Diversity of Precursor Lesions For Pancreatic Cancer: The Genetics and Biology of Intraductal Papillary Mucinous Neoplasm. Clin Transl Gastroenterol. 2017;8:e86. [PMID: 28383565 PMCID: PMC5415899 DOI: 10.1038/ctg.2017.3]

Enhancing noninvasive pancreatic cystic neoplasm diagnosis with multimodal machine learning

Pancreatic cystic neoplasms (PCNs) are a complex group of lesions with a spectrum of malignancy. Accurate differentiation of PCN types is crucial for patient management, as misdiagnosis can result in unnecessary surgeries or treatment delays, affecting the quality of life. The significance of developing a non-invasive, accurate diagnostic model is underscored by the need to improve patient outcomes and reduce the impact of these conditions. We developed a machine learning model capable of accurately identifying different types of PCNs in a non-invasive manner, by using a dataset comprising 449 MRI and 568 CT scans from adult patients, spanning from 2009 to 2022. The study's results indicate that our multimodal machine learning algorithm, which integrates both clinical and imaging data, significantly outperforms single-source data algorithms. Specifically, it demonstrated state-of-the-art performance in classifying PCN types, achieving an average accuracy of 91.2%, precision of 91.7%, sensitivity of 88.9%, and specificity of 96.5%. Remarkably, for patients with mucinous cystic neoplasms (MCNs), regardless of undergoing MRI or CT imaging, the model achieved a 100% prediction accuracy rate. It indicates that our non-invasive multimodal machine learning model offers strong support for the early screening of MCNs, and represents a significant advancement in PCN diagnosis for improving clinical practice and patient outcomes. We also achieved the best results on an additional pancreatic cancer dataset, which further proves the generality of our model.

Highly multiplexed digital PCR assay for simultaneous quantification of variant allele frequencies and copy number alterations of KRAS and GNAS in pancreatic cancer precursors

Pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMNs) are pancreatic ductal adenocarcinoma (PDAC) precursor lesions. Detecting these precursors and monitoring their progression are crucial for early PDAC diagnosis. Digital PCR (dPCR) is a highly sensitive nucleic acid quantification technique and offers a cost-effective option for patient follow-up. However, the clinical utility of conventional dPCR is restricted by multiplexing constraints, particularly due to the challenge of simultaneously quantifying multiple mutations and amplifications. In this study, we applied highly multiplexed dPCR and melting curve analysis to simultaneously measure single nucleotide mutations and amplifications of KRAS and GNAS. The developed 14-plex assay included both wild-type and mutant KRAS, a common driver gene in both PanIN and IPMN, and GNAS, which is specifically mutated in IPMN, along with RPP30, a reference gene for copy number alterations (CNAs). This multiplex dPCR method detected all target mutations with a limit of detection below 0.2% while quantifying CNAs. Additionally, the assay accurately quantified variant allele frequencies in liquid biopsy and tissue samples from both pancreatic neoplasm precursor and PDAC patients, indicating its potential for use in comprehensive patient follow-up.

Defining and Predicting Early Recurrence for Optimal Treatment Strategies for Intraductal Papillary Mucinous Neoplasm-Derived Pancreatic Cancer: An International Multicenter Study

BACKGROUND

Early recurrence in intraductal papillary mucinous neoplasm (IPMN)-derived pancreatic ductal adenocarcinoma (PDAC) is poorly defined. Predictors are lacking and needed for patient counseling, risk stratification, and postoperative management. This study aimed to define and predict early recurrence for patients in resected IPMN-derived PDAC and guide management.

METHODS

A lowest p value for survival after recurrence (SAR) was used to define early recurrence in resected IPMN-derived PDAC from five international centers. Overall survival (OS) and SAR were compared using log-rank tests. A multivariable logistic regression identified odds ratios (ORs) with 95 % confidence intervals (CIs) for early recurrence. Rounded ORs were used to stratify patients into low-, intermediate-, and high-risk groups using upper and lower quartile score distributions. Adjuvant chemotherapy was assessed by Cox regression and log-rank tests for OS in risk groups.

RESULTS

Recurrence developed in 160 (42 %) of 381 patients. Early recurrence was defined at 10.5 months and observed in 61 patients (38 % of recurrences). The median SAR for the patients with early recurrence was 8.3 months (95 % CI, 3.1-16.1 months) compared with 12.9 months (95 % CI, 5.2-27.5 months) for the patients with late recurrence. The independent predictors of early recurrence were CA19-9 (OR, 3.80; 95 % CI, 1.54-9.41) and N2 disease (OR, 7.29; 95 % CI, 3.22-16.49). The early recurrence rates in the low-, intermediate-, and high-risk groups were respectively 1 %, 14 %, and 32 %. Adjuvant chemotherapy was associated with improved OS only for the high-risk patients (hazard ratio, 0.50; 95 % CI, 0.32-0.79).

CONCLUSION

In IPMN-derived PDAC, the optimal cutoff for early recurrence is 10.5 months. Both CA19-9 and N stage predict early recurrence. Adjuvant chemotherapy is associated with survival benefit only for high-risk patients.

Cystic Fluid Total Proteins, Low-Density Lipoprotein Cholesterol, Lipid Metabolites, and Lymphocytes: Worrisome Biomarkers for Intraductal Papillary Mucinous Neoplasms

Objectives: Pancreatic cystic neoplasms (PCNs), particularly intraductal papillary mucinous neoplasms (IPMNs), present a challenge for their potential malignancy. Despite promising biomarkers like CEA, amylase, and glucose, our study investigates whether metabolic indices in blood and cystic fluids (CFs), in addition to lymphocyte subsets and hematopoietic stem/progenitor cells (HSPCs), can effectively differentiate between high- and low-risk PCNs. Materials and Methods: A total of 26 patients (11 males, mean age 69.5 ± 9 years) undergoing Endoscopic Ultrasound-guided Fine Needle Aspiration were consecutively enrolled. Analyses included blood, serum, and CF, assessing glucose, CEA, cholesterol (total, HDL, and LDL), and total proteins. Flow cytometry examined immunophenotyping in peripheral blood and cystic fluids. Mass spectrometry was used for the metabolomic analysis of CF. Sensitivity, specificity, and ROC analyses evaluated discriminatory power. Results: A total of 25 out of 26 patients had IPMN. Patients were categorized as low or high risk based on multidisciplinary evaluation of clinical, radiological, and endoscopic data. High-risk patients showed lower CF total proteins and LDL cholesterol (p = 0.005 and p = 0.031), with a marked reduction in CF lymphocytes (p = 0.005). HSCPs were absent in CF. In blood, high-risk patients showed increased non-MHC-restricted cytotoxic T cells (p = 0.019). The metabolomic analysis revealed significantly reduced middle and long-chain acyl carnitines (AcCa) and tryptophan metabolites in high-risk patients. ROC curves indicated comparable discriminant abilities for CF lymphocytes (AUC 0.868), CF total proteins (AUC 0.859), and CF LDL cholesterol (AUC 0.795). The highest performance was achieved by the AcCa 14:2 and 16:0 (AUC: 0.9221 and 0.8857, respectively). Conclusions: CF levels of glucose, CEA, LDL cholesterol, and total proteins together with lymphocyte counts are easy translational biomarkers that may support risk stratification of PCNs in IPMN patients and might be endorsed by metabolomic analysis. Further studies are required for potential clinical integration.

Older Age as a Worrisome Feature in Patients With Intraductal Papillary Mucinous Neoplasms: A Long-Term Surveillance Study

INTRODUCTION

Aging has been implicated in the development of various cancer types. No study has specifically investigated age at intraductal papillary mucinous neoplasm (IPMN) diagnosis in relation to the long-term risk of pancreatic carcinogenesis.

METHODS

Within a prospective cohort of 4,104 patients diagnosed with pancreatic cysts, we identified 3,142 patients with IPMNs and examined an association of age at IPMN diagnosis with the incidence of pancreatic carcinoma. Using the multivariable competing-risks proportional hazards regression model, we estimated subdistribution hazard ratios (SHRs) and 95% confidence intervals (CIs) for pancreatic carcinoma incidence according to age at IPMN diagnosis.

RESULTS

During 22,187 person-years of follow-up, we documented 130 patients diagnosed with pancreatic carcinoma (64 with IPMN-derived carcinoma and 66 with concomitant ductal adenocarcinoma). Older age at IPMN diagnosis was associated with a higher risk of pancreatic cancer incidence ( Ptrend = 0.002). Compared with patients younger than 55 years, patients aged 55-64, 65-74, and ≥ 75 years had adjusted SHRs of 1.80 (95% CI, 0.75-4.32), 2.56 (95% CI, 1.10-5.98), and 3.31 (95% CI, 1.40-7.83), respectively. Patients aged 70 years and older had a numerically similar adjusted SHR compared with patients younger than 70 years with worrisome features defined by the international consensus guidelines (1.73 [95% CI, 1.01-2.97] and 1.66 [95% CI, 0.89-3.10], respectively).

