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ObjectiveDespite improvements in imaging, serum CA19-9 and pathological evaluation, differentiating between benign and malignant bile duct strictures remains a diagnostic conundrum. Recent developments in next-generation sequencing (NGS) have opened new opportunities for early detection and management of cancers but, to date, have not been rigorously applied to biliary specimens.DesignWe prospectively evaluated a 28-gene NGS panel (BiliSeq) using endoscopic retrograde cholangiopancreatography-obtained biliary specimens from patients with bile duct strictures. The diagnostic performance of serum CA19-9, pathological evaluation and BiliSeq was assessed on 252 patients (57 trainings and 195 validations) with 346 biliary specimens.ResultsThe sensitivity and specificity of BiliSeq for malignant strictures was 73% and 100%, respectively. In comparison, an elevated serum CA19-9 and pathological evaluation had sensitivities of 76% and 48%, and specificities of 69% and 99%, respectively. The combination of BiliSeq and pathological evaluation increased the sensitivity to 83% and maintained a specificity of 99%. BiliSeq improved the sensitivity of pathological evaluation for malignancy from 35% to 77% for biliary brushings and from 52% to 83% for biliary biopsies. Among patients with primary sclerosing cholangitis (PSC), BiliSeq had an 83% sensitivity as compared with pathological evaluation with an 8% sensitivity. Therapeutically relevant genomic alterations were identified in 20 (8%) patients. Two patients withERBB2-amplified cholangiocarcinoma received a trastuzumab-based regimen and had measurable clinicoradiographic response.ConclusionsThe combination of BiliSeq and pathological evaluation of biliary specimens increased the detection of malignant strictures, particularly in patients with PSC. Additionally, BiliSeq identified alterations that may stratify patients for specific anticancer therapies.

Neoadjuvant therapy is increasingly used in localized pancreatic carcinoma, and survival is correlated with carbohydrate antigen 19-9 (CA19-9) levels and histopathologic response following neoadjuvant therapy. With several regimens now available, the choice of chemotherapy could be best dictated by response to neoadjuvant therapy (as measured by CA19-9 levels and/or pathologic response), a strategy defined herein as adaptive dynamic therapy.To evaluate the association of adaptive dynamic therapy with oncologic outcomes in patients with surgically resected pancreatic cancer.This retrospective cohort study included patients with localized pancreatic cancer who were treated with either gemcitabine/nab-paclitaxel or fluorouracil, leucovorin, irinotecan, and oxaliplatin (FOLFIRINOX) preoperatively between 2010 and 2019 at a high-volume tertiary care academic center. Participants were identified from a prospectively maintained database and had a median follow-up of 49 months. Data were analyzed from October 17 to November 24, 2020.The adaptive dynamic therapy group included 219 patients who remained on or switched to an alternative regimen as dictated by CA19-9 response and for whom the adjuvant regimen was selected based on CA19-9 and/or pathologic response. The nonadaptive dynamic therapy group included 103 patients who had their chemotherapeutic regimen selected independent of CA19-9 and/or tumoral response.Prognostic implications of dynamic perioperative therapy assessed through Kaplan-Meier analysis, Cox regression, and inverse probability weighted estimators.A total of 322 consecutive patients (mean [SD] age, 65.1 [9] years; 162 [50%] women) were identified. The adaptive dynamic therapy group, compared with the nonadaptive dynamic therapy group, had a more pronounced median (IQR) decrease in CA19-9 levels (-80% [-92% to -56%] vs -45% [-81% to -13%]; P .001), higher incidence of complete or near-complete tumoral response (25 [12%] vs 2 [2%]; P = .007), and lower median (IQR) number of lymph node metastasis (1 [0 to 4] vs 2 [0 to 4]; P = .046). Overall survival was significantly improved in the dynamic group compared with the nondynamic group (38.7 months [95% CI, 34.0 to 46.7 months] vs 26.5 months [95% CI, 23.5 to 32.9 months]; P = .03), and on adjusted analysis, dynamic therapy was independently associated with improved survival (hazard ratio, 0.73; 95% CI, 0.53 to 0.99; P = .04). On inverse probability weighted analysis of 320 matched patients, the average treatment effect of dynamic therapy was to increase overall survival by 11.1 months (95% CI, 1.5 to 20.7 months; P = .02).In this cohort study that sought to evaluate the role of adaptive dynamic therapy in localized pancreatic cancer, selecting a chemotherapeutic regimen based on response to preoperative therapy was associated with improved survival. These findings support an individualized and in vivo assessment of response to perioperative therapy in pancreatic cancer.

