0.02, not significant after Bonferroni correction). ConclusionActive smoking seems associated with the progression of IPMNs to malignancy, and cessation of active smoking might be advised in patients with IPMN.

Identification of spatially-resolved markers of malignant transformation in Intraductal Papillary Mucinous Neoplasms

The existing Intraductal Papillary Mucinous Neoplasm (IPMN) risk stratification relies on clinical and histological factors, resulting in inaccuracies and leading to suboptimal treatment. This is due to the lack of appropriate molecular markers that can guide patients toward the best therapeutic options. Here, we assess and confirm subtype-specific markers for IPMN across two independent cohorts of patients using two Spatial Transcriptomics (ST) technologies. Specifically, we identify HOXB3 and ZNF117 as markers for Low-Grade Dysplasia, SPDEF and gastric neck cell markers in borderline cases, and NKX6-2 and gastric isthmus cell markers in High-Grade-Dysplasia Gastric IPMN, highlighting the role of TNFα and MYC activation in IPMN progression and the role of NKX6-2 in the specific Gastric IPMN progression. In conclusion, our work provides a step forward in understanding the gene expression landscapes of IPMN and the critical transcriptional networks related to PDAC progression.

Single-cell RNA sequencing highlights epithelial and microenvironmental heterogeneity in malignant progression of pancreatic ductal adenocarcinoma

Intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are bona fide precursor lesions of pancreatic ductal adenocarcinoma (PDAC). Single-cell transcriptomics provides a unique perspective for dissecting the epithelial and microenvironmental heterogeneity that accompanies progression from benign IPMNs to invasive PDAC. Single-cell RNA sequencing was performed through droplet-based sequencing on 35 693 cells from three high-grade IPMNs and two IPMN-derived PDACs (all surgically resected). Analysis of single-cell transcriptomes revealed heterogeneous alterations within the epithelium and the tumor microenvironment during the progression of noninvasive dysplasia to invasive cancer. For epithelial cells, we identified acinar–ductal cells and isthmus–pit cells enriched in IPMN lesions and profiled three types of PDAC-unique ductal cells. Notably, a proinflammatory immune component was distinctly observed in IPMNs, comprising CD4+ T cells, CD8+ T cells, and B cells, whereas M2 macrophages were significantly accumulated in PDAC. Through the analysis of cellular communication, the osteopontin gene (SPP1)–CD44 pathway between macrophages and epithelial cells were particularly strengthened in the PDAC group. Further prognostic analysis revealed that SPP1 is a biomarker of IPMN carcinogenesis for surveillance. This study demonstrates the ability to perform high-resolution profiling of single cellular transcriptomes during the progression of high-grade IPMNs to cancer. Notably, single-cell analysis provides an unparalleled insight into both epithelial and microenvironmental heterogeneity associated with early cancer pathogenesis and provides practical markers for surveillance and targets for cancer interception.

Risk Assessment and Radiomics Analysis in Magnetic Resonance Imaging of Pancreatic Intraductal Papillary Mucinous Neoplasms (IPMN).

Intraductal papillary mucinous neoplasms (IPMNs) are a very common incidental finding during patient radiological assessment. These lesions may progress from low-grade dysplasia (LGD) to high-grade dysplasia (HGD) and even pancreatic cancer. The IPMN progression risk grows with time, so discontinuation of surveillance is not recommended. It is very important to identify imaging features that suggest LGD of IPMNs, and thus, distinguish lesions that only require careful surveillance from those that need surgical resection. It is important to know the management guidelines and especially the indications for surgery, to be able to point out in the report the findings that suggest malignant degeneration. The imaging tools employed for diagnosis and risk assessment are Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) with contrast medium. According to the latest European guidelines, MRI is the method of choice for the diagnosis and follow-up of patients with IPMN since this tool has a highest sensitivity in detecting mural nodules and intra-cystic septa. It plays a key role in the diagnosis of worrisome features and high-risk stigmata, which are associated with IPMNs malignant degeneration. Nowadays, the main limit of diagnostic tools is the ability to identify the precursor of pancreatic cancer. In this context, increasing attention is being given to artificial intelligence (AI) and radiomics analysis. However, these tools remain in an exploratory phase, considering the limitations of currently published studies. Key limits include noncompliance with AI best practices, radiomics workflow standardization, and clear reporting of study methodology, including segmentation and data balancing. In the radiological report it is useful to note the type of IPMN so as the morphological features, size, rate growth, wall, septa and mural nodules, on which the indications for surveillance and surgery are based. These features should be reported so as the surveillance time should be suggested according to guidelines.