DISCUSSION

Older patients with IPMNs were at a higher risk of developing pancreatic carcinoma during surveillance. Surgically fit elderly patients may be good candidates for periodic surveillance aimed at a reduction of pancreatic cancer-related deaths.

Risk factors for pancreatic cancer in individuals with intraductal papillary mucinous neoplasms and no high-risk stigmata during up to 5 years of surveillance: a prospective longitudinal cohort study

BACKGROUND

Cyst size, its growth rate, and diameter of the main pancreatic duct (MPD) are all associated with pancreatic carcinoma prevalence in intraductal papillary mucinous neoplasms (IPMNs).

OBJECTIVE

To examine the above factors in relation to future risk of incident pancreatic carcinoma in individuals with IPMNs harbouring no high-risk stigmata.

DESIGN

In a prospective longitudinal cohort, we analysed 2549 patients with IPMNs. A multivariable cause-specific Cox proportional hazards regression model was built to estimate HRs for incident pancreatic carcinoma.

RESULTS

IPMN size at baseline and its annual growth rate over 2 years of follow-up were associated with incident pancreatic carcinoma (ptrend<0.001). The multivariable cause-specific HR per 10 mm increase in IPMN size was 1.28 (95% CI 1.10 to 1.50). The annual growth rates of 1.5-2.4 mm/year and ≥2.5 mm/year over 2 years were associated with multivariable cause-specific HRs of 1.91 (95% CI 0.78 to 4.67) and 4.52 (95% CI 2.28 to 8.98), respectively (vs <1.5 mm/year). Neither IPMN size at 5 years nor its maximum growth rate during 5 years was associated with incident pancreatic carcinoma (ptrend>0.07). MPD diameter at 5 years was associated with incident pancreatic carcinoma (multivariable cause-specific HR per 2 mm increase, 2.12; 95% CI 1.72 to 2.63). A predictive nomogram was generated for calculating the risk of incident pancreatic carcinoma.

CONCLUSION

IPMN size and its growth rate predict future pancreatic carcinoma risk only during first 5 years of follow-up. MPD diameter at 5 years may identify patients who still harbour a high risk for pancreatic carcinoma.

The Revised Kyoto Criteria and Risk of Malignancy Among Patients With Intraductal Papillary Mucinous Neoplasms

BACKGROUND & AIMS

The revised Kyoto guidelines have a new catalog of high-risk stigmata and worrisome features for the risk stratification of intraductal papillary mucinous neoplasms (IPMNs). We aimed to validate the stratification system in terms of short- and long-term risks of pancreatic carcinoma.

METHODS

We included 3336 patients diagnosed with IPMNs in 2000-2021 and examined short-term (≤6 months) and long-term risks of pancreatic carcinoma diagnosis. We used the multivariable competing-risks proportional hazards regression model to calculate subdistribution hazard ratios for long-term incidence of pancreatic carcinoma with adjustment for potential confounders.

RESULTS

In short-term analyses, pancreatic carcinomas were prevalent predominantly in IPMNs with high-risk stigmata (49% vs 1.3% and 0.05% in IPMNs with worrisome features and no risk factors, respectively). In long-term analyses of worrisome features, the main pancreatic duct diameter of 5-9.9 mm, acute pancreatitis, and IPMN growth rate of 2.5 mm/y were associated with a high incidence with multivariable subdistribution hazard ratios of 3.46 (95% confidence interval [CI], 2.04-5.89), 5.65 (95% CI, 1.86-17.2), and 3.83 (95% CI, 2.14-6.86), respectively. An increasing number of worrisome features at baseline was associated with a higher prevalence and incidence of pancreatic carcinoma (Ptrend < .001). Patients with 1, 2, and 3-4 worrisome features had multivariable subdistribution hazard ratios for pancreatic cancer incidence of 1.43 (95% CI, 0.93-2.19), 2.17 (95% CI, 1.17-4.05), and 10.1 (95% CI, 4.20-24.5), respectively (vs no positive feature).

CONCLUSIONS

The revised Kyoto criteria stratify IPMN patients well in terms of the short- and long-term risks of pancreatic carcinoma diagnosis, potentially informing personalized patient management.

Outcomes in intraductal papillary mucinous neoplasm-derived pancreatic cancer differ from PanIN-derived pancreatic cancer

BACKGROUND AND AIM

Intraductal papillary mucinous neoplasm (IPMN)-derived pancreatic ductal adenocarcinoma (PDAC) management is generally extrapolated from pancreatic intraepithelial neoplasia (PanIN)-derived PDAC guidelines. However, these are biologically divergent, and heterogeneity further exists between tubular and colloid subtypes.

METHODS

Consecutive upfront surgery patients with PanIN-derived and IPMN-derived PDAC were retrospectively identified from international centers (2000-2019). One-to-one propensity score matching for clinicopathologic factors generated three cohorts: IPMN-derived versus PanIN-derived PDAC, tubular IPMN-derived versus PanIN-derived PDAC, and tubular versus colloid IPMN-derived PDAC. Overall survival (OS) was compared using Kaplan-Meier and log-rank tests. Multivariable Cox regression determined corresponding hazard ratios (HR) and 95% confidence intervals (95% CI).

RESULTS

The median OS (mOS) in 2350 PanIN-derived and 700 IPMN-derived PDAC patients was 23.0 and 43.1 months (P < 0.001), respectively. PanIN-derived PDAC had worse T-stage, CA19-9, grade, and nodal status. Tubular subtype had worse T-stage, CA19-9, grade, nodal status, and R1 margins, with a mOS of 33.7 versus 94.1 months (P < 0.001) in colloid. Matched (n = 495), PanIN-derived and IPMN-derived PDAC had mOSs of 30.6 and 42.8 months (P < 0.001), respectively. In matched (n = 341) PanIN-derived and tubular IPMN-derived PDAC, mOS remained poorer (27.7 vs 37.4, P < 0.001). Matched tubular and colloid cancers (n = 112) had similar OS (P = 0.55). On multivariable Cox regression, PanIN-derived PDAC was associated with worse OS than IPMN-derived (HR: 1.66, 95% CI: 1.44-1.90) and tubular IPMN-derived (HR: 1.53, 95% CI: 1.32-1.77) PDAC. Colloid and tubular subtype was not associated with OS (P = 0.16).

CONCLUSIONS

PanIN-derived PDAC has worse survival than IPMN-derived PDAC supporting distinct outcomes. Although more indolent, colloid IPMN-derived PDAC has similar survival to tubular after risk adjustment.

An international multi-institutional validation of T1 sub-staging of intraductal papillary mucinous neoplasm-derived pancreatic cancer

BACKGROUND

Intraductal papillary mucinous neoplasm (IPMN)-derived pancreatic ductal adenocarcinoma (PDAC) is resected at smaller sizes compared with its biologically distinct counterpart, pancreatic intraepithelial neoplasia (PanIN)-derived PDAC. Thus, experts proposed T1 sub-staging for IPMN-derived PDAC. However, this has never been validated.

METHODS

Consecutive upfront surgery patients with IPMN-derived PDAC from 5 international high-volume centers were classified by the proposed T1 sub-staging classification (T1a ≤0.5, T1b >0.5 and ≤1.0, and T1c >1.0 and ≤2.0 cm) using the invasive component size. Kaplan-Meier and log-rank tests were used to compare overall survival (OS). A multivariable Cox regression was used to determine hazard ratios (HRs) with confidence intervals (95% CIs).

RESULTS

Among 747 patients, 69 (9.2%), 50 (6.7%), 99 (13.0%), and 531 patients (71.1%), comprised the T1a, T1b, T1c, and T2-4 subgroups, respectively. Increasing T-stage was associated with elevated CA19-9, poorer grade, nodal positivity, R1 margin, and tubular subtype. Median OS for T1a, T1b, T1c, and T2-4 were 159.0 (95% CI = 126.0 to NR), 128.8 (98.3 to NR), 77.6 (48.3 to 108.2), and 31.4 (27.5 to 37.7) months, respectively (P < .001). OS decreased with increasing T-stage for all pairwise comparisons (all P < .05). After risk adjustment, older than age 65, elevated CA19-9, T1b [HR = 2.55 (1.22 to 5.32)], T1c [HR = 3.04 (1.60 to 5.76)], and T2-4 [HR = 3.41 (1.89 to 6.17)] compared with T1a, nodal positivity, R1 margin, and no adjuvant chemotherapy were associated with worse OS. Disease recurrence was more common in T2-4 tumors (56.4%) compared with T1a (18.2%), T1b (23.9%), and T1c (36.1%, P < .001).