e16295 Background: Adjuvant chemotherapy improves survival following resection of pancreatic ductal adenocarcinoma (PDAC). A modified fluorouracil/irinotecan/oxaliplatin regimen (mFOLFIRINOX) has demonstrated improved disease free survival and overall survival, though gemcitabine-based monotherapy and gemcitabine plus capecitabine are alternatives in less fit patients. Though there are several proposed biomarkers to guide treatment decisions (GATA6, hENT1, and GemPred), no biomarker is used to guide treatment selection in clinical practice. Consequently, we sought to develop an artificial intelligence-derived signature of features from digital images of routine histopathology specimens that could identify patients susceptible to routine chemotherapeutic agents. Methods: 139 whole-slide digitized histological slides corresponding to 102 resected PDAC tumors from TCGA-PAAD were used in this study. This dataset corresponded to patients that had received either gemcitabine-backbone or 5 FU-backbone chemotherapy as their first-line adjuvant treatment. We extracted nuclei images from tissue regions using segmentation models and computed geometric features of these nuclei which we then correlated with Disease Specific Survival (DSS) in order to construct a signature associated with treatment benefit. This signature was compared against two board certified pathologists using the grade of the digital slides images to classify patients into above or below average DSS buckets. Results: Among quantitative geometric features, a set of area and ellipse features describing nuclei geometry correlated most with response to gemcitabine (R̃0.4). The cox proportional hazards model using these geometric nuclei features was found to be predictive of response to gemcitabine and achieved a C-index (95% CI) of 0.69 (0.58, 0.79). The pathologist-based baseline model for above and below average DSS had a median DSS of 443 and 461 days respectively. Using the average expected lifetime as the threshold, the model divides patients receiving gemcitabine into two histological subtypes with median DSS of 586 and 394 days respectively (p < 0.05). The model appeared specific to gemcitabine. Among patients receiving 5-FU (n = 10) there was no statistical significance in median DSS between the subtypes and a c-index of 0.63 (0.27, 1.0). Conclusions: An artificial intelligence approach utilizing only routine histopathology can identify features that correlate with treatment outcomes in PDAC with classification performance (c-index:0.69) superior to the validated AJCC treatment prediction tool (0.59).

RNF43 is an E3 ubiquitin ligase that is recurrently mutated in pancreatic ductal adenocarcinoma (PDAC) and precursor cystic neoplasms of the pancreas. The impact of RNF43 mutations on PDAC is poorly understood and autochthonous models have not been sufficiently characterized. In this study we describe a genetically engineered mouse model (GEMM) of PDAC with conditional expression of oncogenic Kras and deletion of the catalytic domain of Rnf43 (KRC) in exocrine cells. We demonstrate that Rnf43 loss results in an increased incidence of high-grade cystic lesions of the pancreas and PDAC. Importantly, KRC mice have a significantly decreased survival compared to mice containing only an oncogenic Kras mutation. By use of single cell RNA sequencing we demonstrated that KRC tumor progression is accompanied by a decrease in macrophages, as well as an increase in T and B lymphocytes with evidence of increased immune checkpoint molecule expression and affinity maturation, respectively. This was in stark contrast to the tumor immune microenvironment observed in the Kras/Tp53 driven PDAC GEMM. Furthermore, expression of the chemokine, CXCL5, was found to be specifically decreased in KRC cancer cells by means of epigenetic regulation and emerged as a putative candidate for mediating the unique KRC immune landscape. This GEMM establishes RNF43 as a bona fide tumor suppressor gene in PDAC and puts forth a rationale for an immunotherapy approach in this subset of PDAC cases.

Due to its poor prognosis and the late stage at which it is typically diagnosed, early detection of pancreatic cancer is a pressing clinical problem. Advances in genomic analysis of human pancreatic tissue and other biospecimens such as pancreatic cyst fluid, pancreatic juice and blood have opened the possibility of DNA-based molecular approaches for early detection of pancreatic cancer. In this Review, we discuss and focus on the pathological and molecular features of precancerous lesions of the pancreas, including pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm and mucinous cystic neoplasm, which are target lesions of early detection approaches. We also discuss the most prevalent genetic alterations in these precancerous lesions, including somatic mutations in the oncogenes KRAS and GNAS as well as tumour suppressor genes CDKN2A, TP53 and SMAD4. We highlight the latest discoveries related to genetic heterogeneity and multifocal neoplasia in precancerous lesions. In addition, we review specific approaches, challenges and clinically available assays for early detection of pancreatic cancer using DNA-based molecular techniques. Although detection and risk stratification of precancerous pancreatic neoplasms are difficult problems, progress in this field highlights the promise of molecular approaches for improving survival of patients with this disease.

Simple Summary Liver cancer is a dreadful tumor which has gradually increased in incidence all around the world. One major driver of liver cancer is the Wnt–β-catenin pathway which is active in a subset of these tumors. While this pathway is normally important in liver development, regeneration and homeostasis, it’s excessive activation due to mutations, is detrimental and leads to tumor cell growth, making it an important therapeutic target. There are also some unique characteristics of this pathway activation in liver cancer. It makes the tumor addicted to specific amino acids and in turn to mTOR signaling, which can be treated by certain existing therapies. In addition, activation of the Wnt–β-catenin in liver cancer appears to alter the immune cell landscape making it less likely to respond to the new immuno-oncology treatments. Thus, Wnt–β-catenin active tumors may need to be treated differently than non-Wnt–β-catenin active tumors. Abstract Hepatocellular cancer (HCC), the most common primary liver tumor, has been gradually growing in incidence globally. The whole-genome and whole-exome sequencing of HCC has led to an improved understanding of the molecular drivers of this tumor type. Activation of the Wnt signaling pathway, mostly due to stabilizing missense mutations in its downstream effector β-catenin (encoded by CTNNB1) or loss-of-function mutations in AXIN1 (the gene which encodes for Axin-1, an essential protein for β-catenin degradation), are seen in a major subset of HCC. Because of the important role of β-catenin in liver pathobiology, its role in HCC has been extensively investigated. In fact, CTNNB1 mutations have been shown to have a trunk role. β-Catenin has been shown to play an important role in regulating tumor cell proliferation and survival and in tumor angiogenesis, due to a host of target genes regulated by the β-catenin transactivation of its transcriptional factor TCF. Proof-of-concept preclinical studies have shown β-catenin to be a highly relevant therapeutic target in CTNNB1-mutated HCCs. More recently, studies have revealed a unique role of β-catenin activation in regulating both tumor metabolism as well as the tumor immune microenvironment. Both these roles have notable implications for the development of novel therapies for HCC. Thus, β-catenin has a pertinent role in driving HCC development and maintenance of this tumor-type, and could be a highly relevant therapeutic target in a subset of HCC cases.