Role of pancreatic ductal adenocarcinoma risk factors in intraductal papillary mucinous neoplasms progression.

Role of pancreatic ductal adenocarcinoma risk factors in intraductal papillary mucinous neoplasms progression.

Integrated Molecular Characterization of Intraductal Papillary Mucinous Neoplasms: An NCI Cancer Moonshot Precancer Atlas Pilot Project.

Integrated molecular analysis of genomic and transcriptomic alterations in the multistep progression of IPMNs, which are bona fide precursors of pancreatic cancer, identifies features associated with progression of low-risk lesions to high-risk lesions and cancer, which might enable patient stratification and cancer interception strategies.

Role of pancreatic ductal adenocarcinoma risk factors in intraductal papillary mucinous neoplasm progression.

Pancreatic ductal adenocarcinoma (PDAC) is lethal due to its late diagnosis and lack of successful treatments. A possible strategy to reduce its death burden is prevention. Intraductal papillary mucinous neoplasms (IPMNs) are precursors of PDAC. It is difficult to estimate the incidence of IPMNs because they are asymptomatic. Two recent studies reported pancreatic cysts in 3% and 13% of scanned subjects. The possibility of identifying a subgroup of IPMN patients with a higher probability of progression into cancer could be instrumental in increasing the survival rate. In this study, genetic and non-genetic PDAC risk factors were tested in a group of IPMN patients under surveillance. A retrospective study was conducted on 354 IPMN patients enrolled in two Italian centres with an average follow-up of 64 months. With the use of DNA extracted from blood, collected at IPMN diagnosis, all patients were genotyped for 30 known PDAC risk loci. The polymorphisms were analysed individually and grouped in an unweighted polygenic score (PGS) in relation to IPMN progression. The ABO blood group and non-genetic PDAC risk factors were also analysed. IPMN progression was defined based on the development of worrisome features and/or high-risk stigmata during follow-up. Two genetic variants (rs1517037 and rs10094872) showed suggestive associations with an increment of IPMN progression. After correction for multiple testing, using the Bonferroni correction, none of the variants showed a statistically significant association. However, associations were observed for the non-genetic variables, such as smoking status, comparing heavy smokers with light smokers (HR = 3.81, 95% 1.43-10.09, p = 0.007), and obesity (HR = 2.46, 95% CI 1.22-4.95, p = 0.012). In conclusion, this study is the first attempt to investigate the presence of shared genetic background between PDAC risk and IPMN progression; however, the results suggest that the 30 established PDAC susceptibility polymorphisms are not associated with clinical IPMN progression in a sample of 354 patients. However, we observed indications of cigarette smoking and body mass index (BMI) involvement in IPMN progression. The biological mechanism that could link these two risk factors to progression could be chronic inflammation, of which both smoking and obesity are strong promoters.

Risk Factors for Progression in Patients Undergoing Surveillance for Pancreatic Cysts.

To identify risk factors associated with the progression of pancreatic cysts in patients undergoing surveillance. Previous studies of intraductal papillary mucinous neoplasms (IPMNs) rely on surgical series to determine malignancy risk and have inconsistently identified characteristics associated with IPMN progression. We conducted a retrospective review of 2197 patients presenting with imaging concerning for IPMN from 2010 to 2019 at a single institution. Cyst progression was defined as resection or pancreatic cancer development. The median follow-up time was 84 months from the presentation. The median age was 66 years, and 62% were female. Ten percent had a first-degree relative with pancreatic cancer, and 3.2% had a germline mutation or genetic syndrome associated with an increased risk of pancreatic ductal adenocarcinoma (PDAC). Cumulative incidence of progression was 17.8% and 20.0% at 12 and 60 months postpresentation, respectively. Surgical pathology for 417 resected cases showed noninvasive IPMN in 39% of cases and PDAC with or without associated IPMN in 20%. Only 18 patients developed PDAC after 6 months of surveillance (0.8%). On multivariable analysis, symptomatic disease [hazard ratio (HR)=1.58; 95% CI: 1.25-2.01], current smoker status (HR=1.58; 95% CI: 1.16-2.15), cyst size (HR=1.26; 95% CI: 1.20-1.33), main duct dilation (HR=3.17; 95% CI: 2.44-4.11), and solid components (HR=1.89; 95% CI: 1.34-2.66) were associated with progression. Worrisome features on imaging at presentation, current smoker status, and symptomatic presentation are associated with IPMN progression. Most patients progressed within the first year of presentation to Memorial Sloan Kettering Cancer Center (MSKCC). Further investigation is necessary to develop personalized cyst surveillance strategies.

