An illustrated consensus on the classification of pancreatic intraepithelial neoplasia and intraductal papillary mucinous neoplasms

Emerging roles for the IL-6 family of cytokines in pancreatic cancer

Pancreatic cancer has one of the poorest prognoses of all malignancies, with little improvement in clinical outcome over the past 40 years. Pancreatic ductal adenocarcinoma is responsible for the vast majority of pancreatic cancer cases, and is characterised by the presence of a dense stroma that impacts therapeutic efficacy and drives pro-tumorigenic programs. More specifically, the inflammatory nature of the tumour microenvironment is thought to underlie the loss of anti-tumour immunity and development of resistance to current treatments. Inflammatory pathways are largely mediated by the expression of, and signalling through, cytokines, chemokines, and other cellular messengers. In recent years, there has been much attention focused on dual targeting of cancer cells and the tumour microenvironment. Here we review our current understanding of the role of IL-6, and the broader IL-6 cytokine family, in pancreatic cancer, including their contribution to pancreatic inflammation and various roles in pancreatic cancer pathogenesis. We also summarise potential opportunities for therapeutic targeting of these pathways as an avenue towards combating poor patient outcomes.

Expression of CD117, CK17, CK20, MUC4, villin and mismatch repair deficiency in pancreatic intraductal papillary mucinous neoplasm

Among pancreatic intraductal papillary neoplasms, gastric, intestinal, and pancreatobiliary intraductal papillary mucinous neoplasm (IPMN), intraductal oncocytic papillary neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN) have been defined, differing regarding association with invasive carcinoma and prognosis. Immunohistochemistry (IHC) can help in the distinction of these neoplasms, but a proportion is unclassifiable using recommended markers. Hence, additional markers useful for the typing of pancreatic intraductal papillary neoplasms are needed. The reported frequencies of the different types of IPMNs in surgical series vary to some extent, and such data based on Danish patients are currently lacking. Besides, the role of mismatch repair (MMR) deficiency in these neoplasms has not been fully elucidated. We aimed to evaluate the frequency of different types of pancreatic intraductal papillary neoplasms in a Danish cohort. Furthermore, we aimed to examine the utility of CD117, CK17, CK20, MUC4, and villin as markers for their distinction, in addition to the recommended markers MUC1, MUC2, MUC5AC, MUC6 and CDX2, and to evaluate the frequency of MMR deficiency. We typed 40 consecutively resected pancreatic intraductal papillary neoplasms according to the WHO criteria from 2019. IHC for CD117, CDX2, CK17, CK20, MLH1, MSH2, MSH6, MUC1 (H23), MUC1 (Ma695), MUC2, MUC4, MUC5AC, MUC6, PMS2, and villin was performed and evaluated using a five-tiered semiquantitative scale. A subset of the tumours was examined with PCR for microsatellite instability (MSI). Most tumours were intestinal (40 %) and gastric (40 %) IPMNs, followed by pancreatobiliary (17 %) IPMNs and IOPN (3 %). All cases were MMR proficient. We found a higher expression of MUC4, CK20 and villin in intestinal compared to gastric IPMNs (p < 0.01, p < 0.001 and p < 0.001). MUC4 was more strongly expressed in intestinal compared to pancreatobiliary IPMNs, while the opposite was found for CK17 (p < 0.05 and p < 0.05). IOPN showed strong CD117 expression (score 4), while all gastric IPMNs were negative and 50 % and 29 % of intestinal and pancreatobiliary IPMNs only showed weak expression (score 1). Our data suggest that CK20, MUC4 and villin may aid in the identification of intestinal IPMNs, while CK17 and CD117 may aid in the identification of pancreatobiliary IPMNs and IOPN, in some cases. However, additional studies evaluating these markers in pancreatic intraductal papillary neoplasms are needed.

Pancreas image mining: a systematic review of radiomics

OBJECTIVES

To systematically review published studies on the use of radiomics of the pancreas.

METHODS

The search was conducted in the MEDLINE database. Human studies that investigated the applications of radiomics in diseases of the pancreas were included. The radiomics quality score was calculated for each included study.

RESULTS

A total of 72 studies encompassing 8863 participants were included. Of them, 66 investigated focal pancreatic lesions (pancreatic cancer, precancerous lesions, or benign lesions); 4, pancreatitis; and 2, diabetes mellitus. The principal applications of radiomics were differential diagnosis between various types of focal pancreatic lesions (n = 19), classification of pancreatic diseases (n = 23), and prediction of prognosis or treatment response (n = 30). Second-order texture features were most useful for the purpose of differential diagnosis of diseases of the pancreas (with 100% of studies investigating them found a statistically significant feature), whereas filtered image features were most useful for the purpose of classification of diseases of the pancreas and prediction of diseases of the pancreas (with 100% of studies investigating them found a statistically significant feature). The median radiomics quality score of the included studies was 28%, with the interquartile range of 22% to 36%. The radiomics quality score was significantly correlated with the number of extracted radiomics features (r = 0.52, p < 0.001) and the study sample size (r = 0.34, p = 0.003).

CONCLUSIONS

Radiomics of the pancreas holds promise as a quantitative imaging biomarker of both focal pancreatic lesions and diffuse changes of the pancreas. The usefulness of radiomics features may vary depending on the purpose of their application. Standardisation of image acquisition protocols and image pre-processing is warranted prior to considering the use of radiomics of the pancreas in routine clinical practice.

KEY POINTS

• Methodologically sound studies on radiomics of the pancreas are characterised by a large sample size and a large number of extracted features. • Optimisation of the radiomics pipeline will increase the clinical utility of mineable pancreas imaging data. • Radiomics of the pancreas is a promising personalised medicine tool in diseases of the pancreas.

Hyalinized stroma is a characteristic feature of pancreatic intraductal oncocytic papillary neoplasm: An immunohistochemical study

Hyalinized stroma (HS) is a dense, eosinophilic, and amorphous extracellular material in the stroma. HS is observed in several tumors; however, it has not been comprehensively studied in pancreatic intraductal papillary mucinous neoplasm (IPMN) or intraductal oncocytic papillary neoplasm (IOPN). Here, we aimed to evaluate the immunohistochemical and microscopic characteristics of HS in IPMN and IOPN. The prevalence of HS was determined in 168 cases of IPMN, including intestinal type (IPMN-I), gastric type (IPMN-G), and pancreatobiliary type (IPMN-PB), as well as in 11 cases of IOPN. Immunohistochemical staining for laminin and collagen (types I, II, III, IV, and V), as well as Congo red staining were performed in IPMN and IOPN cases containing HS. The prevalence of HS among the IPMN and IOPN specimens was 1.2% (2/168 cases) and 45.5% (5/11 cases), respectively. The prevalence rates of HS in each IPMN subtype were as follows: 2.2% (2/91 cases) in IPMN-G, and 0% in IPMN-PB and IPMN-I. All seven HS cases were positive for collagen I, III, IV, and V but were negative for Congo red staining. Most cases showed negative, focal, or weak expression of laminin and type II collagen. These findings indicate that HS is associated with IOPN and is primarily composed of collagen fibers.

A Morphological and Immunohistochemical Study of the Tumoral and Inflammatory Cells in Pancreatic Ductal Adenocarcinoma

This study is aimed at investigating tumoral and inflammatory cells and the significance of the prognostic factors of pancreatic ductal adenocarcinoma (PDAC); it is also aimed at determining the role of immunohistochemistry in the diagnosis and prognosis of this neoplasm. Materials and Methods. 230 cases of pancreatic ductal adenocarcinoma were included in the study group; these cases were selected from the archives of the Department of Pathology of the Fundeni Clinical Institute over a ten-year period. Immunohistochemistry was performed using the following antibodies: MUC 1, CD 34, Factor VIII, CD 68, MMP-7, CEA, p21, p53, and Ki 67. Results. There were 133 male (57.8%) and 97 female (42.2%) patients included in this study, with ages between 20 and 81 years old (mean age: 58.2 years) and with tumors located in the pancreatic head (n = 196; 85.2%), pancreatic body (n = 12; 5.2%), and pancreatic tail (n = 20, 8.7%), as well as panpancreatic tumors (n = 2; 0.9%). Patients presented with early stages (IA and IB), with low pathologic grade (G1), with small size tumors (less than 1-1.5 cm), with tumors located in the head of the pancreas, (p53: negative; p21: positive; and CD 68: positive in peritumoral tissue), with low nuclear index (Ki 67 < 10%), without metastases at the time of surgery (had a better prognosis), and with a survival rate of about 7 months. Conclusions. Immunohistochemistry is useful for an accurate diagnosis, differential diagnosis, and establishment of additional factors that might have a prognostic importance. It is recommended to study peritumoral tissue from the quantitative and qualitative points of view to increase the number of prognostic factors. This study represents a multidisciplinary approach, and it is a result of teamwork; it presents histopathological methods of examination of this severe illness and describes only a part of the scientific effort to determine the main pathological mechanisms of this neoplasm.