ObjectiveRecent studies have found aristaless-related homeobox gene (ARX)/pancreatic and duodenal homeobox 1 (PDX1), alpha-thalassemia/mental retardation X-linked (ATRX)/death domain-associated protein (DAXX) and alternative lengthening of telomeres (ALT) to be promising prognostic biomarkers for non-functional pancreatic neuroendocrine tumours (NF-PanNETs). However, they have not been comprehensively evaluated, especially among small NF-PanNETs (≤2.0 cm). Moreover, their status in neuroendocrine tumours (NETs) from other sites remains unknown.DesignAn international cohort of 1322 NETs was evaluated by immunolabelling for ARX/PDX1 and ATRX/DAXX, and telomere-specific fluorescence in situ hybridisation for ALT. This cohort included 561 primary NF-PanNETs, 107 NF-PanNET metastases and 654 primary, non-pancreatic non-functional NETs and NET metastases. The results were correlated with numerous clinicopathological features including relapse-free survival (RFS).ResultsATRX/DAXX loss and ALT were associated with several adverse prognostic findings and distant metastasis/recurrence (pConclusionsATRX/DAXX and ALT should be considered in the prognostic evaluation of NF-PanNETs including ≤2.0 cm tumours, and are highly specific for pancreatic origin among NET metastases of unknown primary.

Histopathologically scoring the response of pancreatic ductal adenocarcinoma (PDAC) to neoadjuvant treatment can guide the selection of adjuvant therapy and improve prognostic stratification. However, several tumor response scoring (TRS) systems exist, and consensus is lacking as to which system represents best practice. An international consensus meeting on TRS took place in November 2019 in Amsterdam, The Netherlands. Here, we provide an overview of the outcomes and consensus statements that originated from this meeting. Consensus (≥80% agreement) was reached on a total of seven statements: (1) TRS is important because it provides information about the effect of neoadjuvant treatment that is not provided by other histopathology-based descriptors. (2) TRS for resected PDAC following neoadjuvant therapy should assess residual (viable) tumor burden instead of tumor regression. (3) The CAP scoring system is considered the most adequate scoring system to date because it is based on the presence and amount of residual cancer cells instead of tumor regression. (4) The defining criteria of the categories in the CAP scoring system should be improved by replacing subjective terms including “minimal” or “extensive” with objective criteria to evaluate the extent of viable tumor. (5) The improved, consensus-based system should be validated retrospectively and prospectively. (6) Prospective studies should determine the extent of tissue sampling that is required to ensure adequate assessment of the residual cancer burden, taking into account the heterogeneity of tumor response. (7) In future scientific publications, the extent of tissue sampling should be described in detail in the “Materials and methods” section.

Background SMAD4, a tumor suppressor gene, is inactivated or deleted in 60–90% of pancreatic adenocarcinomas (PDA). Loss of SMAD4 allows tumor progression by limiting cell cycle arrest and apoptosis and increasing metastases. SMAD4 deficient PDA cells are resistant to radiotherapy by upregulating autophagy, a cell survival mechanism that counteracts apoptotic mechanisms and allows intracellular recycling of macromolecules and organelles. Hydroxychloroquine (HCQ) is an orally available autophagy inhibitor with an established toxicity profile. We studied whether HCQ treatment in SMAD4 deficient PDA may prevent therapeutic resistance induced by autophagy upregulation. Methods We retrospectively analyzed the SMAD4 status of PDA patients enrolled in two prospective clinical trials evaluating administration of preoperative HCQ. The first dose escalation trial demonstrated the safety of preoperative gemcitabine with HCQ (NCT01128296). More recently, a randomized trial of gemcitabine/nab-paclitaxel +/- HCQ evaluated Evans Grade histopathologic response (NCT01978184). Immunohistochemistry of resected specimens for SMAD4 was previously performed. Patients not treated at the max HCQ dose (n = 5), not resected (n = 2) or with SMAD4 staining unavailable were excluded (n = 10). The effect of SMAD4 loss on response to HCQ and chemotherapy was studied for association with clinical outcome. Fisher’s exact test and log-rank test were used to assess response and survival. Results 52 patients receiving HCQ with neoadjuvant chemotherapy were studied. 25 of these patients had SMAD4 loss (48%). 76% of HCQ treated patients with SMAD4 loss obtained a histopathologic response ≥ 2A, compared to only 37% with SMAD4 intact (p = 0.006). In contrast with prevailing views, loss of SMAD4 was not associated with a detriment in median overall survival in HCQ treated patients (34.43 months in SMAD4 loss vs. 27.27 months in SMAD4 intact, p = 0.18). Conclusions The addition of HCQ to neoadjuvant chemotherapy in patients with PDA may improve treatment response in those with SMAD4 loss. Further study of the relationship between SMAD4, autophagy and treatment outcomes in PDA is warranted.