CONCLUSION

T1 sub-staging of IPMN-derived PDAC is valid and has significant prognostic value. Advancing T1 sub-stage is associated with worse histopathology, survival, and recurrence. T1 sub-staging is recommended for future guidelines.

Clinical Perspectives on the Histomolecular Features of the Pancreatic Precursor Lesions: A Narrative Review

Pancreatic cancer (PC) is a lethal cancer with poor prognoses. Identifying and characterizing pancreatic cystic lesions (PCLs) in the early detection and follow-up plans is thought to help detect pancreatic malignancy. Besides, the molecular features of PCLs are thought to unravel potentials for targeted therapies. We present a narrative review of the existing literature on the role of PCLs in the early detection, risk stratification, and medical management of PC. High-grade intraductal papillary mucinous neoplasms (IPMN) and pancreatic intraepithelial neoplasia (PanIN) stage III are high-risk lesions for developing PC. These lesions often require thorough histomolecular characterization using endoscopic ultrasound (EUS), before a surgical decision is made. EUS is also useful in the risk assessment of PCLs with tentative plans-for instance, in branch-duct IPMNs (BD-IPMN)- where the final decision might change. Besides the operative decisions, recent improvements in the application of targeted therapies are expected to improve survival measures. Knowledge of molecular features has helped develop targeted therapies. In summary, the histomolecular characterization of PCLs is helpful in optimizing management plans in PC. Further improvements are still needed for the broad application of this knowledge in the clinical setting.

Ras-dependent activation of BMAL2 regulates hypoxic metabolism in pancreatic cancer

To identify drivers of malignancy in human pancreatic ductal adenocarcinoma (PDAC), we performed regulatory network analysis on a large collection of expression profiles from laser capture microdissected samples of PDAC and benign precursors. We discovered that BMAL2 plays a role in the initiation, progression, post resection survival, and KRAS activity in PDAC. Functional analysis of BMAL2 target genes led us to hypothesize that it plays a role in regulating the response to hypoxia, a critical but poorly understood feature of PDAC physiology. Knockout of BMAL2 in multiple human PDAC cell lines revealed effects on viability and invasion, particularly under hypoxic conditions. Loss of BMAL2 also affected glycolysis and other metabolic processes. We found that BMAL2 directly regulates hypoxia-responsive target genes. We also found that BMAL2 is necessary for the stabilization of HIF1A upon exposure to hypoxia, but destabilizes HIF2A under hypoxia. These data demonstrate that BMAL2 is a master transcriptional regulator of hypoxia responses in PDAC and may serve as a long-sought molecular switch that distinguishes HIF1A- and HIF2A-dependent modes of hypoxic metabolism.

Liquid Biopsy for Pancreatic Cancer by Serum Extracellular Vesicle-Encapsulated Long Noncoding RNA HEVEPA

OBJECTIVES

The role of long noncoding RNAs (lncRNAs) in pancreatic ductal adenocarcinoma (PDAC) remain unclear. Extracellular vesicle (EV)-encapsulated RNAs could be effective targets for liquid biopsy. We aimed to identify previously unknown EV-encapsulated lncRNAs in PDAC and establish highly accurate methods for isolating EVs.

MATERIALS AND METHODS

Extracellular vesicles were isolated using existing and newly developed methods, namely, PEViA-UC and PEViA-IP, from serum samples of 20 patients with PDAC, 22 patients with intraductal papillary mucinous neoplasms, and 21 healthy individuals. Extracellular vesicle lncRNA expression was analyzed using digital PCR.

RESULTS

Gene expression analysis using cDNA microarray revealed a highly expressed lncRNA, HEVEPA , in serum EVs from patients with PDAC. We established PEViA-UC and PEViA-IP using PEViA reagent, ultracentrifugation, and immunoprecipitation. Although detection of EV-encapsulated HEVEPA using existing methods is challenging, PEViA-UC and PEViA-IP detected EV HEVEPA , which was highly expressed in patients with PDAC compared with non-PDAC patients. The detection sensitivity for discriminating PDAC from non-PDAC using the combination of HEVEPA and HULC , which are highly expressed lncRNAs in PDAC, and carbohydrate antigen 19-9 (CA19-9), was higher than that of HEVEPA , HULC , or CA19-9 alone.

CONCLUSIONS

Extracellular vesicle lncRNAs isolated using PEViA-IP and CA19-9 together could be effective targets in liquid biopsy for PDAC diagnosis.

CT findings and clinical effects of high grade pancreatic intraepithelial neoplasia in patients with intraductal papillary mucinous neoplasms

PURPOSE

To investigate the common CT findings of high-grade (HG) PanIN and clinical effects in the remnant pancreas in patients with intraductal papillary mucinous neoplasm (IPMN) of the pancreas.

MATERIALS AND METHODS

Two hundred fifty-one patients with surgically confirmed IPMNs (118 malignant [invasive carcinoma/high-grade dysplasia] and 133 benign [low-grade dysplasia]) were retrospectively enrolled. The grade of PanIN (233 absent/low-grade and 18 high-grade) was recorded, and all patients underwent serial CT follow-up before and after surgery. Two radiologists analyzed CT findings of high-risk stigmata or worrisome features according to 2017 international consensus guidelines. They also analyzed tumor recurrence on serial follow-up CT after surgery. Statistical analyses were performed to identify significant predictors and clinical impact on postoperative outcomes of HG PanIN.

RESULTS

PanIN grade showed a significant association with IPMN grade (p = 0.012). Enhancing mural nodules ≥5 mm, abrupt main pancreatic duct (MPD) changes with distal pancreatic atrophy, increased mural nodule size and MPD diameter were common findings in HG PanIN (P<0.05). In multivariate analysis, abrupt MPD change with distal pancreatic atrophy (odds ratio (OR) 6.59, 95% CI: 2.32-18.72, <0.001) and mural nodule size (OR, 1.05; 95% CI, 1.02-1.08, 0.004) were important predictors for HG PanIN. During postoperative follow-up, HG PanIN (OR, 4.98; 95% CI, 1.22-20.33, 0.025) was significantly associated with cancer recurrence in the remnant pancreas.

CONCLUSION

CT can be useful for predicting HG PanIN using common features, such as abrupt MPD changes and mural nodules. In HG PanIN, extra caution is needed to monitor postoperative recurrence during follow-up.

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.

Radiomics model versus 2017 revised international consensus guidelines for predicting malignant intraductal papillary mucinous neoplasms

OBJECTIVES

To evaluate a CT-based radiomics model for identifying malignant pancreatic intraductal papillary mucinous neoplasms (IPMNs) and compare its performance with the 2017 international consensus guidelines (ICGs).

MATERIALS AND METHODS

We retrospectively included 194 consecutive patients who underwent surgical resection of pancreatic IPMNs between January 2008 and December 2020. Surgical histopathology was the reference standard for diagnosing malignancy. Using radiomics features from preoperative contrast-enhanced CT, a radiomics model was built with the least absolute shrinkage and selection operator by a five-fold cross-validation. CT and MR images were independently reviewed based on the 2017 ICGs by two abdominal radiologists, and the performances of the 2017 ICGs and radiomics model were compared. The areas under the curve (AUCs) were compared using the DeLong method.

RESULTS

A total of 194 patients with pancreatic IPMNs (benign, 83 [43%]; malignant, 111 [57%]) were chronologically divided into training (n = 141; age, 65 ± 8.6 years; 88 males) and validation sets (n = 53; age, 66 ± 9.7 years; 31 males). There was no statistically significant difference in the diagnostic performance of the 2017 ICGs between CT and MRI (AUC, 0.71 vs. 0.71; p = 0.93) with excellent intermodality agreement (k = 0.86). In the validation set, the CT radiomics model had higher AUC (0.85 vs. 0.71; p = 0.038), specificity (84.6% vs. 61.5%; p = 0.041), and positive predictive value (84.0% vs. 66.7%; p = 0.044) than the 2017 ICGs.

CONCLUSION

The CT radiomics model exhibited better diagnostic performance than the 2017 ICGs in classifying malignant IPMNs.

CLINICAL RELEVANCE STATEMENT

Compared with the radiologists' evaluation based on the 2017 international consensus guidelines, the CT radiomics model exhibited better diagnostic performance in classifying malignant intraductal papillary mucinous neoplasms.

KEY POINTS

• There is a paucity of comparisons between the 2017 international consensus guidelines (ICGs) and radiomics models for malignant intraductal papillary mucinous neoplasms (IPMNs). • The CT radiomics model developed in this study exhibited better diagnostic performance than the 2017 ICGs in classifying malignant IPMNs. • The radiomics model may serve as a valuable complementary tool to the 2017 ICGs, potentially allowing a more quantitative assessment of IPMNs.