Synchronous Double Bile Duct Cancers with Distinct Genetic Features

A 69-year-old man was referred to our hospital because of appetite loss. Imaging showed a nodular tumor in the perihilar bile duct and a second flat lesion in the distal bile duct. Right hepatopancreaticoduodenectomy was performed, and the histopathological findings demonstrated that the perihilar and distal lesions were moderately and poorly differentiated adenocarcinoma, respectively, and anatomically separated. Furthermore, the resected specimens showed no pancreaticobiliary maljunction. Histological and TP53 gene analyses in a rare case of synchronous double bile duct cancers suggest that there are various genetic pathways through which bile duct cancer develops, highlighting the complexity of its pathogenesis.

The Diagnostic Accuracy of Mutant KRAS Detection from Pancreatic Secretions for the Diagnosis of Pancreatic Cancer: A Meta-Analysis

This meta-analysis aims to identify the diagnostic accuracy of mutations in the Kirsten Rat Sarcoma (KRAS) oncogene in the diagnosis of pancreatic ductal adenocarcinoma (PDAC). The survival of PDAC remains poor often due to the fact that disease is advanced at diagnosis. We analysed 22 studies, with a total of 2156 patients, to identify if the detection of KRAS mutations from pancreatic exocrine secretions yields sufficient specificity and sensitivity to detect patients with PDAC amongst healthy individuals. The majority of the studies were retrospective, samples were obtained endoscopically or surgically, and included comparator populations of patients with chronic pancreatitis and pre-malignant pancreatic lesions (PanIN) as well as healthy controls. We performed several analyses to identify the diagnostic accuracy for PDAC among these patient populations. Our results highlighted that the diagnostic accuracy of KRAS mutation for PDAC was of variable sensitivity and specificity when compared with PanINs and chronic pancreatitis, but had a higher specificity among healthy individuals. The sensitivity of this test must be improved to prevent missing early PDAC or PanINs. This could be achieved with rigorous prospective cohort studies, in which high-risk patients with normal cross-sectional imaging undergo surveillance following KRAS mutation testing.

The importance of circulating and disseminated tumor cells in pancreatic cancer

Pancreatic cancer is a lethal disease in a large part due to the systemic nature at the time of diagnosis. In those patients who undergo a potentially curative resection of pancreatic cancer, the overwhelming majority will have systemic relapse. Circulating tumor cells are an important mediator of the development of metastases. Circulating tumor cells have been identified in patients with clinically localized resectable pancreatic cancer and exist as several phenotypes. Mesenchymal and stem cell-like phenotypes of circulating tumor cells predict early recurrence and worse survival. This review focuses on the current understanding of circulating tumor cells in pancreatic cancer and how this information can be used in developing more effective therapy in the future.

Unraveling ERBB network dynamics upon betacellulin signaling in pancreatic ductal adenocarcinoma in mice

Pancreatic ductal adenocarcinoma (PDAC) will soon belong to the top three cancer killers. The only approved specific PDAC therapy targets the epidermal growth factor receptor (EGFR). Although EGFR is a crucial player in PDAC development, EGFR-based therapy is disappointing. In this study, we evaluated the role of the EGFR ligand betacellulin (BTC) in PDAC. The expression of BTC was investigated in human pancreatic cancer specimen. Then, we generated a BTC knockout mouse model by CRISPR/Cas9 technology and a BTC overexpression model. Both models were crossed with the Ptf1aCre/+ ;KRASG12D/+ (KC) mouse model (B-/- KC or BKC, respectively). In addition, EGFR, ERBB2, and ERBB4 were investigated by the pancreas-specific deletion of each receptor using the Cre-loxP system. Tumor initiation and progression were analyzed in all mouse lines, and the underlying molecular biology of PDAC was investigated at different time points. BTC is expressed in human and murine PDAC. B-/- KC mice showed a decelerated PDAC progression, associated with decreased EGFR activation. BKC mice developed severe PDAC with a poor survival rate. The dramatically increased BTC-mediated tumor burden was EGFR-dependent, but also ERBB4 and ERBB2 were involved in PDAC development or progression, as depletion of EGFR, ERBB2, or ERBB4 significantly improved the survival rate of BTC-mediated PDAC. BTC increases PDAC tumor burden dramatically by enhanced RAS activation. EGFR signaling, ERBB2 signaling, and ERBB4 signaling are involved in accelerated PDAC development mediated by BTC indicating that targeting the whole ERBB family, instead of a single receptor, is a promising strategy for the development of future PDAC therapies.

Validation of the clinical utility of 4 guidelines in the initial triage of mucinous cystic lesions of the pancreas based on cross-sectional imaging: Experience with 188 surgically-treated patients

INTRODUCTION

Over the years, several guidelines have been introduced to guide management of mucinous pancreatic cystic neoplasms (mPCN). In this study, we aimed to evaluate and compare the clinically utility of the Sendai-06, Fukuoka-12, Fukuoka-17 and European-18 guidelines in predicting malignancy of mPCN.

METHODS

One hundred and eighty-eight patients with mucinous cystic neoplasms (MCN) or intraductal papillary mucinous neoplasm (IPMN) who underwent surgery were retrospectively reviewed and classified under the 4 guidelines. Malignancy was defined as high grade dysplasia and invasive carcinoma.

RESULTS

Raised CA19-9>37U/ml, enhancing mural nodule≥5 mm and main pancreatic duct≥10 mm were significantly associated with malignancy on multivariate analysis. Increasing number of high risk features, absolute indications (European-18), worrisome risk or relative indications (European-18) were significantly associated with an increased likelihood of malignancy. The positive predictive values (PPV) of high risk features for Sendai-06, Fukuoka-12, Fukuoka-17 and absolute indications (European-18) for malignancy were 53%, 76%, 78% and 78% respectively. The negative predictive values (NPV) of the Sendai-06, Fukuoka-12 and Fukuoka-17 were 100%, while that of the European-18 was 92%. Risk of malignancy for patients with ≥4 worrisome features (Fukuoka-17) and ≥3 relative indications (European-18) was 66.7% and 75.0% respectively.

CONCLUSIONS

All 4 guidelines studied were useful in the initial triage of mPCN for the risk stratification of malignancy. The Fukuoka-17 had the highest PPV and NPV.

Intracholecystic tubular non-mucinous neoplasm (ICTN) of the gallbladder: a clinicopathologically distinct, invasion-resistant entity

Preinvasive tumor-forming gallbladder neoplasms that are composed of small, non-mucinous tubules with complex architecture remain a poorly characterized group. Here, we evaluated the clinicopathological characteristics of this entity. Twenty-eight examples were analyzed. Tumors were invariably pedunculated polyps with thin stalks, often presented as loosely attached intraluminal nodules, with cauliflower architecture (akin to cholesterol polyps) comprised of compact, back-to-back acinar-like, small tubular units with minimal/no cytoplasm showing variable complexity, creating a picture distinct from the other tubular type dysplasia in the gallbladder. Their limited stroma showed distinctive amorphous amyloid-like hyalinization (39%). While some had round nuclei with single prominent nucleoli, others exhibited slightly more elongated nuclei with washed out chromatin reminiscent of papillary thyroid carcinoma. Squamoid/meningothelial-like morules (71%) and subtle neuroendocrine cell clusters (39%) were frequent. The level of cytoarchitectural atypia qualified as high-grade dysplasia (HGD) in all cases, but none were invasive. The background mucosa showed no dysplasia, but cholesterolosis. The majority (n = 8/12) showed diffuse MUC6 expression and lacked MUC5AC expression. Based on these observations, 635 gallbladder carcinomas were re-analyzed for residual/adjacent lesions with entity-defining characteristics disclosed here, and none could be identified. Preinvasive tubular non-mucinous neoplasm of the gallbladder, which we propose to classify as intracholecystic tubular non-mucinous neoplasm, is a clinicopathologically discrete entity, which tends to occur in uninjured gallbladders and in association with cholesterol polyps. By being tubular, non-mucinous and MUC6-positive, it is akin to intraductal tubulopapillary neoplasms of pancreatobiliary tract, but it is also different in many other aspects. Although their cytoarchitectural complexity warrants an HGD/carcinoma classification, they do not show invasion and their distinct characteristics warrant their separate classification.