Background and aims HCC remains a major unmet clinical need. Although activating catenin beta-1 (CTNNB1) mutations are observed in prominent subsets of HCC cases, these by themselves are insufficient for hepatocarcinogenesis. Coexpression of mutant CTNNB1 with clinically relevant co-occurrence has yielded HCCs. Here, we identify cooperation between β-catenin and nuclear factor erythroid 2-related factor 2 (Nrf2) signaling in HCC. Approach and results Public HCC data sets were assessed for concomitant presence of CTNNB1 mutations and either mutations in nuclear factor erythroid-2-related factor-2 (NFE2L2) or Kelch like-ECH-associated protein 1 (KEAP1), or Nrf2 activation by gene signature. HCC development in mice and similarity to human HCC subsets was assessed following coexpression of T41A-CTNNB1 with either wild-type (WT)-, G31A-, or T80K-NFE2L2. Based on mammalian target of rapamycin complex 1 activation in CTNNB1-mutated HCCs, response of preclinical HCC to mammalian target of rapamycin (mTOR) inhibitor was investigated. Overall, 9% of HCC cases showed concomitant CTNNB1 mutations and Nrf2 activation, subsets of which were attributable to mutations in NFE2L2/KEAP1. Coexpression of mutated CTNNB1 with mutant NFE2L2, but not WT-NFE2L2, led to HCC development and mortality by 12-14 weeks. These HCCs were positive for β-catenin targets, like glutamine synthetase and cyclin-D1, and Nrf2 targets, like NAD(P)H quinone dehydrogenase 1 and peroxiredoxin 1. RNA-sequencing and pathway analysis showed high concordance of preclinical HCC to human HCC subset showing activation of unique (iron homeostasis and glioblastoma multiforme signaling) and expected (glutamine metabolism) pathways. NFE2L2-CTNNB1 HCC mice were treated with mTOR inhibitor everolimus (5-mg/kg diet ad libitum), which led to >50% decrease in tumor burden. Conclusions Coactivation of β-catenin and Nrf2 is evident in 9% of all human HCCs. Coexpression of mutant NFE2L2 and mutant CTNNB1 led to clinically relevant HCC development in mice, which responded to mTOR inhibitors. Thus, this model has both biological and therapeutic implications.

Intrahepatic cholangiocarcinoma (ICC), a disease of poor prognosis, has increased in incidence. It is challenging to treat due to intra- and inter-tumoral heterogeneity, which in part is attributed to diverse cellular origin. Indeed, co-expression of AKT and NICD in hepatocytes (HCs) yielded ICC, with similarity to proliferative, Notch-activated, and stem cell-like subclasses of clinical ICC. NICD regulated SOX9 and YAP1 during ICC development. Yap1 deletion or TEAD inhibition impaired HC-to-biliary epithelial cell (BEC) reprogramming and ICC proliferation; Sox9 loss repressed tumor growth; and Yap1-Sox9 combined loss abolished ICC development in AKT-NICD model. DNMT1 was discovered as a novel downstream effector of YAP1-TEAD complex that directed HC-to-BEC/ICC fate-switch. DNMT1 loss prevented Notch-dependent HC-to-ICC development, and DNMT1 re-expression restored ICC development following TEAD repression. Coexpression of DNMT1 with AKT was sufficient to induce hepatic tumor development including ICC. Thus, we have identified a novel NOTCH-YAP1/TEAD-DNMT1 axis essential for HC-driven ICC development.SIGNIFICANCEWe evaluated the clinical relevance of hepatocyte-driven ICC model and revealed critical but distinct roles of YAP1 and SOX9 in AKT-NICD-driven hepatocyte-derived ICC. We also identified NOTCH-YAP1/TEAD-DNMT1 axis as a critical driver for hepatocyte-to-ICC reprogramming, which might have biological and therapeutic implications in ICC subsets.