Talniflumate abrogates mucin immune suppressive barrier improving efficacy of gemcitabine and nab-paclitaxel treatment in pancreatic cancer

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease. This is due to its aggressive course, late diagnosis and its intrinsic drugs resistance. The complexity of the tumor, in terms of cell components and heterogeneity, has led to the approval of few therapies with limited efficacy. The study of the early stages of carcinogenesis provides the opportunity for the identification of actionable pathways that underpin therapeutic resistance.

METHODS

We analyzed 43 Intraductal papillary mucinous neoplasms (IPMN) (12 Low-grade and 31 High-grade) by Spatial Transcriptomics. Mouse and human pancreatic cancer organoids and T cells interaction platforms were established to test the role of mucins expression on T cells activity. Syngeneic mouse model of PDAC was used to explore the impact of mucins downregulation on standard therapy efficacy.

RESULTS

Spatial transcriptomics showed that mucin O-glycosylation pathway is increased in the progression from low-grade to high-grade IPMN. We identified GCNT3, a master regulator of mucins expression, as an actionable target of this pathway by talniflumate. We showed that talniflumate impaired mucins expression increasing T cell activation and recognition using both mouse and human organoid interaction platforms. In vivo experiments showed that talniflumate was able to increase the efficacy of the chemotherapy by boosting immune infiltration.

CONCLUSIONS

Finally, we demonstrated that combination of talniflumate, an anti-inflammatory drug, with chemotherapy effectively improves anti-tumor effect in PDAC.

Co-occurring IPMN and pancreatic cancer: the same or different? An overview from histology to molecular pathology

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas is one of the most well-established precursors of pancreatic cancer. Its progression to acquire invasiveness is a complex process, based on the accumulation of morphological and genetic alterations. Recent advances in DNA sequencing also showed that co-occurring IPMNs and pancreatic cancers could be totally independent, further complicating our understanding of this complex scenario. The distinction between IPMN and related pancreatic cancer vs IPMN and co-occurring-but not related-pancreatic cancer is a challenging task in routine diagnostic activity, but may have important implications for precision oncology. Of note, recent multiregional sequencing-based studies focused not only on IPMN multi-step tumourigenesis, but also on the divergent intratumoural heterogeneity of this neoplasm. Globally considered, there are three different situations in which co-occurring IPMNs and invasive carcinomas can be found in the same pancreata, indicated with different terminologies: (1) IPMN-associated carcinoma: this definition indicates a carcinoma arising from an IPMN and can be also defined as IPMN-derived carcinoma, sequential or likely related; (2) independent IPMN and invasive carcinoma: the two lesions are not related, and this situation is defined as concomitant, de novo or likely independent; (3) branch-off pathway, where an invasive carcinoma and an adjacent IPMN develop divergently in a forked fashion from a common ancestral clone. In this review, we aim at clarifying the most important nomenclature/definitions of these different situations, also providing an overview of the molecular state-of-the-art and of the clinical implications of this complex landscape.

Clinical trajectory of intraductal papillary mucinous neoplasms progressing to pancreatic carcinomas during long-term surveillance: a prospective series of 100 carcinoma cases

BACKGROUND

Trajectories of serological and morphological signatures have not been documented in pancreatic carcinogenesis related to intraductal papillary mucinous neoplasms (IPMNs).

METHODS

Using a prospective cohort of 3437 IPMN patients, we identified 100 IPMN patients who developed pancreatic carcinomas during long-term surveillance. We examined serial changes of blood markers (carbohydrate antigen 19-9 [CA19-9], hemoglobin A1c [HbA1c], and pancreatic enzymes) and morphological features (worrisome features and high-risk stigmata) during the prediagnostic period of pancreatic carcinomas, overall and by carcinoma types (IPMN-derived vs. concomitant pancreatic carcinomas).

RESULTS

CA19-9 elevation was observed in 39 patients and was associated with a metastatic stage. Compared to IPMN-derived carcinomas, concomitant carcinomas were more likely to represent CA19-9 elevation (60% vs. 30%, respectively; P = 0.005). HbA1c levels elevated only in 3 patients. Pancreatic enzyme elevation was observed in 18 patients with no differences in frequencies between the carcinoma types. All patients with elevated levels of blood markers had positive findings on cross-sectional imaging. High-risk stigmata or worrisome features were observed in all patients but one with concomitant carcinoma. The most common types of worrisome features were the main pancreatic duct dilatation and CA19-9 elevation in IPMN-derived and concomitant carcinomas, respectively. Compared to IPMN-derived carcinomas, concomitant carcinomas were less likely to harbor high-risk stigmata (16% vs. 86%, respectively; P < 0.001).

CONCLUSIONS

The usefulness of currently available blood biomarkers was limited in early detection of pancreatic carcinomas related to IPMNs. Morphological alterations were well correlated with long-term risk of IPMN-derived carcinomas, but not with that of concomitant carcinomas.

Current status of molecular diagnostic approaches using liquid biopsy

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive and lethal cancers, and developing an efficient and reliable approach for its early-stage diagnosis is urgently needed. Precancerous lesions of PDAC, such as pancreatic intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasms (IPMN), arise through multiple steps of driver gene alterations in KRAS, TP53, CDKN2A, SMAD4, or GNAS. Hallmark mutations play a role in tumor initiation and progression, and their detection in bodily fluids is crucial for diagnosis. Recently, liquid biopsy has gained attention as an approach to complement pathological diagnosis, and in addition to mutation signatures in cell-free DNA, cell-free RNA, and extracellular vesicles have been investigated as potential diagnostic and prognostic markers. Integrating such molecular information to revise the diagnostic criteria for pancreatic cancer can enable a better understanding of the pathogenesis underlying inter-patient heterogeneity, such as sensitivity to chemotherapy and disease outcomes. This review discusses the current diagnostic approaches and clinical applications of genetic analysis in pancreatic cancer and diagnostic attempts by liquid biopsy and molecular analyses using pancreatic juice, duodenal fluid, and blood samples. Emerging knowledge in the rapidly advancing liquid biopsy field is promising for molecular profiling and diagnosing pancreatic diseases with significant diversity.

Prediction of malignant intraductal papillary mucinous neoplasm: A nomogram based on clinical information and radiological outcomes

OBJECTIVE

Clinical practitioners face a significant challenge in maintaining a healthy balance between overtreatment and missed diagnosis in the management of intraductal papillary mucinous neoplasm (IPMN). The current study aimed to identify significant risk factors of malignant IPMN from a series of clinical and radiological parameters that are widely available and noninvasive and develop a method to individually predict the risk of malignant IPMN to improve its management.

METHODS

We retrospectively investigated 168 patients who were pathologically diagnosed with IPMN after individualized pancreatic resection between June, 2012 and December, 2020. Independent predictors determined using both univariate and multivariate analyses to construct a predictive model. The discriminatory power of the nomogram was assessed using the area under the receiver operating characteristic curve (AUC). Decision curve analysis was performed to demonstrate the clinical usefulness of the nomogram. Internal cross validation was performed to assess the validity of the predictive model.

RESULTS

In the multivariate analysis, five significant independent risk factors were identified: increased serum CA19-9 level, low prognostic nutritional index (PNI), cyst size, enhancing mural nodule, and main pancreatic duct diameter. The nomogram based on the parameters mentioned above had outstanding performance in distinguishing malignancy, with an AUC of 0.907 (95% confidence interval: 0.859-0.956, p < 0.05), which remained 0.875 after internal cross-validation, and showed good clinical usefulness.

CONCLUSION

A novel nomogram for predicting malignant IPMN first introducing PNI was developed, which may aid in improving IPMN management. Nevertheless, external validation is required to confirm its efficacy.

Clinical Outcomes of Intraductal Papillary Mucinous Neoplasms With Dilatation of the Main Pancreatic Duct

BACKGROUND & AIMS

Dilatation of the main pancreatic duct (MPD) has been a surgical indication for intraductal papillary mucinous neoplasms (IPMNs). Few studies have investigated long-term outcomes of IPMNs with MPD dilatation.

METHODS

Among 3610 patients diagnosed with pancreatic cysts between 1994 and 2021, we identified 2829 IPMN patients, including 282 patients with MPD ≥5 mm, and examined short-term (≤6 months) and long-term risks of pancreatic carcinoma. Utilizing competing risks proportional hazards models, we estimated subdistribution hazard ratios for incidence of pancreatic carcinoma with adjustment for potential confounders.