Use of Biomarkers and Imaging for Early Detection of Pancreatic Cancer

Pancreatic cancer remains one of the deadliest cancers worldwide, and it is typically diagnosed late, with a poor prognosis. Early detection is the most important underlying factor for improving the prognosis of pancreatic cancer patients. One of the most effective strategies for detecting cancers at an early stage is screening of the general population. However, because of the low incidence of pancreatic cancer in the general population, the stratification of subjects who need to undergo further examinations by invasive and expensive modalities is important. Therefore, minimally invasive modalities involving biomarkers and imaging techniques that would facilitate the early detection of pancreatic cancer are highly needed. Multiple types of new blood biomarkers have recently been developed, including unique post-translational modifications of circulating proteins, circulating exosomes, microRNAs, and circulating tumor DNA. We previously reported that circulating apolipoprotein A2 undergoes unique processing in the bloodstream of patients with pancreatic cancer and its precancerous lesions. Additionally, we recently demonstrated a new method for measuring pancreatic proton density in the fat fraction using a fat–water magnetic resonance imaging technique that reflects pancreatic steatosis. In this review, we describe recent developments in potential biomarkers and imaging modalities for the early detection and risk stratification of pancreatic cancer, and we discuss current strategies for implementing screening programs for pancreatic cancer.

Pancreatic Ductal Adenocarcinoma and Its Variants: Pearls and Perils

Pancreatic ductal adenocarcinoma (PDAC), an epithelial neoplasm derived from the pancreatic ductal tree, is the most common histologic type of pancreatic cancer and accounts for 85%-95% of all solid pancreatic tumors. As a highly lethal malignancy, it is the seventh leading cause of cancer death worldwide and is responsible for more than 300 000 deaths per year. PDAC is highly resistant to current therapies, affording patients a 5-year overall survival rate of only 7.2%. It is characterized histologically by its highly desmoplastic stroma embedding tubular and ductlike structures. On images, it typically manifests as a poorly defined hypoenhancing mass, causing ductal obstruction and vascular involvement. Little is known about the other histologic subtypes of PDAC, mainly because of their rarity and lack of specific patterns of disease manifestation. According to the World Health Organization, these variants include adenosquamous carcinoma, colloid carcinoma, hepatoid carcinoma, medullary carcinoma, signet ring cell carcinoma, undifferentiated carcinoma with osteoclast-like giant cells, and undifferentiated carcinoma. Depending on the subtype, they can confer a better or even worse prognosis than that of conventional PDAC. Thus, awareness of the existence and differentiation of these variants on the basis of imaging and histopathologic characteristics is crucial to guide clinical decision making for optimal treatment and patient management.

Can contrast-enhanced harmonic endoscopic ultrasonography accurately diagnose main pancreatic duct involvement in intraductal papillary mucinous neoplasms?

BACKGROUND

Main pancreatic duct (MPD) involvement in branch duct-type intraductal papillary mucinous neoplasms (BD-IPMNs) is a high risk finding for malignant IPMNs. However, discrepancies exist in the identification of MPD involvement between imaging findings and pathological diagnosis. The purpose of this study was to evaluate the diagnostic accuracy of preoperative assessment of MPD involvement in IPMNs using contrast-enhanced harmonic endoscopic ultrasound (CH-EUS).

METHODS

This study involved 166 consecutive patients with BD-IPMNs who underwent surgical resection. CH-EUS was used to evaluate the MPD involvement according to the presence of mural nodules (MN) that advanced into the MPD or involved the MPD. The CH-EUS findings were compared with the pathological findings. Additionally, we analyzed the risk factors for malignant BD-IPMNs using multivariate analysis.

RESULTS

A total of 77, 51, and 38 patients were pathologically diagnosed with low-grade or intermediate-grade dysplasia, high-grade dysplasia and invasive IPMNs, respectively. MPD involvement was diagnosed using CH-EUS (MPD-inv.-EUS) in 90 (54.2%) patients with a sensitivity, specificity and accuracy of 83.5%, 87.0% and 84.9%, respectively. The malignancy rate in patients with MPD-inv.-EUS was 71.6% (63/90). Multivariate logistic regression analysis showed that MPD-inv.-EUS (OR, 3.61; 95% CI:1.45-8.98), age (OR, 5.70; 95% CI: 1.47-22.2), cyst size (OR, 2.45; 95% CI:1.04-5.78) and MN size (OR, 7.05; 95% CI:2.48-20.0) were significant for malignant BD-IPMNs.

CONCLUSIONS

MPD-inv.-EUS accurately represents the pathological involvement of IPMN and may be a useful predictor of malignant BD-IPMNs.

Pancreatic cancer triggers diabetes through TGF-β-mediated selective depletion of islet β-cells

Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease that remains incurable because of late diagnosis, which renders any therapeutic intervention challenging. Most PDAC patients develop de novo diabetes, which exacerbates their morbidity and mortality. How PDAC triggers diabetes is still unfolding. Using a mouse model of KrasG12D-driven PDAC, which faithfully recapitulates the progression of the human disease, we observed a massive and selective depletion of β-cells, occurring very early at the stages of preneoplastic lesions. Mechanistically, we found that increased TGF beta (TGF-β) signaling during PDAC progression caused erosion of β-cell mass through apoptosis. Suppressing TGF-β signaling, either pharmacologically through TGF-β immunoneutralization or genetically through deletion of Smad4 or TGF-β type II receptor (TβRII), afforded substantial protection against PDAC-driven β-cell depletion. From a translational perspective, both activation of TGF-β signaling and depletion of β-cells frequently occur in human PDAC, providing a mechanistic explanation for the pathogenesis of diabetes in PDAC patients, and further implicating new-onset diabetes as a potential early prognostic marker for PDAC.

Simple mucinous cysts of the pancreas have heterogeneous somatic mutations

Simple mucinous cysts of the pancreas have an epithelial lining resembling pancreatic intraepithelial neoplasia but may have a clinical presentation similar to premalignant mucinous neoplasms such as intraductal papillary mucinous neoplasms. Whether the epithelial lining shares genomic alterations with other pancreatic preinvasive neoplasms such as PanIN and intraductal papillary mucinous neoplasm has not been determined. We performed targeted sequencing analysis using a custom-designed MiSeq panel including the full coding regions of 18 pancreatic cancer genes on 13 clinically and pathologically well-characterized simple mucinous cysts. We detected 59 mutations in 15 genes in the cohort, with a median of 4 mutations per cyst (range = 0-16 mutations per cyst). The mutated genes and rate of detected mutations were as follows: KMT2C (MLL3) (62%), KRAS (15%), BRAF (8%), RNF43 (8%), CDKN2a (8%), TP53 (15%), and SMAD4 (8%). No GNAS mutations were detected. Four cases (31%) had no mutations detected. These findings place the majority of simple mucinous cysts of the pancreas in the spectrum of early, low-grade mucinous neoplasia, albeit with a different spectrum of genomic alterations compared with PanIN and intraductal papillary mucinous neoplasm.

Surgical Outcomes After Pancreatic Resection of Screening-Detected Lesions in Individuals at High Risk for Developing Pancreatic Cancer

BACKGROUND

Screening high-risk individuals (HRI) can detect potentially curable pancreatic ductal adenocarcinoma (PDAC) and its precursors. We describe the outcomes of high-risk individuals (HRI) after pancreatic resection of screen-detected neoplasms.

METHODS

Asymptomatic HRI enrolled in the prospective Cancer of the Pancreas Screening (CAPS) studies from 1998 to 2014 based on family history or germline mutations undergoing surveillance for at least 6 months were included. Pathologic diagnoses, hospital length of stay, incidence of diabetes mellitus, operative morbidity, need for repeat operation, and disease-specific mortality were determined.