Background Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy, characterized by a desmoplastic stromal reaction and an immunosuppressive tumor microenvironment (TME)1. The metabolic stress within the PDAC TME promotes autophagy, a form of programmed cell survival associated with chemotherapeutic resistance and immune evasion.2, 3 Methods We conducted a randomized phase II study of preoperative gemcitabine and nab-paclitaxel with or without autophagy inhibition with oral hydroxychloroquine (HCQ) in patients with resectable PDAC. Autophagy inhibition increased Evans Grade histopathologic response and immune infiltrate.4Utilizing multiplex immunohistochemistry and dimer avoidance multiplex PCR-NGS5 in a subset of RNA extracted FFPE tumor specimens, we evaluated the adaptive immune response and immune correlates of response. Results Patients receiving HCQ had a greater CD4/CD8 immune infiltration (p = 0.033). Independent of treatment, a higher tumor immune infiltration score,6 was associated with improved overall survival (p = 0.035). Bulk tumor immunosequencing revealed a clonally expanded T cell receptor (TCR) Vβ (115±84 unique CDR3s (uCDR3s) of 3.3 × 104±2.4 total CDR3s) and B cell receptor (BCR) IgH (9.8 × 104±5.2 uCDR3s of 1.4 × 105±0.76 total CDR3s) repertoire compared to a paucity of TCR Vδ clones (2±1 uCDR3s of 43±60 total CDR3s). Patients with a higher than median TCR Vβ Diversity 50 Index (D50, proportion of uCDR3s that make up 50% of the total CDR3s) had significantly higher tumor CD4 (p = 0.003) and CD8 (p = 0.031) counts. Patients with a higher than median TRC Vβ D50 also had a reduced lymph node ratio (p = 0.039) and greater overall survival (p = 0.037, figure 1). Conversely, patients with a higher than median BCR IgH D50 had worse overall survival (p = 0.0241). Given the dichotomy of the TCR and BCR repertoire diversity and association with clinical outcome, we further analyzed the individual ratio of TRC Vβ:BCR IgH CDR3s and found that patients with a higher than median TRC Vβ:BCR IgH ratio had a greater Evan’s Grade histopathologic response (p = 0.069). Conclusions PDAC TIL repertoire with high TCR Vβ diversity is associated with decreased positive lymph node ratio and greater overall survival following neoadjuvant therapy. The divergent outcomes associated with increased intratumoral TCR and BCR diversity suggest a host response that may favor opposing T and B cell lymphocytic expansion. Regulation of this relationship may be explained by tumor MHC class I expression[3] or the presence of CD141+ cross presenting dendritic cells7, 8 and tertiary lymphoid structures,9 currently under investigation. Examination of repertoire modulating therapies is warranted. Trial Registration This trial (NCT01978184) was approved by the protocol review committee and IRB 13–074 at the University of Pittsburgh and performed in full accordance with the guidelines for good clinical practice and the Declaration of Helsinki. Written informed consent was obtained from all patients prior to any protocol treatment. References Ho WJ, Jaffee EM, Zheng L. The tumour microenvironment in pancreatic cancer - clinical challenges and opportunities. Nat Rev Clin Oncol 2020;17(9):527–540. Boone BA, Zeh HJ, 3rd, Bahary N. Autophagy inhibition in pancreatic adenocarcinoma. Clin Colorectal Cancer 2018;17(1):25–31. Yamamoto K, Venida A, Yano J, et al. Autophagy promotes immune evasion of pancreatic cancer by degrading MHC-I. Nature 2020;581(7806):100–105. Zeh HJ, Bahary N, Boone BA, et al. A Randomized phase ii preoperative study of autophagy inhibition with high-dose hydroxychloroquine and gemcitabine/nab-paclitaxel in pancreatic cancer patients. Clin Cancer Res 2020;26(13):3126–3134. Han J, Lotze MT. The adaptome as biomarker for assessing cancer immunity and immunotherapy. Methods Mol Biol2020; 2055:369–397. Hwang WT, Adams SF, Tahirovic E, Hagemann IS, Coukos G. Prognostic significance of tumor-infiltrating T cells in ovarian cancer: a meta-analysis. Gynecol Oncol. 2012;124(2):192–198. Spranger S, Dai D, Horton B, Gajewski TF. Tumor-Residing Batf3 Dendritic Cells Are Required for Effector T Cell Trafficking and Adoptive T Cell Therapy. Cancer Cell 2017;31(5):711–723 e714. Jang JE, Hajdu CH, Liot C, Miller G, Dustin ML, Bar-Sagi D. Crosstalk between regulatory T cells and tumor-associated dendritic cells negates anti-tumor immunity in pancreatic cancer. Cell Rep 2017;20(3):558–571. Bruno TC. New predictors for immunotherapy responses sharpen our view of the tumour microenvironment. Nature 2020;577(7791):474–476.

SummaryYAP1 regulates cell plasticity during liver injury, regeneration and cancer, but its role in liver development is unknown. YAP1 activity was detected in biliary cells and in cells at the hepato-biliary bifurcation in single-cell RNA-sequencing analysis of developing livers. Hepatoblast deletion ofYap1led to no impairment in Notch-driven SOX9+ ductal plate formation, but prevented the formation of the abutting second layer of SOX9+ ductal cells, blocking the formation of a patent intrahepatic biliary tree. Intriguingly, the mice survived for 8 months with severe cholestatic injury and without any hepatocyte-to-biliary transdifferentiation. Ductular reaction in the perihilar region suggested extrahepatic biliary proliferation likely seeking the missing intrahepatic biliary network. Long-term survival of these mice occurred through hepatocyte adaptation via reduced metabolic and synthetic function including altered bile acid metabolism and transport. Overall, we show YAP1 as a key regulator of bile duct development while highlighting a profound adaptive capability of hepatocytes.

Background The identification of genetic risk factors for chronic pancreatitis, such as PRSS1, CFTR and SPINK1, provides the opportunity to define key pathologic hallmarks and etiologic-specific changes. For example, pancreata from PRSS1 and CFTR patients exhibit progressive lipomatous atrophy without significant fibrosis. Considering the pathology of SPINK1-associated pancreatitis is ill-defined, we examined the pancreata of SPINK1 patients with chronic pancreatitis. Methods Histologic sections after total pancreatectomy with islet autotransplantation and associated clinicopathologic data were collected from 28 patients with SPINK1 germline alterations. Clinical findings, germline data, anatomic anomalies and pathologic findings were descriptively evaluated. Results Patients ranged in age from 5 to 48 years (median, 21.6 years) with abdominal pain between 2 and 25 years (median, 5.8 years). Most patients were SPINK1 heterozygous and 14 (50%) had co-occurring CFTR (n = 12) and CTRC (n = 2) mutations. Other pancreatitis risk factors included anatomic anomalies (n = 9) and tobacco use (n = 1). Overall, 24 (86%) patients had additional pancreatitis-associated germline alterations, SPINK1 homozygosity, anatomic anomalies or environmental factors. Examination of pancreata revealed a sequential pattern of exocrine parenchymal loss and replacement by prominent fibrosis, dependent on the duration of abdominal pain. No malignancies were identified, but low-grade pancreatic intraepithelial neoplasia was present for 2 cases. Conclusions Within this descriptive study, SPINK1-associated pancreatitis is characterized by parenchymal fibrosis and suggests divergent pathophysiologic mechanisms from PRSS1 and CFTR-associated pancreatitis. Moreover, SPINK1 patients frequently had additional etiologic factors that did not impact the development of pancreatic fibrosis and may implicate SPINK1 as a disease modifier gene.