RESULTS

In analyses of short-term outcomes of the 282 patients with MPD dilatation, 72 (26%) patients were diagnosed with pancreatic carcinoma based on surgical or nonsurgical exploration. During long-term follow-up of 168 patients, we documented 24 (14%) patients diagnosed with pancreatic carcinoma (18 with IPMN-derived carcinoma and 6 with concomitant ductal adenocarcinoma). The patients with the MPD = 5-9.9 mm had cumulative incidence rates of pancreatic carcinoma diagnosis of 8.1% (95% confidence interval [CI], 4.3%-13.5%) and 10.0% (95% CI, 5.5%-15.9%) at 2 and 5 years, respectively; and the patients with the MPD ≥10 mm had the corresponding rates of 16.0% (95% CI, 3.6-36.5%) and 33.3% (95% CI, 10.3%-58.8%). The multivariable subdistribution hazard ratios were 2.78 (95% CI, 1.57-4.90) and 7.00 (95% CI, 2.58-19.0) for the MPD = 5-9.9 mm and ≥10 mm (vs <5 mm), respectively.

CONCLUSIONS

IPMNs with MPD dilatation at baseline were associated with higher prevalence and incidence of pancreatic carcinoma compared with IPMNs with no MPD dilatation.

Multiplex Digital PCR Assay to Detect Multiple KRAS and GNAS Mutations Associated with Pancreatic Carcinogenesis from Minimal Specimen Amounts

Digital PCR (dPCR) allows for highly sensitive quantification of low-frequency mutations and facilitates early detection of cancer. However, low-throughput targeting of single hotspots in dPCR hinders variant specification when multiple probes are used. We developed a dPCR method to simultaneously identify major variants related to pancreatic carcinogenesis. Using a two-dimensional plot of droplet fluorescence under the optimized concentration of two fluorescent probe pools, the absolute quantification of different KRAS and GNAS variants was determined. Successful detection of the multiple driver mutations was verified in 24 surgically resected tumor samples from 19 patients and 22 fine-needle aspiration samples from patients with pancreatic ductal adenocarcinoma. Precise quantification of the variant allele frequency was optimized by using template DNA at a concentration as low as 1 to 10 ng. Furthermore, amplicons targeting multiple hotspots were successfully enriched with fewer false-positive findings using high-fidelity polymerase, allowing for the detection of various KRAS and GNAS mutations with high probability in small amount of cell/tissue specimens. Using this target enrichment, mutations at a rate of 90% in small residual tissues, such as the fine-needle aspiration needle flush and microscopic lesions in resected specimens, were successfully identified. The proposed method allows for low-cost, accurate detection of driver mutations to diagnose cancers, even with minimal tissue collection.

Current Status of the Diagnosis of Early-Stage Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) can be treated with surgery, chemotherapy, and radiotherapy. Despite medical progress in each field in recent years, it is still insufficient for managing PDAC, and at present, the only curative treatment is surgery. A typical pancreatic cancer is relatively easy to diagnose with imaging. However, it is often not recommended for surgical treatment at the time of diagnosis due to metastatic spread beyond the pancreas. Even if it is operable, it often recurs during postoperative follow-up. In the case of PDAC with a diameter of 10 mm or less, the 5-year survival rate is as good as 80% or more, and the best index for curative treatment is tumor size. The early detection of pancreatic cancer with a diameter of less than 10 mm or carcinoma in situ is critical. Here, we provide an overview of the current status of diagnostic imaging features and genetic tests for the accurate diagnosis of early-stage PDAC.

Comprehensive Analysis of Molecular Biologic Characteristics of Pancreatic Ductal Adenocarcinoma Concomitant with Intraductal Papillary Mucinous Neoplasm

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) concomitant with intraductal papillary mucinous neoplasm (IPMN) is defined as PDAC occurring apart from IPMN. This study comprehensively investigated the molecular biologic characteristics of PDAC concomitant with IPMN in major genetic alterations, tumor microenvironment, and prognosis by contrast with those of conventional PDAC.

METHODS

The study retrospectively reviewed the data of 158 surgically resected PDAC patients. The driver gene alteration status (KRAS, TP53, CDKN2A, SMAD4, and GNAS) together with the immune and fibrotic status in tumor was evaluated. The prognosis of PDAC concomitant with IPMN and that of conventional PDAC also were compared.

RESULTS

No statistically significant difference was found between PDAC concomitant with IPMN and conventional PDAC in the alteration frequency analysis of the major driver genes and the immune and fibrotic status in the tumor microenvironment. Overall survival and disease-free survival between patients who had PDAC concomitant with IPMN and those who had conventional PDAC did not show statistically significant differences in propensity-matched subjects. Furthermore, the co-existence of IPMN was not a poor prognostic factor in the multivariable-adjusted Cox proportional hazards model (hazard ratio, 0.95; 95 % confidence interval, 0.51-1.78).

CONCLUSIONS

In this study, PDAC concomitant with IPMN had tumor characteristics similar to those of conventional PDAC in terms of the major driver gene alterations, tumor microenvironment, and prognosis.

Deep learning on time series laboratory test results from electronic health records for early detection of pancreatic cancer

The multi-modal and unstructured nature of observational data in Electronic Health Records (EHR) is currently a significant obstacle for the application of machine learning towards risk stratification. In this study, we develop a deep learning framework for incorporating longitudinal clinical data from EHR to infer risk for pancreatic cancer (PC). This framework includes a novel training protocol, which enforces an emphasis on early detection by applying an independent Poisson-random mask on proximal-time measurements for each variable. Data fusion for irregular multivariate time-series features is enabled by a "grouped" neural network (GrpNN) architecture, which uses representation learning to generate a dimensionally reduced vector for each measurement set before making a final prediction. These models were evaluated using EHR data from Columbia University Irving Medical Center-New York Presbyterian Hospital. Our framework demonstrated better performance on early detection (AUROC 0.671, CI 95% 0.667 - 0.675, p < 0.001) at 12 months prior to diagnosis compared to a logistic regression, xgboost, and a feedforward neural network baseline. We demonstrate that our masking strategy results greater improvements at distal times prior to diagnosis, and that our GrpNN model improves generalizability by reducing overfitting relative to the feedforward baseline. The results were consistent across reported race. Our proposed algorithm is potentially generalizable to other diseases including but not limited to cancer where early detection can improve survival.

Mucin 5AC-Mediated CD44/ITGB1 Clustering Mobilizes Adipose-Derived Mesenchymal Stem Cells to Modulate Pancreatic Cancer Stromal Heterogeneity

BACKGROUND & AIMS

Secreted mucin 5AC (MUC5AC) promotes pancreatic cancer (PC) progression and chemoresistance, suggesting its clinical association with poor prognosis. RNA sequencing analysis from the autochthonous pancreatic tumors showed a significant stromal alteration on genetic ablation of Muc5ac. Previously, depletion or targeting the stromal fibroblasts showed an ambiguous effect on PC pathogenesis. Hence, identifying the molecular players and mechanisms driving fibroblast heterogeneity is critical for improved clinical outcomes.

METHODS

Autochthonous murine models of PC (Kras^G12D, Pdx1-Cre [KC] and Kras^G12D, Pdx1-Cre, Muc5ac^-/- [KCM]) and co-implanted allografts of murine PC cell lines (Muc5ac wild-type and CRISPR/Cas knockout) with adipose-derived mesenchymal stem cells (AD-MSCs) were used to assess the role of Muc5ac in stromal heterogeneity. Proliferation, migration, and surface expression of cell-adhesion markers on AD-MSCs were measured using live-cell imaging and flow cytometry. MUC5AC-interactome was investigated using mass-spectrometry and enzyme-linked immunosorbent assay.

RESULTS

The KCM tumors showed a significant decrease in the expression of α-smooth muscle actin and fibronectin compared with histology-matched KC tumors. Our study showed that MUC5AC, carrying tumor secretome, gets enriched in the adipose tissues of tumor-bearing mice and patients with PC, promoting CD44/CD29 (integrin-β1) clustering that leads to Rac1 activation and migration of AD-MSCs. Furthermore, treatment with KC-derived serum enhanced proliferation and migration of AD-MSCs, which was abolished on Muc5ac-depletion or pharmacologic inhibition of CXCR2 and Rac1, respectively. The AD-MSCs significantly contribute toward α-smooth muscle actin-positive cancer-associated fibroblasts population in Muc5ac-dependent manner, as suggested by autochthonous tumors, co-implantation xenografts, and patient tumors.

CONCLUSION

MUC5AC, secreted during PC progression, enriches in adipose and enhances the mobilization of AD-MSCs. On recruitment to pancreatic tumors, AD-MSCs proliferate and contribute towards stromal heterogeneity.

Current Pathology Model of Pancreatic Cancer

Pancreatic cancer (PC) is one of the most aggressive and lethal malignant neoplasms, ranking in seventh place in the world in terms of the incidence of death, with overall 5-year survival rates still below 10%. The knowledge about PC pathomechanisms is rapidly expanding. Daily reports reveal new aspects of tumor biology, including its molecular and morphological heterogeneity, explain complicated "cross-talk" that happens between the cancer cells and tumor stroma, or the nature of the PC-associated neural remodeling (PANR). Staying up-to-date is hard and crucial at the same time. In this review, we are focusing on a comprehensive summary of PC aspects that are important in pathologic reporting, impact patients' outcomes, and bring meaningful information for clinicians. Finally, we show promising new trends in diagnostic technologies that might bring a difference in PC early diagnosis.