RESULTS

Among 354 HRI, 48 (13.6%) had 57 operations (distal pancreatectomy (31), Whipple (20), and total pancreatectomy (6)) for suspected pancreatic neoplasms presenting as a solid mass (22), cystic lesion(s) (25), or duct stricture (1). The median length of stay was 7 days (IQR 5-11). Nine of the 42 HRI underwent completion pancreatectomy for a new lesion after a median of 3.8 years (IQR 2.5-7.6). Postoperative complications developed in 17 HRI (35%); there were no perioperative deaths. New-onset diabetes mellitus after partial resection developed in 20% of HRI. Fourteen PDACs were diagnosed, 11 were screen-detected, 10 were resectable, and 9 had an R0 resection. Metachronous PDAC developed in remnant pancreata of 2 HRI. PDAC-related mortality was 4/10 (40%), with 90% 1-year survival and 60% 5-year survival, respectively.

CONCLUSIONS

Screening HRI can detect PDAC with a high resectability rate. Surgical treatment is associated with a relatively short length of stay and low readmission rate, acceptable morbidity, zero 90-day mortality, and significant long-term survival.

CLINICAL TRIAL REGISTRATION NUMBER

NCT2000089.

Proteostasis Dysregulation in Pancreatic Cancer

The most common form of pancreatic cancer, pancreatic ductal adenocarcinoma (PDAC), has a dismal 5-year survival rate of less than 5%. Radical surgical resection, in combination with adjuvant chemotherapy, provides the best option for long-term patient survival. However, only approximately 20% of patients are resectable at the time of diagnosis, due to locally advanced or metastatic disease. There is an urgent need for the identification of new, specific, and more sensitive biomarkers for diagnosis, prognosis, and prediction to improve the treatment options for pancreatic cancer patients. Dysregulation of proteostasis is linked to many pathophysiological conditions, including various types of cancer. In this review, we report on findings relating to the main cellular protein degradation systems, the ubiquitin-proteasome system (UPS) and autophagy, in pancreatic cancer. The expression of several components of the proteolytic network, including E3 ubiquitin-ligases and deubiquitinating enzymes, are dysregulated in PDAC, which accounts for approximately 90% of all pancreatic malignancies. In the future, a deeper understanding of the emerging role of proteostasis in pancreatic cancer has the potential to provide clinically relevant biomarkers and new strategies for combinatorial therapeutic options to better help treat the patients.

Pancreatic Cancer Molecular Classifications: From Bulk Genomics to Single Cell Analysis

Pancreatic cancer represents one of the most lethal disease worldwide but still orphan of a molecularly driven therapeutic approach, although many genomic and transcriptomic classifications have been proposed over the years. Clinical heterogeneity is a hallmark of this disease, as different patients show different responses to the same therapeutic regimens. However, genomic analyses revealed quite a homogeneous disease picture, with very common mutations in four genes only (KRAS, TP53, CDKN2A, and SMAD4) and a long tail of other mutated genes, with doubtful pathogenic meaning. Even bulk transcriptomic classifications could not resolve this great heterogeneity, as many informations related to small cell populations within cancer tissue could be lost. At the same time, single cell analysis has emerged as a powerful tool to dissect intratumoral heterogeneity like never before, with possibility of generating a new disease taxonomy at unprecedented molecular resolution. In this review, we summarize the most relevant genomic, bulk and single-cell transcriptomic classifications of pancreatic cancer, and try to understand how novel technologies, like single cell analysis, could lead to novel therapeutic strategies for this highly lethal disease.

Multiple Carcinomas and Intraepithelial Neoplasms in a Case of Familial Pancreatic Cancer: Rapid Morphological Changes in the Pancreatic Cyst and Pathological Lesions Undetected by Clinical Images

A 69-year-old woman with a family history of pancreatic cancer was referred because of imaging changes of a pancreas cyst. Magnetic resonance cholangiopancreatography showed a faintly dilated main pancreatic duct and a pancreas body cyst that had changed rapidly over the past year. Computed tomography demonstrated an emerging enhancing lesion in the pancreatic cyst. Endoscopic ultrasonography revealed an irregular-margined, heterogeneous-echoic pancreatic mass, without findings of early chronic pancreatitis. She underwent distal pancreatectomy. A histologic examination of the resected specimen revealed invasive adenocarcinoma with numerous multicentric foci of pancreatic intraepithelial neoplasia (PanIN), including high-grade PanIN, apparently separate from the main cancer.

Evolution of the immune landscape during progression of pancreatic intraductal papillary mucinous neoplasms to invasive cancer

BACKGROUND

Intraductal papillary mucinous neoplasms (IPMNs) are precursor lesions of pancreatic cancer, which is characterized by an immunosuppressive microenvironment. Yet, the spatial distribution of the immune infiltrate and how it changes during IPMN progression is just beginning to be understood.

METHODS

We obtained tissue samples from patients who underwent pancreatic surgery for IPMN, and performed comprehensive immunohistochemical analyses to investigate the clinical significance, composition and spatial organization of the immune microenvironment during progression of IPMNs. Survival analysis of pancreatic cancer patients was stratified by tumour infiltrating immune cell subtypes.

FINDINGS

The immune microenvironment evolves from a diverse T cell mixture, comprising CD8⁺ T cells, Th/c1 and Th/c2 as major players combined with Th9, Th/c17, Th22, and Treg cells in low-grade IPMN, to a Treg dominated immunosuppressive state in invasive pancreatic cancer. Organized lymphoid clusters formed in IPMN surrounding stroma and accumulated immunosuppressive cell types during tumour progression. Survival of pancreatic cancer patients correlated with Th2 signatures in the tumour microenvironment.

INTERPRETATION

The major change with regards to T cell composition during IPMN progression occurs at the step of tissue invasion, indicating that malignant transformation only occurs when tumour immune surveillance is overcome. This suggests that novel immunotherapies that would boost spontaneous antitumor immunity at premalignant states could prevent pancreatic cancer development.

FUNDING

The present work was supported by German Cancer Aid grants (70,112,720 and 70,113,167) to S. R., and the Olympia Morata Programme of the Medical Faculty of Heidelberg University to S. R.

Risk Factors for Pancreatic Cancer and the Necessity of Long-Term Surveillance in Patients With Pancreatic Cystic Lesions

OBJECTIVES

Pancreatic cystic lesions (PCLs) are a risk factor for pancreatic cancer (PC). Which PCLs should be surveilled and necessity of long-term observation are still controversial.

METHODS

From January 2000 to March 2016, we enrolled 1137 patients with PCLs observed for 1 year. We defined PCLs with cyst size of greater than 30 mm, main pancreatic duct (MPD) of greater than 5 mm or mural nodule as high-risk group, and others as low-risk group (LRG). Kaplan-Meier method and Cox proportional hazard model were applied to assess incidence and risk factors of PC.

RESULTS

In 107 high-risk group and 1030 LRG patients, mean observation period was 4.3 years and 5.0 years, respectively, and 5-year PC incidence was 12.0% and 2.8%, respectively. In LRG, MPD of greater than 3 mm, diabetes mellitus, and presumed branch-duct intraductal papillary mucinous neoplasia (BD-IPMN), defined as PCLs fulfilling any of multilocular formation, multiplicity, or MPD communication, were independent risk factors for PC. In 450 LRG observed for 5 years, 10-year PC incidence was higher in PCLs with our identified risk factors. There was no PC occurrence in PCLs not presumed BD-IPMN after 5-year observation.

CONCLUSIONS

Continuous surveillance is needed after 5-year observation, especially in LRG with our identified risk factors. For discontinuing surveillance, PCLs not presumed BD-IPMN at fifth year could be candidates.

Exosomal glypican-1 for risk stratification of pancreatic cystic lesions: A case of pathological progression in the absence of any suspicious imaging finding

The clinical management of patients with pancreatic cystic lesions is of utmost importance to identify those at high risk for pathological progression. Current recommendations are guided by clinical presentation and radiologic criteria, but the results fall short for a disease that the only curative option is surgical resection. There is an urgent need for the introduction of biomarkers that can help in risk assessment of such lesions. We report a case of a pancreatic cystic lesion without imagiological findings suggestive of advanced disease, and high levels of a circulating biomarker, glypican-1 (GPC-1), which parallel those of patients with pancreatic cancer. One year after, the patient revealed malignant progression at follow-up. Our report is unprecedented in the literature. It describes a clinical case in which a biomarker was positive for a patient that only showed progression one year after its detection. This clinical information goes beyond the current knowledge in the field because it shows that the introduction of liquid biopsy and biomarkers is a highly promising clinical tool for the non-invasive assessment of pancreatic cancer precursor lesions, ultimately increasing the rate of patients eligible for surgical resection.