BackgroundPreviously, we characterized subtypes of pancreatic ductal adenocarcinoma (PDAC) on computed-tomography (CT) scans, whereby conspicuous (high delta) PDAC tumors are more likely to have aggressive biology and poorer clinical outcomes compared to inconspicuous (low delta) tumors. Here, we hypothesized that these imaging-based subtypes would exhibit different growth-rates and distinctive metabolic effects in the period prior to PDAC diagnosis.Materials and methodsRetrospectively, we evaluated 55 patients who developed PDAC as a second primary cancer and underwent serial pre-diagnostic (T0) and diagnostic (T1) CT-scans. We scored the PDAC tumors into high and low delta on T1 and, serially, obtained the biaxial measurements of the pancreatic lesions (T0-T1). We used the Gompertz-function to model the growth-kinetics and estimate the tumor growth-rate constant (α) which was used for tumor binary classification, followed by cross-validation of the classifier accuracy. We used maximum-likelihood estimation to estimate initiation-time from a single cell (10-6 mm3) to a 10 mm3 tumor mass. Finally, we serially quantified the subcutaneous-abdominal-fat (SAF), visceral-abdominal-fat (VAF), and muscles volumes (cm3) on CT-scans, and recorded the change in blood glucose (BG) levels. T-test, likelihood-ratio, Cox proportional-hazards, and Kaplan-Meier were used for statistical analysis and p-value ResultsCompared to high delta tumors, low delta tumors had significantly slower average growth-rate constants (0.024 month−1 vs. 0.088 month−1, p−1. Leave-one-out-cross-validation showed 80% accuracy in predicting the delta-class (AUC=0.84). High delta tumors exhibited accelerated SAF, VAF, and muscle wasting (p ConclusionImaging-based subtypes of PDAC exhibit distinct growth, metabolic, and clinical profiles during the pre-diagnostic period. Our results suggest that heterogeneous disease biology may be an important consideration in early detection strategies for PDAC.

Goblet cell carcinoids (GCC) are an aggressive, albeit rare, subtype of appendiceal tumors that exhibit distinct histologic features and lack clear treatment guidelines. We aimed to ascertain the impact of adjuvant chemotherapy (AC) for GCC in a national cohort of patients.Patients who underwent a right hemicolectomy for stage I-III GCC of the appendix between 2006 and 2016 were selected from the National Cancer Database (NCDB). Stratification based on AC receipt was performed. Kaplan-Meier survival estimates and Cox proportional hazard regression were used to identify predictors of overall survival (OS).A total of 867 patients were identified, of whom 124 (14%) received AC. Patients in the AC group were significantly younger (54 vs. 57 years; p = 0.006) and were predominantly of male sex (60 vs. 48%; p = 0.012). On histopathology, patients in the AC group had a higher proportion of poorly/undifferentiated grade (27 vs. 5%; p 0.001), T4 disease (35 vs. 11%; p 0.001), and lymph node-positive disease (45 vs. 7%; p 0.001) than patients who did not receive AC. After excluding patients diagnosed in 2016 due to a lack of follow-up data (n = 162), a survival advantage for the AC group was detected only after stratification for lymph node-positive disease (p = 0.007). On Cox proportional hazard regression, AC demonstrated an independent association with improved OS (hazard ratio 0.24, 95% confidence interval 0.084-0.683; p = 0.007).The current analysis from the NCDB supports the role of AC for GCC of the appendix, chiefly for patients with lymph node metastatic disease.

BACKGROUND There are limited data on the efficacy of neoadjuvant therapy (NAT) for early-stage distal pancreas adenocarcinoma (PDAC). Previous studies focused on adenocarcinoma of the head of the pancreas or dealt with borderline and locally advanced tumors of the body and tail. METHODS This is a retrospective study of the National Cancer Database between 2006 and 2015. A propensity-matched analysis was performed to compare overall survival estimates between NAT and upfront resection (UR) groups. RESULTS A total of 5003 distal pancreatectomies for PDAC were identified, of whom 408 (9%) received NAT. After 1:1 matching, 353 NAT patients were compared with 353 UR patients. NAT was associated with lower 90-day mortality. There were no differences in the number of lymph nodes retrieved, or length of stay. With matching, the NAT group had higher median overall survival compared with UR (33.0 vs. 27.0 months; p = 0.009) and adjusted overall survival (hazard ratio = 0.63, 95% confidence interval = 0.51-0.77; p

Background & Aims The heterodimeric integrin receptor α4β7 regulates CD4 T cell recruitment to inflamed tissues, but its role in the pathogenesis of non-alcoholic steatohepatitis (NASH) is unknown. Herein, we examined the role of α4β7-mediated recruitment of CD4 T cells to the intestine and liver in NASH. Methods Male littermate F11r+/+ (control) and junctional adhesion molecule A knockout F11r−/− mice were fed a normal diet or a western diet (WD) for 8 weeks. Liver and intestinal tissues were analyzed by histology, quantitative reverse transcription PCR (qRT-PCR), 16s rRNA sequencing and flow cytometry. Colonic mucosa-associated microbiota were analyzed using 16s rRNA sequencing. Liver biopsies from patients with NASH were analyzed by confocal imaging and qRT-PCR. Results WD-fed knockout mice developed NASH and had increased hepatic and intestinal α4β7+ CD4 T cells relative to control mice who developed mild hepatic steatosis. The increase in α4β7+ CD4 T cells was associated with markedly higher expression of the α4β7 ligand mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the colonic mucosa and livers of WD-fed knockout mice. Elevated MAdCAM-1 expression correlated with increased mucosa-associated Proteobacteria in the WD-fed knockout mice. Antibiotics reduced MAdCAM-1 expression indicating that the diet-altered microbiota promoted colonic and hepatic MAdCAM-1 expression. α4β7 blockade in WD-fed knockout mice significantly decreased α4β7+ CD4 T cell recruitment to the intestine and liver, attenuated hepatic inflammation and fibrosis, and improved metabolic indices. MAdCAM-1 blockade also reduced hepatic inflammation and fibrosis in WD-fed knockout mice. Hepatic MAdCAM-1 expression was elevated in patients with NASH and correlated with higher expression of α4 and β7 integrins. Conclusions These findings establish α4β7/MAdCAM-1 as a critical axis regulating NASH development through colonic and hepatic CD4 T cell recruitment. Lay summary Non-alcoholic steatohepatitis (NASH) is an advanced and progressive form of non-alcoholic fatty liver disease (NAFLD), and despite its growing incidence no therapies currently exist to halt NAFLD progression. Herein, we show that blocking integrin receptor α4β7-mediated recruitment of CD4 T cells to the intestine and liver not only attenuates hepatic inflammation and fibrosis, but also improves metabolic derangements associated with NASH. These findings provide evidence for the potential therapeutic application of α4β7 antibody in the treatment of human NASH.