Artificial Intelligence in the Diagnosis and Treatment of Pancreatic Cystic Lesions and Adenocarcinoma.

Pancreatic cancer is projected to become the second leading cause of cancer-related mortality in the United States by 2030. This is in part due to the paucity of reliable screening and diagnostic options for early detection. Amongst known pre-malignant pancreatic lesions, pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs) are the most prevalent. The current standard of care for the diagnosis and classification of pancreatic cystic lesions (PCLs) involves cross-sectional imaging studies and endoscopic ultrasound (EUS) and, when indicated, EUS-guided fine needle aspiration and cyst fluid analysis. However, this is suboptimal for the identification and risk stratification of PCLs, with accuracy of only 65-75% for detecting mucinous PCLs. Artificial intelligence (AI) is a promising tool that has been applied to improve accuracy in screening for solid tumors, including breast, lung, cervical, and colon cancer. More recently, it has shown promise in diagnosing pancreatic cancer by identifying high-risk populations, risk-stratifying premalignant lesions, and predicting the progression of IPMNs to adenocarcinoma. This review summarizes the available literature on artificial intelligence in the screening and prognostication of precancerous lesions in the pancreas, and streamlining the diagnosis of pancreatic cancer.

The Role of Genetic, Metabolic, Inflammatory, and Immunologic Mediators in the Progression of Intraductal Papillary Mucinous Neoplasms to Pancreatic Adenocarcinoma.

Intraductal papillary mucinous neoplasms (IPMN) have the potential to progress to pancreatic ductal adenocarcinoma (PDAC). As with any progression to malignancy, there are a variety of genetic and metabolic changes, as well as other disruptions to the cellular microenvironment including immune alterations and inflammation, that can contribute to tumorigenesis. Previous studies further characterized these alterations, revealing changes in lipid and glucose metabolism, and signaling pathways that mediate the progression of IPMN to PDAC. With the increased diagnosis of IPMNs and pancreatic cysts on imaging, the opportunity to attenuate risk with the removal of high-risk lesions is possible with the understanding of what factors accelerate malignant progression and how they can be clinically utilized to determine the level of dysplasia and stratify the risk of progression. Here, we reviewed the genetic, metabolic, inflammatory, and immunologic pathways regulating the progression of IPMN to PDAC.

Abstract B058: The lincRNA Neat1 controls SWI/SNF occupancy to retain ductal cell identity in the pancreas

Abstract Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer deaths in the US and among the most fatal. Cancer originating from the ductal compartment often leads to the emergence of the highly aggressive basal subtype of PDAC. Defining the cellular and molecular origins of basal subtype PDAC would greatly improve our ability to devise strategies to treat patients with this aggressive form of PDAC. Towards this end, we have discovered that loss of the long intergenic non-coding RNA (lincRNA) Neat1 promotes ductal cell plasticity, dramatically inducing the formation of duct-derived preneoplastic lesions known as intraductal papillary mucinous neoplasms (IPMNs), and increasing the likelihood of basal subtype PDAC. Neat1 deficiency has a profound impact on chromatin organization and on the distribution of the SWI/SNF chromatin remodeling complex at the chromatin, suggesting that Neat1 maintains ductal cell identity via impacting SWI/SNF function. Probing for Brg1, a core component of the SWI/SNF complex, we demonstrated that Neat1 loss leads to decreased SWI/SNF binding at enhancer regions. This idea is further supported by the phenotypic similarities between mice deficient for Neat1 and Arid1a. We thus hypothesize that Neat1 and SWI/SNF are critical for the maintenance of ductal cell identity in the pancreas via controlling SWI/SNF-dependent enhancer activity and that loss of Neat1 increases ductal cell transformation and thus facilitates IPMN formation and progression to basal subtype PDAC. These studies will reveal both the biological role and mechanistic underpinnings of the lincRNA Neat1 in relationship with the SWI/SNF chromatin remodeling complexes. Our data suggest that Neat1 or SWI/SNF loss-of-function predisposes pancreatic ductal cells towards the most aggressive subtype of PDAC, laying critical groundwork for development of new diagnostic tools and therapeutic targets. Citation Format: Emily Berry, Zamira Guerra Soares, Jennifer Twardowski, Wenjia Wang, Aram Hezel, Stephano S. Mello. The lincRNA Neat1 controls SWI/SNF occupancy to retain ductal cell identity in the pancreas [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr B058.