Clinical significance of promoter methylation status of tumor suppressor genes in circulating DNA of pancreatic cancer patients

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is a very aggressive cancer. There are various sub-cellular events (both genetic and epigenetic) that get dysregulated leading to tumorigenesis. Methylation in promoters of tumor suppressor genes is one of these epigenetic phenomena contributing to the pathogenesis of cancer. Genes analyzed for promoter methylation status in this study namely SPARC (Secreted Protein Acidic and Rich in Cysteine, UCHL1 (ubiquitin carboxy-terminal hydrolase L1), NPTX2 (neuronal pentraxin 2), PENK (proenkephalin) had been studied in pancreatic cancer, but there is a need to check methylation in these genes as circulatory non-invasive markers. This study analyzed the absolute quantification of methylation levels of SPARC, UCHL1, PENK, and NPTX2 genes promoters in PDAC patients as well as in chronic pancreatitis (CP) patients and healthy subjects (HC) and evaluated its clinical significance in PDAC.

MATERIALS AND METHODS

The study included 65 PDAC patients, 25 CP patients, and 25 healthy controls. DNA was extracted from their plasma samples and subsequently given bisulfite treatment. Absolute quantization of methylated and unmethylated copies of gene promoters of all the four genes was performed using real-time PCR (SYBR green) by the standard curve method. Methylation levels were expressed as methylation index (MI) for each gene in each patient. MI was calculated from absolute copy numbers as follows: MI-methylated copy number/methylated copy number + unmethylated copy number). These indices were used to compare gene methylation levels within different groups and to correlate with clinicopathological features and survival of pancreatic cancer patients. An appropriate statistical analysis was applied.

RESULTS

Methylation indices for all the four genes in PDAC cases were found to be significantly higher as compared to that in healthy individuals. SPARC MI values were found to differentiate early-stage PDAC patients from CP patients. PDAC patients with the metastasized disease and stage IV disease were found to have high MI for the SPARC gene as well as for the NPTX2 gene, while a higher UCHL1 methylation index was found to correlate with an advanced stage of the disease. Higher MI values for SPARC and NPTX2 genes were found to associate with poor survival in patients with PDAC.

CONCLUSION

Methylation load in the form of MI for each of the four genes assessed in plasma may emerge as a non-invasive biomarker to differentiate pancreatic cancer from healthy individuals. But only SPARC and NPTX2 hypermethylation were able to distinguish pancreatic cancer from chronic pancreatitis. Association of aberrant methylation in SPARC and NPTX2 gene with metastasis and poor survival of patients suggest the role of methylation in these genes as prognostic markers.

Intraductal Oncocytic Papillary Neoplasms: Clinical-Pathologic Characterization of 24 Cases, With An Emphasis on Associated Invasive Carcinomas

BACKGROUND

Intraductal oncocytic papillary neoplasm (IOPN) of the pancreas is a rare tumor. Recent molecular data indicate that it is distinct from other intraductal neoplasms; however, its clinicopathologic characteristics, especially the frequency/significance of an invasive carcinoma component, and biologic behavior remain to be fully defined.

DESIGN

Clinicopathologic characteristics and survival of 24 IOPNs were analyzed. By definition, all tumors exhibited intraductal growth and oncocytic morphology.

RESULTS

The female:male ratio was 1.7, and mean age was 59. In 44% of the patients, the IOPN was discovered incidentally; however, the working diagnosis was "ductal adenocarcinoma" in 42%. Fourteen IOPNs occurred in the head of the pancreas. The median tumor size was 4.5 cm. The tumors often grew along adjacent benign ducts, mimicking invasion, but only 29% exhibited unequivocal invasive carcinoma, mostly in the form of microscopic foci (pT1a=4, pT1b=1, pT2=2), and only 6% had lymph node metastasis. Invasive carcinoma was predominantly composed of small tubular units lined by oncocytic cells, or individual oncocytic cells infiltrating the periductal stroma. Follow-up information was available for 18 patients (median=6.8 y). No patients died from the disease, and the overall 10-year survival was 94%. Patients with invasive carcinoma trended toward a lower 5-year recurrence-free survival than those with noninvasive IOPNs (66% vs. 93%, P=0.066), but overall survival was not impacted by the presence of invasion (P=0.38).

CONCLUSIONS

IOPN is a distinct tumor type in the pancreas. Despite its morphologic complexity and often extensive pagetoid spread to adjacent ducts, conventional invasive carcinoma is seen in only 29% and usually as microscopic foci. Thus, it is not surprising that IOPN exhibits indolent behavior even when invasion is present.

Pitfalls in the MDCT of pancreatic cancer: strategies for minimizing errors

Multidetector computed tomography (MDCT) is a widely used cross-sectional imaging modality for initial evaluation of patients with suspected pancreatic ductal adenocarcinoma (PDAC). However, diagnosis of PDAC can be challenging due to numerous pitfalls associated with image acquisition and interpretation, including technical factors, imaging features, and cognitive errors. Accurate diagnosis requires familiarity with these pitfalls, as these can be minimized using systematic strategies. Suboptimal acquisition protocols and other technical errors such as motion artifacts and incomplete anatomical coverage increase the risk of misdiagnosis. Interpretation of images can be challenging due to intrinsic tumor features (including small and isoenhancing masses, exophytic masses, subtle pancreatic duct irregularities, and diffuse tumor infiltration), presence of coexisting pathology (including chronic pancreatitis and intraductal papillary mucinous neoplasm), mimickers of PDAC (including focal fatty infiltration and focal pancreatitis), distracting findings, and satisfaction of search. Awareness of pitfalls associated with the diagnosis of PDAC along with the strategies to avoid them will help radiologists to minimize technical and interpretation errors. Cognizance and mitigation of these errors can lead to earlier PDAC diagnosis and ultimately improve patient prognosis.

Progress in Animal Models of Pancreatic Ductal Adenocarcinoma

As a common gastrointestinal tumor, the incidence of pancreatic cancer has been increasing in recent years. The disease shows multi-gene, multi-step complex evolution from occurrence to dissemination. Furthermore, pancreatic cancer has an insidious onset and an extremely poor prognosis, so it is difficult to obtain cinical specimens at different stages of the disease, and it is, therefore, difficult to observe tumorigenesis and tumor development in patients with pancreatic cancer. At present, no standard protocols stipulate clinical treatment of pancreatic cancer, and the benefit rate of new targeted therapies is low. For this reason, a well-established preclinical model of pancreatic cancer must be established to allow further exploration of the occurrence, development, invasion, and metastasis mechanism of pancreatic cancer, as well as to facilitate research into new therapeutic targets. A large number of animal models of pancreatic cancer are currently available, including a cancer cell line-based xenograft, a patient-derived xenograft, several mouse models (including transgenic mice), and organoid models. These models have their own characteristics, but they still cannot perfectly predict the clinical outcome of the new treatment. In this paper, we present the distinctive features of the currently popular pancreatic cancer models, and discuss their preparation methods, clinical relations, scientific purposes and limitations.

From somatic mutation to early detection: insights from molecular characterization of pancreatic cancer precursor lesions

Pancreatic cancer arises from noninvasive precursor lesions, including pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasm (IPMN), and mucinous cystic neoplasm (MCN), which are curable if detected early enough. Recently, these types of precursor lesions have been extensively characterized at the molecular level, defining the timing of critical genetic alterations in tumorigenesis pathways. The results of these studies deepen our understanding of tumorigenesis in the pancreas, providing novel insights into tumor initiation and progression. Perhaps more importantly, they also provide a rational foundation for early detection approaches that could allow clinical intervention prior to malignant transformation. In this review, we summarize the results of comprehensive molecular characterization of PanINs, IPMNs, and MCNs and discuss the implications for cancer biology as well as early detection. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Intraductal papillary mucinous neoplasm (IPMN) of the pancreas: clinicopathological features and long-term outcomes following a pancreatectomy

OBJECTIVE

the objective of this study was to analyze the anatomical and clinical features and long-term oncologic outcomes of 25 patients that underwent surgery due to intraductal papillary mucinous neoplasm of the pancreas.