MNX1-HNF1B Axis Is Indispensable for Intraductal Papillary Mucinous Neoplasm Lineages

BACKGROUND & AIMS

Chromatin architecture governs cell lineages by regulating the specific gene expression; however, its role in the diversity of cancer development remains unknown. Among pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMN) with an associated invasive carcinoma (IPMNinv) arise from 2 distinct precursors, and their fundamental differences remain obscure. Here, we aimed to assess the difference of chromatin architecture regulating the transcriptional signatures or biological features in pancreatic cancers.

METHODS

We established 28 human organoids from distinct subtypes of pancreatic tumors, including IPMN, IPMNinv, and PDAC. We performed exome sequencing (seq), RNA-seq, assay for transposase-accessible chromatin-seq, chromatin immunoprecipitation-seq, high-throughput chromosome conformation capture, and phenotypic analyses with short hairpin RNA or clustered regularly interspaced short palindromic repeats interference.

RESULTS

Established organoids successfully reproduced the histology of primary tumors. IPMN and IPMNinv organoids harbored GNAS, RNF43, or KLF4 mutations and showed the distinct expression profiles compared with PDAC. Chromatin accessibility profiles revealed the gain of stomach-specific open regions in IPMN and the pattern of diverse gastrointestinal tissues in IPMNinv. In contrast, PDAC presented an impressive loss of accessible regions compared with normal pancreatic ducts. Transcription factor footprint analysis and functional assays identified that MNX1 and HNF1B were biologically indispensable for IPMN lineages. The upregulation of MNX1 was specifically marked in the human IPMN lineage tissues. The MNX1-HNF1B axis governed a set of genes, including MYC, SOX9, and OLFM4, which are known to be essential for gastrointestinal stem cells. High-throughput chromosome conformation capture analysis suggested the HNF1B target genes to be 3-dimensionally connected in the genome of IPMNinv.

CONCLUSIONS

Our organoid analyses identified the MNX1-HNF1B axis to be biologically significant in IPMN lineages.

Mutant GNAS limits tumor aggressiveness in established pancreatic cancer via antagonizing the KRAS-pathway

BACKGROUND

Mutations in GNAS drive pancreatic tumorigenesis and frequently occur in intraductal papillary mucinous neoplasm (IPMN); however, their value as a therapeutic target is yet to be determined. This study aimed at evaluating the involvement of mutant GNAS in tumor aggressiveness in established pancreatic cancer.

METHODS

CRISPR/Cas9-mediated GNAS R201H silencing was performed using human primary IPMN-associated pancreatic cancer cells. The role of oncogenic GNAS in tumor maintenance was evaluated by conducting cell culture and xenograft experiments, and western blotting and transcriptome analyses were performed to uncover GNAS-driven signatures.

RESULTS

Xenografts of GNAS wild-type cells were characterized by a higher Ki-67 labeling index relative to GNAS-mutant cells. Phenotypic alterations in the GNAS wild-type tumors resulted in a significant reduction in mucin production accompanied by solid with massive stromal components. Transcriptional profiling suggested an apparent conflict of mutant GNAS with KRAS signaling. A significantly higher Notch intercellular domain (NICD) was observed in the nuclear fraction of GNAS wild-type cells. Meanwhile, inhibition of protein kinase A (PKA) induced NICD in GNAS-mutant IPMN cells, suggesting that NOTCH signaling is negatively regulated by the GNAS-PKA pathway. GNAS wild-type cells were characterized by a significant invasive property relative to GNAS-mutant cells, which was mediated through the NOTCH regulatory pathway.

CONCLUSIONS

Oncogenic GNAS induces mucin production, not only via MUC2 but also via MUC5AC/B, which may enlarge cystic lesions in the pancreas. The mutation may also limit tumor aggressiveness by attenuating NOTCH signaling; therefore, such tumor-suppressing effects must be considered when therapeutically inhibiting the GNAS pathway.

Pancreatic medullary carcinoma developed on a pancreatic intraductal papillary mucinous neoplasm with loss of MSH2 and MSH6 expression: a case report

BACKGROUND

Pancreatic medullary carcinoma (PMC) is a rare pancreatic tumor, usually showing the presence of microsatellite instability, mostly MLH1 silencing, and a wild-type KRAS mutation status. We report here a PMC arising from a Pancreatic Intraductal Papillary Mucinous Neoplasm (IPMN), both having KRAS and TP53 mutations.

CASE PRESENTATION

We report the case of a 73-year-old woman presenting with right iliac fossa pain. MRI revealed a 16 mm diameter mass in the pancreas, leading to a pancreatic duct stricture and upstream a dilatation of the distal pancreatic duct of Wirsung. A fine needle aspiration was performed, and pathology analysis revealed malignant glandular cells. The patient underwent distal pancreatectomy. Gross examination revealed an12 mm indurated white lesion, adjacent to a cystic lesion extending into the rest of the pancreatic body. Microscopically, the cystic area represented a mixed (gastric-type and pancreatobiliary-type) IPMN, involving the main and secondary pancreatic ducts with low-grade and high-grade dysplasia. In the periphery of this IPMN, a 14mm associated invasive carcinoma was observed, characterized by focal gland formation and by poorly differentiated cells with a syncytial appearance, associated with a dense lymphoplasmocytic and neutrophilic infiltrate. Immunohistochemical analyses showed loss of MSH2 and MSH6 expression. Microsatellite instability was confirmed by molecular test. Molecular analysis was performed both on the invasive carcinoma and on the high-grade dysplasia IPMN, revealing the same mutation profile with KRAS and TP53 mutations. The proposed diagnosis was mixed IPMN with associated invasive medullary carcinoma that presented loss of MSH2 and MSH6 expression.

CONCLUSIONS

The present case reports for the first time, at the best of our knowledge, the coexistence of IPMN lesions and PMC, both having the same molecular alterations. It also describes the second case of PMC with microsatellite instability, MSH2 and MSH6 silenced.

Humoral Predictors of Malignancy in IPMN: A Review of the Literature

Pancreatic cystic lesions are increasingly detected in cross-sectional imaging. Intraductal papillary mucinous neoplasm (IPMN) is a mucin-producing subtype of the pancreatic cyst lesions arising from the pancreatic duct system. IPMN is a potential precursor of pancreatic cancer. The transformation of IPMN in pancreatic cancer is progressive and requires the occurrence of low-grade dysplasia, high-grade dysplasia, and ultimately invasive cancer. Jaundice, enhancing mural nodule >5 mm, main pancreatic duct diameter >10 mm, and positive cytology for high-grade dysplasia are considered high-risk stigmata of malignancy. While increased levels of carbohydrate antigen 19-9 (CA 19-9) (>37 U/mL), main pancreatic duct diameter 5-9.9 mm, cyst diameter >40 mm, enhancing mural nodules <5 mm, IPMN-induced acute pancreatitis, new onset of diabetes, cyst grow-rate >5 mm/year are considered worrisome features of malignancy. However, cross-sectional imaging is often inadequate in the prediction of high-grade dysplasia and invasive cancer. Several studies evaluated the role of humoral and intra-cystic biomarkers in the prediction of malignancy in IPMN. Carcinoembryonic antigen (CEA), CA 19-9, intra-cystic CEA, intra-cystic glucose, and cystic fluid cytology are widely used in clinical practice to distinguish between mucinous and non-mucinous cysts and to predict the presence of invasive cancer. Other biomarkers such as cystic fluid DNA sequencing, microRNA (mi-RNA), circulating microvesicles, and liquid biopsy are the new options for the mini-invasive diagnosis of degenerated IPMN. The aim of this study is to review the literature to assess the role of humoral and intracystic biomarkers in the prediction of advanced IPMN with high-grade dysplasia or invasive carcinoma.

The Potential of Induced Pluripotent Stem Cells to Advance the Treatment of Pancreatic Ductal Adenocarcinoma

Simple Summary

Despite improvements in the treatment of several cancer types, the extremely poor prognosis of pancreatic cancer patients has remained unchanged over the last decades. Therefore, new therapeutic regimens for pancreatic cancer are highly needed. In this review, we will discuss the potential of induced pluripotent stem cells (iPSCs) to generate representative pancreatic cancer models that can aid the development of novel diagnostics and therapeutic strategies. Furthermore, the potential of iPSCs as pancreatic cancer vaccines or as a basis for cellular therapies will be discussed. With promising preclinical results and ongoing clinical trials, the potential of iPSCs to further the treatment of pancreatic cancer is being explored and, in turn, will hopefully provide additional therapies to increase the poor survival rates of this patient population.