Mechanisms of development and progression of pancreatic neoplasms.

Pancreatic ductal adenocarcinoma (PDAC) develops via dysplastic changes in the epithelia graded as low- and high-grade with accumulation of molecular alterations. Constitutive activation of mitogen-activated protein kinase (MAPK) contributed by attenuation of DUSP6 plays a key role in sustaining PDAC. Active MAPK induces various molecules that function as effectors to sustain PDAC. AURKA and SON are downstream effectors that contribute substantially to the proliferation and survival of PDAC cells and are potentially useful as therapeutic targets. Active MAPK also promote microRNAs that modulate the proliferation of PDAC cells and are useful as diagnostic markers. Familial pancreatic cancer kindreds in Japan show various germline mutations supposed to increase a pancreatic cancer risk. Intraductal papillary mucinous neoplasms (IPMNs) consist of dilated ducts lined by papillary neoplastic epithelia of various shapes and varying grades of atypia. Various papillae of IPMNs are classified into four subtypes that are associated with clinicopathological features, including patient prognosis. GNAS is a specific driver gene for the development of IPMN through gain-of-function mutations. Tracing of molecular alterations has elucidated the mechanism of progression of IPMN from dysplasia to carcinoma, as well as one type of papillae. Intraductal tubulopapillary neoplasms belong to a distinct class of pancreatic neoplasms.

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.

Peak density of immature nerve cells occurs with high-grade dysplasia in intraductal papillary mucinous neoplasms of the pancreas.

The development of neural structures within tumors is now considered vital for carcinogenesis. However, the time course of this development in human pre-invasive neoplasia has been incompletely described. Therefore, we performed a detailed analysis of nerves across the neoplastic spectrum in resected intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. Histology and multiplexed immunochemistry demonstrated that nerve density increased from low-grade (LG) to high-grade dysplasia (HG) but did not further increase once invasive IPMN (INV IPMN) was present. Higher nerve density correlated with increasing expression of nerve growth factor (NGF) by the tumor cells. Intra-tumoral nerves were immature and lacked markers of sympathetic, parasympathetic, and sensory lineages. Here, we show for the first time the presence of neural precursor cells (NPCs) within the stroma of pancreatic tumors. The density of these doublecortin (DCX)-positive NPCs increased from LG to HG, but not from HG to INV IPMN. We conclude that peak neural density of tumors is reached in high-grade dysplasia (often termed carcinoma in situ) rather than after invasion. These findings suggest that nerve-tumor interactions are important in IPMN progression and may serve as the basis for future mechanistic studies and novel therapeutic modalities. © 2022 The Pathological Society of Great Britain and Ireland.

Association Between Clinical Backgrounds and Malignant Progression of Suspected Intraductal Papillary Mucinous Neoplasm.

Some intraductal papillary mucinous neoplasms (IPMNs) have malignant potential and can become pancreatic cancer. The mechanism behind the malignant progression of IPMN remains unknown. We aimed to identify the risk factors and interactions between backgrounds for IPMN. We retrospectively enrolled 980 patients of pancreatic cancer or suspected IPMN (sIPMN) who underwent endoscopic ultrasound or retrograde cholangiopancreatography. We classified them into pancreatic cancer, high-risk sIPMN, and low-risk sIPMN, and investigated the risk factors for high-risk sIPMN. Smoking habits (odds ratio [OR], 3.74; 95% confidence interval [CI], 2.04-6.85; P < 0.001), serum carbohydrate antigen 19-9 ≥37 U/mL (OR, 6.30; 95% CI, 2.88-13.80; P < 0.001), and family history of cancers (OR, 2.38; 95% CI, 1.30-4.37; P = 0.005) were independent risk factors for high-risk suspected IPMN. Odds ratios of diabetes and neutrophil-to-lymphocyte ratio of 2.45 or greater were significantly higher in patients with a family history of cancer than those without a family history of cancer (OR, 3.28; 95% CI, 0.52-20.80 vs 1.85; 95% CI, 0.78-4.41; OR, 2.44; 95% CI, 0.81-7.34 vs 1.24; 95% CI, 0.67-2.30, respectively). Understanding the interactions between background factors can effectively prevent IPMNs' malignant transformation.