MATERIAL AND METHODS

patients undergoing surgery for intraductal papillary mucinous neoplasm of the pancreas were identified from a prospective database of pancreatic resections. Demographic data, symptoms, type of surgery and type of lesion (branch type, main duct or mixed) were recorded. The lesions were classified into invasive (high grade dysplasia and carcinoma) and noninvasive (low- or intermediate-grade dysplasia). Postoperative complications were analyzed as well as the pattern of recurrence and disease-free survival at five and ten years.

RESULTS

the most common symptoms in the 25 patients (14 males and eleven females) were abdominal pain and weight loss. Eight (32%) cases were diagnosed incidentally. Twelve (48%) of the lesions were of the branch type, three affected the main duct and ten (40%) were mixed. Twelve cephalic duodenopancreatectomies and seven total pancreatectomies were performed; three were central; two, distal; and one, enucleation. Seven cases (32%) had an invasive phenotype. Three patients had locoregional and distant recurrence at six, 16 and 46 months after surgery with a median follow-up of 7.7 years. Disease-free survival at five and ten years for the noninvasive type was 94% and 57% for invasive phenotypes (p < 0.05).

CONCLUSIONS

intraductal papillary mucinous neoplasm is a heterogeneous entity with well differentiated phenotypes, which requires a tailored strategy and treatment, as established in the current consensus guidelines due to its malignant potential.

Accuracy of an administrative database for pancreatic cancer by international classification of disease 10th codes: A retrospective large-cohort study

BACKGROUND

Korean National Health Insurance (NHI) claims database provides large-cohort. However, studies regarding accuracy of administrative database for pancreatic cancer (PC) have not been reported. We aimed to identify accuracy of NHI database regarding PC classified by international classification of disease (ICD)-10 codes.

AIM

To identify the accuracy and usefulness of administrative database in PC and the accurate ICD codes for PC with location.

METHODS

Study and control groups were collected from 2003 to 2016 at Seoul National University Bundang Hospital. Cases of PC were identified in NHI database by international classification of diseases, 10th revision edition (ICD-10 codes) supported with V codes. V code is issued by medical doctors for covering 95% of medical cost by Korean government. According to pathologic reports, definite or possible diagnoses were defined using medical records, images, and pathology.

RESULTS

A total of 1846 cases with PC and controls were collected. Among PC, only 410 (22.2%) cases were identified as specific cancer sites including head in 234 (12.7%) cases, tail in 104 (5.6%) cases and body in 72 (3.9%) cases. Among PC, 910 (49.3%) cases were diagnosed by definite criteria. Most of these were adenocarcinoma (98.0%). The rates of definite diagnosis of PC were highest in head (70.1%) followed by body (47.2%) and tail (43.3%). False-positive cases were pancreatic cystic neoplasm and metastasis to the pancreas. In terms of the overall diagnosis of PC, sensitivity, specificity, positive predictive value, and negative predictive value were 99.95%, 98.72%, 98.70%, and 99.95%, respectively. Diagnostic accuracy was similar both in terms of diagnostic criteria and tumor locations.

CONCLUSION

Korean NHI claims database collected according to ICD-10 code with V code for PC showed good accuracy.

Intra-Ampullary Papillary-Tubular Neoplasm: A Population-Based Analysis

Background

Intra-ampullary papillary-tubular neoplasm (IAPN) is recognized as a precancerous lesion with a great tendency to evolve into pancreatic cancer. The Surveillance, Epidemiology, and End Results (SEER) database is now large enough to study unusual cancers. Based on pathologic and epidemiologic characteristics of IAPN available in SEER, important clinicopathological correlations can be made.

Material/Methods

Cases of IAPN and other intraductal papillary mucinous neoplasms of the bile duct (OBIPMN) diagnosed between 1973 and 2014 were searched in the SEER database. The analysis was carried out with respect to patient clinical characteristics, tumor characteristics, incidence, and survival.

Results

In total, 685 patients with IAPN were identified compared with 2465 patients with OBIPMN in the same period. The incidence rate of IAPN was decreased, with a 4.882% annual percent change. The patient characteristics of IAPN were quite different from OBIPMN in many characteristics, including age, gender, marital status, and survival. Compared with OBIPMN, the tumor characteristics of IAPN indicated that more patients were diagnosed at an earlier stage in multiple stage systems such as pathological grade (P<0.001), sixth American Joint Committee on Cancer stage (P<0.001), TNM stage (P<0.001), and SEER historic stage (P<0.001). In the survival analysis, the cancer-specific survival of IAPN was significantly better than OBIPMN (P<0.001) and the cancer-specific survival get worse at higher stages (P<0.001). Moreover, the 5-year cancer-specific survival rate of IAPN was also significantly better than that of OBIPMN (36.5% versus 25.4%, P<0.001). Finally, the multivariate analysis showed a correlation between cancer-specific survival and age of diagnosis and N stage (P<0.001).

Conclusions

Analysis of the SEER database clearly demonstrated that IAPN was a precancerous lesion tend to be diagnosed earlier compared with OBIPMN, which contributed to the better prognosis, and surgery was suggested if possible.

Multi-institutional Validation Study of Pancreatic Cyst Fluid Protein Analysis for Prediction of High-risk Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE

Preliminary work by our group suggested that proteins within the pancreatic cyst fluid (CF) may discriminate degree of IPMN dysplasia. We sought to externally validate these markers and determine whether their inclusion in a preoperative clinical nomogram could increase diagnostic accuracy.

SUMMARY BACKGROUND DATA

IPMN is the most common radiographically identifiable precursor to pancreatic cancer; however, the timing and frequency of its malignant progression are unknown, and there are currently no reliable preoperative tests that can determine the grade of dysplasia in IPMN.

METHODS

Clinical and radiographic data, as well as CF samples, were obtained from 149 patients who underwent resection for IPMN at 1 of 3 institutions. High-risk disease was defined as the presence of high-grade dysplasia or invasive carcinoma. Multianalyte bead array analysis (Luminex) of CF was performed for 4 protein markers that were previously associated with high-risk disease. Logistic regression models were fit on training data, with and without adjustment for a previously developed clinical nomogram and validated with an external testing set. The models incorporating clinical risk score were presented graphically as nomograms.

RESULTS

Within the group of 149 resected patients, 89 (60%) had low-risk disease, and 60 (40%) had high-risk disease. All 4 CF markers (MMP9, CA72-4, sFASL, and IL-4) were overexpressed in patients with high-risk IPMN (P < 0.05). Two predictive models based on preselected combinations of CF markers had concordance indices of 0.76 (Model-1) and 0.80 (Model-2). Integration of each CF marker model into a previously described clinical nomogram leads to increased discrimination compared with either the CF models or nomogram alone (c-indices of 0.84 and 0.83, respectively).

CONCLUSIONS

This multi-institutional study validated 2 CF protein marker models for preoperative identification of high-risk IPMN. When combined with a clinical nomogram, the ability to predict high-grade dysplasia was even stronger.

Combination Therapies and Drug Delivery Platforms in Combating Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC), the fourth leading cause of cancer-related death in the United States, is highly aggressive and resistant to both chemo- and radiotherapy. It remains one of the most difficult-to-treat cancers, not only due to its unique pathobiological features such as stroma-rich desmoplastic tumors surrounded by hypovascular and hypoperfused vessels limiting the transport of therapeutic agents, but also due to problematic early detection, which renders most treatment options largely ineffective, resulting in extensive metastasis. To elevate therapeutic effectiveness of treatments and overt their toxicity, significant enthusiasm was generated to exploit new strategies for combating PDAC. Combination therapy targeting different barriers to mitigate delivery issues and reduce tumor recurrence and metastasis has demonstrated optimal outcomes in patients' survival and quality of life, providing possible approaches to overcome therapeutic challenges. This paper aims to provide an overview of currently explored multimodal therapies using either conventional therapy or nanomedicines along with rationale, up-to-date progress, as well as the key challenges that must be overcome. Understanding the future directions of the field may assist in the successful development of novel treatment strategies for enhancing therapeutic efficacy in PDAC.

Mutational Patterns in Pancreatic Juice of Intraductal Papillary Mucinous Neoplasms and Concomitant Pancreatic Cancer

OBJECTIVES

The aims of this study were to identify genetic characteristics of intraductal papillary mucinous neoplasm (IPMN)-associated pancreatic ductal carcinoma (PDC) and to detect these markers using pancreatic juice.