Abstract

Advances in the treatment of pancreatic ductal adenocarcinoma (PDAC) using neoadjuvant chemoradiotherapy, chemotherapy, and immunotherapy have had minimal impact on the overall survival of patients. A general lack of immunogenic features and a complex tumor microenvironment (TME) are likely culprits for therapy refractoriness in PDAC. Induced pluripotent stem cells (iPSCs) should be explored as a means to advance the treatment options for PDAC, by providing representative in vitro models of pancreatic cancer development. In addition, iPSCs could be used for tailor-made cellular immunotherapies or as a source of tumor-associated antigens in the context of vaccination.

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.

Updates in diagnosis and management of pancreatic cysts

Incidental pancreatic cysts are commonly encountered with some cysts having malignant potential. The most common pancreatic cystic neoplasms include serous cystadenoma, mucinous cystic neoplasm and intraductal papillary mucinous neoplasm. Risk stratifying pancreatic cysts is important in deciding whether patients may benefit from endoscopic ultrasound (EUS) or surgical resection. Surgery should be reserved for patients with malignant cysts or cysts at high risk for developing malignancy as suggested by various risk features including solid mass, nodule and dilated main pancreatic duct. EUS may supplement magnetic resonance imaging findings for cysts that remain indeterminate or have concerning features on imaging. Various cyst fluid markers including carcinoembryonic antigen, glucose, amylase, cytology, and DNA markers help distinguish mucinous from nonmucinous cysts. This review will guide the practicing gastroenterologist in how to evaluate incidental pancreatic cysts and when to consider referral for EUS or surgery. For presumed low risk cysts, surveillance strategies will be discussed. Managing pancreatic cysts requires an individualized approach that is directed by the various guidelines.

Prognostic significance of skeletal muscle decrease in unresectable pancreatic cancer: Survival analysis using the Weibull exponential distribution model

BACKGROUND/OBJECTIVES

Decrease in skeletal muscle mass and function is associated with a poor prognosis following surgical resection of pancreatic ductal adenocarcinomas (PDAs). This study evaluated whether skeletal muscle mass decrease affects PDA outcomes.

METHODS

Data of 112 patients with advanced and unresectable PDA who underwent chemotherapy in a single institution were retrospectively analyzed. Information on age, sex, hematological investigations, including systemic inflammation-based markers and nutritional assessment biomarkers, and imaging parameters of skeletal muscle mass and visceral adipose tissue were retrieved from the patients' medical records. The efficiency of the Cox, Weibull, and standardized exponential models were compared using hazard ratios and the Akaike Information Criterion (AIC).

RESULTS

Results from the Weibull, Cox, and standardized exponential model analyses indicated that low skeletal muscle mass, Eastern Cooperative Oncology Group performance status (PS), and the requirement of biliary drainage were associated with the highest risk of death, followed by carcinoembryonic antigen (CEA) levels and the presence of ascites. The AIC value from the four significant parameters was lowest for the Weibull-exponential distribution (222.3) than that of the Cox (653.7) and standardized exponential models (265.7). We developed a model for estimating the 1-year survival probability using the Weibull-exponential distribution.

CONCLUSIONS

Low-skeletal muscle index, PS, requirement of biliary drainage, CEA levels, and presence of ascites are independent factors for predicting poor patient survival after chemotherapy. Improved survival modeling using a parametric approach may accurately predict the outcome of patients with advanced-stage PDA.

Screening for pancreatic cancer: a review for general clinicians

Pancreatic cancer (PC) is an exceptionally lethal malignancy with increasing incidence and mortality worldwide. One of the principal challenges in the treatment of PC is that the diagnosis is usually made at a late stage when potentially curative surgical resection is no longer an option. General clinicians including internists and family physicians are well positioned to identify high-risk individuals and refer them to centers with expertise in PC screening and treatment where screening modalities can be employed. Here, we provide an up-to-date review of PC precursor lesions, epidemiology, and risk factors to empower the general clinician to recognize high-risk patients and employ risk reduction strategies. We also review current screening guidelines and modalities and preview progress that is being made to improve screening tests and biomarkers. It is our hope that this review article will empower the general clinician to understand which patients need to be screened for PC, strategies that may be used to reduce PC risk, and which screening modalities are available in order to diminish the lethality of PC.

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.

More than acinar identity? A novel cystic phenotype suggests broader roles for NR5A2 in pancreatic cancer†

The prognosis for pancreatic ductal adenocarcinoma (PDAC) remains dismal. Multiple genome-wide association studies (GWAS) have implicated the nuclear receptor NR5A2 in modulating PDAC risk, but mechanisms for this association are not understood. NR5A2 is a transcription factor that maintains acinar cell identity, and heterozygous loss of Nr5a2 in mice accelerates oncogenic Kras-driven formation of pancreatic intraepithelial neoplasia (PanIN), a PDAC precursor derived from acinar cells. In a recent issue of The Journal of Pathology, Cobo et al characterize a novel mouse model that uses Ptf1a:Cre to drive oncogenic Kras as well as heterozygous Nr5a2 inactivation. In addition to the expected PanIN lesions, these mice exhibited a surprising phenotype: large pancreatic cystic lesions which have not been previously reported. Comparing expression of oncogenic Kras and heterozygous Nr5a2 in various mouse models reveals several possible explanations for these cystic lesions. Importantly, these differences across mouse models suggest that NR5A2 may contribute to PDAC precursors in ways beyond its previously characterized acinar cell-autonomous role. These observations highlight that pathways implicated by GWAS may have roles in unexpected cell types, and an understanding of these roles will be critical to guide new preventive and treatment strategies for PDAC. © 2021 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

ABO Blood Group and Risk of Pancreatic Carcinogenesis in Intraductal Papillary Mucinous Neoplasms

BACKGROUND

ABO blood group has been associated with risks of various malignancies, including pancreatic cancer. No study has evaluated the association of ABO blood group with incidence of pancreatic carcinogenesis during follow-up of patients with intraductal papillary mucinous neoplasms (IPMN).

METHODS

Among 3,164 patients diagnosed with pancreatic cysts at the University of Tokyo (Tokyo, Japan) from 1994 through 2019, we identified 1,815 patients with IPMN with available data on ABO blood group. We studied the association of ABO blood group with incidence of pancreatic carcinoma, overall and by carcinoma types [IPMN-derived carcinoma or concomitant pancreatic ductal adenocarcinoma (PDAC)]. Utilizing competing-risks proportional hazards models, we estimated subdistribution hazard ratios (SHR) for incidence of pancreatic carcinoma with adjustment for potential confounders, including cyst characteristics.

RESULTS

During 11,518 person-years of follow-up, we identified 97 patients diagnosed with pancreatic carcinoma (53 with IPMN-derived carcinoma and 44 with concomitant PDAC). Compared with patients with blood group O, patients with blood groups A, B, and AB had multivariable SHRs (95% confidence intervals) for pancreatic carcinoma of 2.25 (1.25-4.07; P = 0.007), 2.09 (1.08-4.05; P = 0.028), and 1.17 (0.43-3.19; P = 0.76), respectively. We observed no differential association of ABO blood group with pancreatic carcinoma incidence by carcinoma types.

CONCLUSIONS

In this large long-term study, patients with IPMN with blood group A or B appeared to be at higher risk of pancreatic carcinoma compared with those with blood group O.

IMPACT

ABO blood group can be a biomarker for pancreatic cancer risk among patients with IPMNs.

Assessment of Malignancy Potential in Intraductal Papillary Mucinous Neoplasms of the Pancreas on MDCT

RATIONALE AND OBJECTIVE

To assess the malignancy potential of intraduct papillary mucinous neoplasms (IPMNs) on multidetector-row computerized tomography according to the 2012 International Consensus Guidelines (ICG).

MATERIALS AND METHODS

This study retrospectively collected IPMNs confirmed by surgery from 2016 to 2019. The imaging findings of IPMNs were analyzed. IPMNs were classified as malignancy in the presence of high-grade dysplasia or invasive carcinoma and began in the presence of low- and intermediate-grade dysplasia.

RESULTS

A total of 207 patients (mean age: 63.7 ± 7.9 years) were included, and the prevalence of malignancy was 28.0% (58 of 207). According to the 2012 ICG, the imaging findings of IPMNs were divided into worrisome features (WFs) and high-risk stigmata (HRS). The malignancy of IPMN with only one WF was relatively low (1.4%, 3 of 207). In multivariate regression analyses, the independent factors of IPMNs were enhanced mural nodule ≥5 mm (odds ratio [OR] = 19.5, 95% confidence interval [CI] 6.8-55.4), abrupt change in the main pancreatic duct caliber with distal pancreatic atrophy (OR = 4.6, 95%CI 1.67-12.71), and thickened enhanced cyst walls (OR = 2.9, 95%CI 1.1-8.2). When the presence of more than two WFs or HRS (score ≥ 3) was regarded as indicating the malignancy potential of IPMNs on multidetector-row computerized tomography, the sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were 89.7%, 75.8%, 79.7%, 59.1%, and 95.0%, respectively.