Background and AimsA subset of pancreatic ductal adenocarcinomas (PDACs) is highly resistant to systemic chemotherapy, but no markers are available in clinical settings to identify this subset. We hypothesized that chemotherapy-resistant PDACs express a glycan biomarker called sTRA. Methods. We tested this marker to identify treatment-resistant PDAC in multiple systems: sets of cell lines, organoids, and isogenic cell lines; primary tumors; and blood plasma from cohorts of human subjects. Results. Among a panel of 27 cell lines, high levels of cell-surface sTRA identified higher resistance to seven chemotherapeutics used against PDAC. Using primary tumors from two different cohorts, patients who were positive for a gene-expression classifier for sTRA received no statistically significant benefit from adjuvant chemotherapy, in contrast to those negative for the signature. In another cohort, using direct measurements of sTRA in tissue microarrays by quantitative immunofluorescence, patients who were high in sTRA again had no statistically significant benefit from adjuvant chemotherapy. Further, a blood-plasma test for the sTRA glycan identified the PDACs that showed rapid relapse following neoadjuvant chemotherapy. This blood test performed with 96% specificity and 56% sensitivity in a blinded cohort using samples collected before the start of treatment. Conclusion. These findings establish that tissue or plasma sTRA can identify PDACs that are resistant to neoadjuvant or adjuvant chemotherapy. This capability could help apply systemic treatments more precisely and facilitate biomarker-guided trials targeting resistant PDAC.

Brown bowel syndrome (BBS) is a rare condition associated with vitamin E deficiency and defined by prominent lipofuscin deposition in the muscularis propria. Eight unique cases of BBS were identified: 5 men and 3 women (mean age=58.6 y). Pertinent comorbidities included bariatric surgery=2, malnourishment=2, Crohn=2, cystic fibrosis=1, alcohol and cocaine abuse=1, and prior small bowel resections=1. Presenting symptoms included abdominal pain=3, bleeding=1, nausea and vomiting=1, and nonresponsiveness=1. Imaging studies were often abnormal: thickened bowel wall=3 (1 with a mass), small bowel obstruction=2, and edematous and dilated bowel wall=2. Most specimens were surgical resections (n=7, autopsy=1): extended right colectomy=2, small bowel only=5 (terminal ileum=3, jejunum=2). Two specimens were grossly described as mahogany, and 1 case contained a perforation. Histologic sections of all cases showed finely granular, brown cytoplasmic pigment in smooth muscle cells on hematoxylin and eosin. This pigment was most conspicuous in the muscularis propria (small bowel>colon), and it was not identified in the mucosa. The pigment was reactive with Fontana-Masson, carbol lipofuscin, Periodic acid-Schiff, and Periodic acid-Schiff with diastase, and electron microscopy was compatible with lipofuscin. The mean clinical follow-up was 208 weeks: 1 patient died of complications of encephalitis, the others were alive and well. BBS is important to recognize because it is linked with malnutrition, specifically vitamin E deficiency, and it can (rarely) clinically simulate malignancy. The diagnosis is based on the identification of the lipofuscin pigment in the cytoplasm of smooth muscle cells, which is most easily seen in the muscularis propria of the small bowel.

Mutations in RAS occur in 30–50% of metastatic colorectal carcinomas (mCRCs) and correlate with resistance to anti-EGFR therapy. Consequently, mCRC biomarker guidelines state RAS mutational testing should be performed when considering EGFR inhibitor treatment. However, a small subset of mCRCs are reported to harbor RAS amplification. In order to elucidate the clinicopathologic features and anti-EGFR treatment response associated with RAS amplification, we retrospectively reviewed a large cohort of mCRC patients that underwent targeted next-generation sequencing and copy number analysis for KRAS, NRAS, HRAS, BRAF and PIK3CA. Molecular testing was performed on 1,286 consecutive mCRC from 1,271 patients as part of routine clinical care, and results were correlated with clinicopathologic findings, mismatch repair (MMR) status and follow-up. RAS amplification was detected in 22 (2%) mCRCs and included: KRAS, NRAS and HRAS for 15, 5 and 2 cases, respectively (6 to 21 gene copies). Patients with a KRAS-amplified mCRC were more likely to report a history of inflammatory bowel disease (p < 0.001). In contrast, mutations in KRAS were associated with older patient age, right-sided colonic origin, low-grade differentiation, mucinous histology and MMR proficiency (p ≤ 0.017). Four patients with a KRAS-amplified mCRC and no concomitant RAS/BRAF/PIK3CA mutations received EGFR inhibitor-based therapy, and none demonstrated a clinicoradiographic response. The therapeutic impact of RAS amplification was further evaluated using a separate, multi-institutional cohort of 23 patients. Eight of 23 patients with KRAS-amplified mCRC received anti-EGFR therapy and all 8 patients exhibited disease progression on treatment. Although the number of KRAS-amplified mCRCs is limited, our data suggests the clinicopathologic features associated with mCRC harboring a KRAS amplification are distinct from those associated with a KRAS mutation. However, both alterations seem to confer EGFR inhibitor resistance and, therefore, RAS testing to include copy number analyses may be of consideration in the treatment of mCRC.