METHODS

From 76 cases, 102 tissues were obtained: 29 cases were noninvasive IPMN, 18 were PDC derived from IPMN (D-PDC; noninvasive part, n = 16; invasive part, n = 18), and 29 were PDC concomitant with IPMN (C-PDC; IPMN part, n = 10; PDC part, n = 29). Moreover, pancreatic juice samples from 28 cases were obtained (noninvasive IPMN, n = 13; D-PDC, n = 7; C-PDC, n = 8). Fifty-one cancer-related genes were analyzed by next-generation sequencing.

RESULTS

TP53 mutation rates in D-PDC, C-PDC, and noninvasive IPMN were 67%, 66%, and 10%, respectively. Moreover, KRAS mutational patterns between 2 simultaneous tumors differed in 1 (6.3%) of the 16 D-PDC cases and in 8 (80%) of the 10 C-PDC cases (P = 0.0006). TP53 or multiple KRAS mutations were detected using pancreatic juice more frequently in C-PDC cases than in noninvasive IPMN cases (75% and 23%, respectively, P = 0.03).

CONCLUSIONS

Multiple KRAS mutations along with TP53 mutation are genetic markers for C-PDC, which could be detected using pancreatic juice preoperatively.

Invasive intraductal papillary mucinous neoplasms of the pancreas: relationships between mural nodules detected on thin-section contrast-enhanced MDCT and invasive components

PURPOSE

To elucidate the relationships between mural nodules (MNs) and invasive components in patients with invasive intraductal papillary mucinous neoplasm (IPMN) on the basis of thin-section contrast-enhanced multidetector CT (CE-MDCT) and pathologic findings.

METHODS

This retrospective study included 28 patients with surgically confirmed invasive IPMN. Two radiologists independently evaluated the thin-section (1-mm section thickness, no overlap) triple-phase CE-MDCT images for MNs, invasive components, and the continuity between them using a five-point scale (confidence scores of 1-3 as negative, 4 and 5 as positive). Kappa statistic was used to evaluate interobserver agreement. The CE-MDCT findings were correlated with pathologic findings.

RESULTS

Interobserver agreement was good or excellent. MNs consisting of tumor cells were recognized in 12 (42.9%) of 28 patients with no discrepancy between the two radiologists. Invasive components were detected in 85.7% and 82.1% in the pancreatic parenchymal phase for radiologist 1 and 2, respectively, and recognized as hypoattenuating areas. Pathologic continuities between MNs and invasive components were confirmed in five (41.7%) of 12 patients with MNs and these were detected on CE-MDCT. When combined seven patients without continuities between MNs and invasive components and 16 patients without MNs, the invasive components pathologically derived from non-nodular low-height papillary epithelium in 23 (82.1%) of 28 patients.

CONCLUSIONS

The invasive components derived more often from low-height papillary epithelium without MN appearance on CE-MDCT than from MN. Careful attention should be paid to the existence of an invasive component even in the absence of an enhancing MN.

Age-related morphological changes in the pancreas and their association with pancreatic carcinogenesis

Age-related pathological changes in the pancreas have been unclear because they are often minor and nonspecific. However, recent studies have shown that they are closely related to various pathological conditions such as pancreatic cancer and diabetes mellitus. Knowledge of age-related changes is important to determine appropriate prevention, detection, and treatment strategies for various diseases observed in elderly patients. We present a review of the pathological age-related non-neoplastic changes in the exocrine pancreas such as pancreatic fatty replacement, lobulocentric pancreatic atrophy, pancreatic duct ectasia, and metaplasia of exocrine pancreas, as well as changes in islet cells. We have discussed common pancreatic neoplasms in elderly patients, such as pancreatic intraepithelial neoplasia (PanIN), intraductal papillary mucinous neoplasms (IPMNs), and pancreatic ductal adenocarcinoma (PDAC). Age-related pathological changes play a key role in pancreatic carcinogenesis via telomere dysfunction. Further studies are warranted to clarify molecular mechanisms of pancreatic carcinogenesis in elderly patients.

Differential Cell Susceptibilities to KrasG12D in the Setting of Obstructive Chronic Pancreatitis

BACKGROUND & AIMS

Activating mutation of the KRAS gene is common in some cancers, such as pancreatic cancer, but rare in other cancers. Chronic pancreatitis is a predisposing condition for pancreatic ductal adenocarcinoma (PDAC), but how it synergizes with KRAS mutation is not known.

METHODS

We used a mouse model to express an activating mutation of Kras in conjunction with obstruction of the main pancreatic duct to recapitulate a common etiology of human chronic pancreatitis. Because the cell of origin of PDAC is not clear, Kras mutation was introduced into either duct cells or acinar cells.

RESULTS

Although KrasG12D expression in both cell types was protective against damage-associated cell death, chronic pancreatitis induced p53, p21, and growth arrest only in acinar-derived cells. Mutant duct cells did not elevate p53 or p21 expression and exhibited increased proliferation driving the appearance of PDAC over time.

CONCLUSIONS

One mechanism by which tissues may be susceptible or resistant to KRASG12D-initiated tumorigenesis is whether they undergo a p53-mediated damage response. In summary, we have uncovered a mechanism by which inflammation and intrinsic cellular programming synergize for the development of PDAC.

Genomic analysis of pancreatic juice DNA assesses malignant risk of intraductal papillary mucinous neoplasm of pancreas

Intraductal papillary mucinous neoplasm (IPMN) of pancreas has a high risk to develop into invasive cancer or co‐occur with malignant lesion. Therefore, it is important to assess its malignant risk by less‐invasive approach. Pancreatic juice cell‐free DNA (PJD) would be an ideal material in this purpose, but genetic biomarkers for predicting malignant risk from PJD are not yet established. We here performed deep exome sequencing analysis of PJD from 39 IPMN patients with or without malignant lesion. Somatic alterations and copy number alterations (CNAs) detected in PJD were compared with the histologic grade of IPMN to evaluate their potential as a malignancy marker. Somatic mutations of KRAS, GNAS, TP53, and RNF43 were commonly detected in PJD of IPMNs, but no association with the histologic grades of IPMN was found. Instead, mutation burden was positively correlated with the histologic grade (r = 0.427, P = 0.015). We also observed frequent copy number deletions in 17p13 (TP53) and amplifications in 7q21 and 8q24 (MYC) in PJDs. The amplifications in 7q21 and 8q24 were positively correlated with the histologic grade and most prevalent in the cases of invasive carcinoma (P = 0.002 and 7/11; P = 0.011 and 6/11, respectively). We concluded that mutation burden and CNAs detected in PJD may have potential to assess the malignant progression risk of IPMNs.

Somatic molecular analysis augments cytologic evaluation of pancreatic cyst fluids as a diagnostic tool

Objective: Better tools are needed for early diagnosis and classification of pancreatic cystic lesions (PCL) to trigger intervention before neoplastic precursor lesions progress to adenocarcinoma. We evaluated the capacity of molecular analysis to improve the accuracy of cytologic diagnosis for PCL with an emphasis on non-diagnostic/negative specimens. Design: In a span of 7 years, at a tertiary care hospital, 318 PCL endoscopic ultrasound-guided fine needle aspirations (EUS-FNA) were evaluated by cytologic examination and molecular analysis. Mucinous PCL were identified based on a clinical algorithm and 46 surgical resections were used to verify this approach. The mutation allele frequency (MAF) of commonly altered genes (BRAF, CDKN2A, CTNNB1, GNAS, RAS, PIK3CA, PTEN, SMAD4, TP53 and VHL) was evaluated for their ability to identify and grade mucinous PCL. Results: Cytology showed a diagnostic sensitivity of 43.5% for mucinous PCL due in part to the impact of non-diagnostic (28.8%) and negative (50.5%) specimens. Incorporating an algorithmic approach or molecular analysis markedly increased the accuracy of cytologic evaluation. Detection of mucinous PCL by molecular analysis was 93.3% based on the detection of KRAS and/or GNAS gene mutations (p = 0.0001). Additional genes provided a marginal improvement in sensitivity but were associated with cyst type (e.g. VHL) and grade (e.g. SMAD4). In the surgical cohort, molecular analysis and the proposed algorithm showed comparable sensitivity (88.9% vs. 100%). Conclusions: Incorporating somatic molecular analysis in the cytologic evaluation of EUS-FNA increases diagnostic accuracy for detection, classification and grading of PCL. This approach has the potential to improve patient management.