CONCLUSION

According to the ICG in 2012, patients with IPMNs with only one WF have a low risk for malignancy, and the presence of at least two WFs or any HRS (score ≥3) suggests malignant IPMNs.

Modeling plasticity and dysplasia of pancreatic ductal organoids derived from human pluripotent stem cells

Personalized in vitro models for dysplasia and carcinogenesis in the pancreas have been constrained by insufficient differentiation of human pluripotent stem cells (hPSCs) into the exocrine pancreatic lineage. Here, we differentiate hPSCs into pancreatic duct-like organoids (PDLOs) with morphological, transcriptional, proteomic, and functional characteristics of human pancreatic ducts, further maturing upon transplantation into mice. PDLOs are generated from hPSCs inducibly expressing oncogenic GNAS, KRAS, or KRAS with genetic covariance of lost CDKN2A and from induced hPSCs derived from a McCune-Albright patient. Each oncogene causes a specific growth, structural, and molecular phenotype in vitro. While transplanted PDLOs with oncogenic KRAS alone form heterogenous dysplastic lesions or cancer, KRAS with CDKN2A loss develop dedifferentiated pancreatic ductal adenocarcinomas. In contrast, transplanted PDLOs with mutant GNAS lead to intraductal papillary mucinous neoplasia-like structures. Conclusively, PDLOs enable in vitro and in vivo studies of pancreatic plasticity, dysplasia, and cancer formation from a genetically defined background.

Resection of pancreatic cystic neoplasms in recurrent acute pancreatitis prevents recurrent pancreatitis but does not identify more malignancies

BACKGROUND

Recurrent acute pancreatitis (RAP) may be a presenting feature of and an indication for resection of pancreatic cysts, including intra-ductal papillary mucinous neoplasm (IPMN). Few data are available regarding the prevalence of malignancy and post-operative RAP in this population.

AIM

To study the role of resection to help prevent RAP and analyze if presentation as RAP would be a predictor for malignancy.

METHODS

This retrospective study assessed 172 patients who underwent surgical resection of pancreatic cystic neoplasms at a university hospital between 2002 and 2016. The prevalence of preoperative high-risk cyst features, and of neoplasia was compared between patients with and without RAP. To identify the cause of pancreatitis, all the patients had a detailed history of alcohol, smoking, medications obtained, and had cross-sectional imaging (contrast-enhanced computed tomography/magnetic resonance imaging) and endoscopic ultrasound to look for gallstone etiology and other structural causes for pancreatitis. The incidence of RAP post-resection was the primary outcome.

RESULTS

IPMN accounted for 101 cases (58.7%) {[branch duct (BD) 59 (34.3%), main duct (MD) 42] (24.4%)}. Twenty-nine (16.9%) presented with RAP (mean 2.2 episodes): 15 had BD-IPMN, 8 MD-IPMN, 5 mucinous cystic neoplasm and 1 serous cystic neoplasm. Malignancy was similar among those with vs without RAP for all patients [6/29 (20.7%) vs 24/143 (16.8%)] and IPMN patients [6/23 (26.1%) vs 23/78 (29.5%)], although tended to be higher with RAP in BD-IPMN, [5/15 (33.3%) vs 3/44 (6.8%), P = 0.04]. At mean follow-up of 7.2 years, 1 (3.4%) RAP patient had post-resection RAP. The mean episodes of acute pancreatitis before vs after surgery were 3.4 vs 0.02 (P < 0.0001).

CONCLUSION

Malignancy was not increased in patients with pancreatic cystic neoplasms who have RAP compared to those without RAP. In addition, specific cyst charac-teristics were not clearly associated with RAP. The incidence of RAP was markedly decreased in almost all patients following cyst resection.

Visual Analytics of a Computer-Aided Diagnosis System for Pancreatic Lesions

Machine learning is a powerful and effective tool for medical image analysis to perform computer-aided diagnosis (CAD). Having great potential in improving the accuracy of a diagnosis, CAD systems are often analyzed in terms of the final accuracy, leading to a limited understanding of the internal decision process, impossibility to gain insights, and ultimately to skepticism from clinicians. We present a visual analytics approach to uncover the decision-making process of a CAD system for classifying pancreatic cystic lesions. This CAD algorithm consists of two distinct components: random forest (RF), which classifies a set of predefined features, including demographic features, and a convolutional neural network (CNN), which analyzes radiological (imaging) features of the lesions. We study the class probabilities generated by the RF and the semantical meaning of the features learned by the CNN. We also use an eye tracker to better understand which radiological features are particularly useful for a radiologist to make a diagnosis and to quantitatively compare with the features that lead the CNN to its final classification decision. Additionally, we evaluate the effects and benefits of supplying the CAD system with a case-based visual aid in a second-reader setting.

Pre-Operative Imaging and Pathological Diagnosis of Localized High-Grade Pancreatic Intra-Epithelial Neoplasia without Invasive Carcinoma

Pancreatic ductal adenocarcinoma (PDAC) arises from precursor lesions, such as pancreatic intra-epithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN). The prognosis of high-grade precancerous lesions, including high-grade PanIN and high-grade IPMN, without invasive carcinoma is good, despite the overall poor prognosis of PDAC. High-grade PanIN, as a lesion preceding invasive PDAC, is therefore a primary target for intervention. However, detection of localized high-grade PanIN is difficult when using standard radiological approaches. Therefore, most studies of high-grade PanIN have been conducted using specimens that harbor invasive PDAC. Recently, imaging characteristics of high-grade PanIN have been revealed. Obstruction of the pancreatic duct due to high-grade PanIN may induce a loss of acinar cells replaced by fibrosis and lobular parenchymal atrophy. These changes and additional inflammation around the branch pancreatic ducts (BPDs) result in main pancreatic duct (MPD) stenosis, dilation, retention cysts (BPD dilation), focal pancreatic parenchymal atrophy, and/or hypoechoic changes around the MPD. These indirect imaging findings have become important clues for localized, high-grade PanIN detection. To obtain pre-operative histopathological confirmation of suspected cases, serial pancreatic-juice aspiration cytologic examination is effective. In this review, we outline current knowledge on imaging characteristics of high-grade PanIN.

Epithelial Nr5a2 heterozygosity cooperates with mutant Kras in the development of pancreatic cystic lesions

Cystic neoplasms of the pancreas are an increasingly important public health problem. The majority of these lesions are benign but some progress to invasive pancreatic ductal adenocarcinoma (PDAC). There is a dearth of mouse models of these conditions. The orphan nuclear receptor NR5A2 regulates development, differentiation, and inflammation. Germline Nr5a2 heterozygosity sensitizes mice to the oncogenic effects of mutant Kras in the pancreas. Here, we show that - unlike constitutive Nr5a2+/- mice - conditional Nr5a2 heterozygosity in pancreatic epithelial cells, combined with mutant Kras (KPN+/- ), leads to a dramatic replacement of the pancreatic parenchyma with cystic structures and an accelerated development of high-grade PanINs and PDAC. Timed histopathological analyses indicated that in KPN+/- mice PanINs precede the formation of cystic lesions and the latter precede PDAC. A single episode of acute caerulein pancreatitis is sufficient to accelerate the development of cystic lesions in KPN+/- mice. Epithelial cells of cystic lesions of KPN+/- mice express MUC1, MUC5AC, and MUC6, but lack expression of MUC2, CDX2, and acinar markers, indicative of a pancreato-biliary/gastric phenotype. In accordance with this, in human samples we found a non-significantly decreased expression of NR5A2 in mucinous tumours, compared with conventional PDAC. These results highlight that the effects of loss of one Nr5a2 allele are time- and cell context-dependent. KPN+/- mice represent a new model to study the formation of cystic pancreatic lesions and their relationship with PanINs and classical PDAC. Our findings suggest that pancreatitis could also contribute to acceleration of cystic tumour progression in patients. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Inherited predisposition to pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer death in the US by 2030. There are multiple germline pathogenic variants and cancer syndromes associated with an increased risk of PDAC. Precision treatment, informed by germline genetic testing and molecular tumor analysis, can optimize therapeutic regimens and outcomes for those diagnosed with PDAC. As a result, the National Comprehensive Cancer Network currently recommends genetic testing for all newly diagnosed PDAC patients given the clinical implications for treatment but also for the identification of at-risk family members who can benefit from pancreatic cancer screening and other cancer prevention strategies. This article reviews inherited risk factors for the development of PDAC and current screening strategies for the early detection of PDAC in high-risk populations.