Subtyping of IPMN

Intraductal papillary mucinous neoplasms (IPMNs) characteristically consist of mucin-filled dilated ducts lined with neoplastic cells forming papillae with a diverse range of morphologies and varying grades of atypia. Based on morphological characteristics and immunohistochemical reaction against mucin proteins, IPMNs are classified into four distinct subtypes: gastric, intestinal, pancreatobiliary, and oncocytic. In this chapter, histomorphological criteria and techniques of immunohistochemical staining and its evaluation for subtyping IPMNs are described.

Non-branched microcysts of the pancreas on MR imaging of patients with pancreatic tumors who had pancreatectomy may predict the presence of pancreatic intraepithelial neoplasia (PanIN): a preliminary study

PURPOSE

To evaluate whether pancreatic parenchymal abnormalities on magnetic resonance imaging (MRI) are associated with pancreatic intraepithelial neoplasia (PanIN) on histology.

MATERIALS AND METHODS

Retrospective study approved by institutional review board. One hundred patients (48 men, 52 women; mean age, 53.2 ± 16.29 [SD]) underwent MRI before pancreatectomy for pancreatic tumors analyzed by two independent observers blinded to histopathological results for the presence of non-communicating microcysts and pancreatic atrophy (global or focal) beside tumors. MRI findings were compared to histopathological findings of resected specimens. Interobserver agreement was calculated. The association between parenchymal abnormalities and presence of PanIN was assessed by uni- and multivariate analyses.

RESULTS

PanIN was present in 65/100 patients (65%). The presence of microcysts on MRI had a sensitivity of 52.3% (34/65 [95%CI, 51.92-52.70%]), a specificity of 77.1% (27/35 [95%CI, 76.70-77.59]), and accuracy of 61% (61/100 95%CI [50.7-70.6]) for the diagnosis of PanIN while global atrophy had a sensitivity of 24.6% (16/6 [95%CI, 24.28-24.95]) and a specificity of 97.1% (34/35 [95%CI, 96.97-97.32%]). In multivariate analysis, the presence of microcysts (OR, 3.37 [95%CI, 1.3-8.76]) (p = 0.0127) and global atrophy (OR, 9.79 [95%CI, 1.21-79.129]) (p = 0.0324) were identified as independent predictors of the presence of PanIN. The combination of these two findings was observed in 10/65 PanIN patients and not in patients without PanIN (p = 0.013 with an OR of infinity [95%CI, 1.3-infinity]) and was not discriminant for PanIN-3 and lower grade (p = 0.22). Interobserver agreement for the presence of microcysts was excellent (kappa = 0.92), and for the presence of global atrophy, it was good (kappa = 0.73).

CONCLUSION

The presence of non-communicating microcysts on pre-operative MRI can be a significant predictor of PanIN in patients with pancreatic tumors.

KEY POINTS

• In patients with pancreatic tumors who had partial pancreatectomy, MR non-communicating pancreatic microcysts have a 52.3% sensitivity, a 77.1% specificity, and a 61% accuracy for the presence of PanIN with univariate and with an odds ratio of 3.37 with multivariate analyses. • The association of global atrophy and non-communicating microcysts increases the predictive risk of PanIN.

A Consensus Study of the Grading and Typing of Intraductal Papillary Mucinous Neoplasms of the Pancreas

OBJECTIVE

The grading and typing of intraductal papillary mucinous neoplasms (IPMNs) of the pancreas are challenging for pathologists. We aimed to clarify the points of consistency and disagreement in assessing the grades and types of IPMNs.

METHODS

Digital slide images of 20 IPMNs were independently assessed by 10 Japanese pathologists, who then held a consensus meeting to discuss the points of disagreement and develop a consensus and recommendations.

RESULTS

The average agreement rates for grade and type were 83.5% (range, 100%-40%) and 82.5% (range, 100%-50%) and the Fleiss' κ values were 0.567 and 0.636, respectively.

CONCLUSIONS

The disagreement points and recommendations were as follows: destructed ductal walls with desquamated neoplastic epithelia or mucin lakes partially lined with neoplastic cells could be invasion; intraductal stromal invasion could be dismissed unless vascular or lymphatic invasion existed; elastica staining may help visualize ducts in colloidal nodules; high-grade can be distinguished from low/intermediate grade by marked nuclear disarrangements and complex architecture in the intestinal papillae; oncocytic papillae are characterized by eosinophilic cells with round disoriented nuclei; high-grade gastric papillae can be distinguished from pancreatobiliary papillae by relatively low but complex architecture; and the most dysplastic papillae should be used to assess type in mixed papillae types.

Endoscopic ultrasound findings and pathological features of pancreatic carcinoma in situ

Background and study aims Few studies have evaluated detection of pancreatic carcinoma in situ (PCIS). We evaluated findings of endoscopic ultrasound (EUS) and pathological features of PCIS.

Patients and methods We histopathologically studied 16 patients with PCIS following EUS. Diagnostic features evaluated retrospectively included stricture of the main pancreatic duct (MPD) on EUS, presence or absence of hypoechoic areas surrounding the MPD stricture on EUS, the noncancerous part (pancreas of background) on EUS and histopathology, and histological findings adjacent to the area of PCIS.

Results On EUS, stricture of the MPD was found in 15 patients (93.8 %). Hypoechoic areas surrounding the MPD stricture were observed in 9 patients (56.3 %), including three (18.8 %) with a 10- to 11-mm hypoechoic mass. EUS findings of the noncancerous part indicated chronic pancreatitis in six patients (37.5 %), pancreatic fatty infiltration in seven (43.8 %), early chronic pancreatitis in two (12.5 %), and normal pancreas in one (6.3 %). Histological findings of the noncancerous part (proximal to the MPD stricture) indicated chronic pancreatitis in 13 patients (81.3 %) and pancreatic fatty infiltration in five patients (31.3 %). Histopathologically, subepithelial inflammatory cell infiltration and fibrosis were present in all 16 patients with PCIS.

Conclusions PCIS frequently causes localized changes in inflammation and fibrosis around the pancreatic duct. PCIS often accompanies chronic pancreatitis and pancreatic fatty infiltration in the background of the pancreas. EUS offers sufficient resolution to demonstrate pancreatic changes of PCIS.

Molecular subtypes of pancreatic cancer

Cancers that appear morphologically similar often have dramatically different clinical features, respond variably to therapy and have a range of outcomes. Compelling evidence now demonstrates that differences in the molecular pathology of otherwise indistinguishable cancers substantially impact the clinical characteristics of the disease. Molecular subtypes now guide preclinical and clinical therapeutic development and treatment in many cancer types. The ability to predict optimal therapeutic strategies ahead of treatment improves overall patient outcomes, minimizing treatment-related morbidity and cost. Although clinical decision making based on histopathological criteria underpinned by robust data is well established in many cancer types, subtypes of pancreatic cancer do not currently inform treatment decisions. However, accumulating molecular data are defining subgroups in pancreatic cancer with distinct biology and potential subtype-specific therapeutic vulnerabilities, providing the opportunity to define a de novo clinically applicable molecular taxonomy. This Review summarizes current knowledge concerning the molecular subtyping of pancreatic cancer and explores future strategies for using a molecular taxonomy to guide therapeutic development and ultimately routine therapy with the overall goal of improving outcomes for this disease.

Etiology and Risk Factors of Acute and Chronic Pancreatitis

Based on the recognition of common etiological and genetic risk factors, acute and chronic pancreatitis are increasingly regarded as a continuum of the same disease, with a significant overlap of clinical manifestations and phenotypes but distinct morphological and imaging appearances. Recent population-based and cohort studies have found that tobacco smoke conveys a greater risk than immoderate alcohol consumption for the development of chronic pancreatitis, and hypertriglyceridemia has been identified as a risk factor for acute pancreatitis - even when plasma levels are only mildly elevated. Hereditary pancreatitis, in its autosomal dominant form, is associated with mutations in the cationic trypsinogen gene (PRSS1), whereas a number of germline variations in other genes have been found to represent risk factors for chronic as well as acute pancreatitis. For now, most of these involve the pancreatic digestive protease/antiprotease system. Oftentimes, affected patients are burdened with multiple or accumulating risk factors, and genetic traits when combined with environmental toxins compound the chance of developing the disease. Determining the underlying etiology of pancreatitis is worth the effort since formerly intractable varieties such as autoimmune pancreatitis are now becoming increasingly treatable, and subtype-specific therapeutic modalities may become available.