609 Background: Homologous recombination repair (HRR) is critical for limiting DNA damage arising from double strand breaks. Disrupting HRR has emerged as a therapeutic strategy in pancreatic cancer given the development of PARP inhibitors that can specifically target tumors with homologous recombination deficiency (HRD). While HRD is strongly associated with loss-of-function mutations in BRCA1/2, a broad range of pathogenic alterations have been identified in other HRR genes. Identification of pathogenic alterations that predict response to PARP inhibition remains a critical knowledge gap in the field. Methods: We retrospectively analyzed de-identified records from 895 patients with advanced pancreatic cancer that underwent next generation sequencing (NGS) with the Tempus|xT assay (DNA-seq of 648 genes at 500x coverage, matched normal, full transcriptome RNA-seq). HRD-positivity and genome-wide loss of heterozygosity (LOH) were compared across groups, which were defined based on alterations to BRCA1/2 or other HRR pathway genes. Results: We identified 293/895 (33%) pancreatic cancer patients to be HRD-positive. Among HRD positive patients, 23/895 (2.6%) tumors harbored two alterations in BRCA1/2 (BRCA++), 179/895 (20%) harbored a single alteration in BRCA1/2 (BRCA+), 25/895 (2.8%) harbored two alterations in at least one other non-BRCA HRR gene (other HRR++), 367/895 (41%) harbored a single alteration in one other HRR gene (other HRR+), and 143/895 (16%) had pathogenic alterations in neither BRCA1/2 nor other HRR genes. In terms of HRD status, 23/23 (100%) of BRCA++ cases, 179/337 (53%) of BRCA+ cases, 4/25 (16%) of other HRR++ cases, and 87/367 (24%) of other HRR+ cases were HRD-positive. We observed no cases that were HRD-positive without an alteration in either BRCA1/2 or other HRR gene. Within the other HRR+ group, we found that single alterations in CHEK1/2, FANCA/L, MRE11, PALB2, and RAD51B were all significantly associated with HRD-positivity whereas CDK12, for instance, was not (Table). Conclusions: Comprehensive genomic profiling demonstrates that approximately 1 in 4 patients without BRCA alterations may potentially benefit from PARP inhibition due to alterations in other HRR genes. Future studies may examine the role of PARP inhibition in this population of HRR+ pancreatic cancer patients.[Table: see text]

Purpose: We hypothesized that autophagy inhibition would increase response to chemotherapy in the preoperative setting for patients with pancreatic adenocarcinoma. We performed a randomized controlled trial to assess the autophagy inhibitor hydroxychloroquine in combination with gemcitabine and nab-paclitaxel. Patients and Methods: Participants with potentially resectable tumors were randomized to two cycles of nab-paclitaxel and gemcitabine (PG) alone or with hydroxychloroquine (PGH), followed by resection. The primary endpoint was histopathologic response in the resected specimen. Secondary clinical endpoints included serum CA 19-9 biomarker response and margin negative R0 resection. Exploratory endpoints included markers of autophagy, immune infiltrate, and serum cytokines. Results: Thirty-four patients in the PGH arm and 30 in the PG arm were evaluable for the primary endpoint. The PGH arm demonstrated statistically improved Evans grade histopathologic responses (P = 0.00016), compared with control. In patients with elevated CA 19-9, a return to normal was associated with improved overall and recurrence-free survival (P < 0.0001). There were no differences in serious adverse events between arms and chemotherapy dose number was equivalent. The PGH arm had greater evidence of autophagy inhibition in their resected specimens (increased SQSTM1, P = 0.027, as well as increased immune cell tumor infiltration, P = 0.033). Overall survival (P = 0.59) and relapse-free survival (P = 0.55) did not differ between the two arms. Conclusions: The addition of hydroxychloroquine to preoperative gemcitabine and nab-paclitaxel chemotherapy in patients with resectable pancreatic adenocarcinoma resulted in greater pathologic tumor response, improved serum biomarker response, and evidence of autophagy inhibition and immune activity.

OBJECTIVE. The goal of this study was to assess the correlation between CT-derived texture features of pancreatic ductal adenocarcinoma (PDAC) and histologic and biochemical markers of response to neoadjuvant treatment as well as disease-free survival in patients with potentially resectable PDAC. SUBJECTS AND METHODS. Thirty-nine patients completed this prospective study protocol between November 2013 and December 2016. All patients received neoadjuvant chemotherapy, underwent surgical resection, and had histologic grading of tumor response. Similar CT protocol was used for all patients. Pancreatic (late arterial) phase of pre- and posttreatment CT scans were evaluated. Histogram analysis and spatial-band-pass filtration were used to extract textural features. Correlation between textural parameters, histologic response, biochemical response, and genetic mutations was assessed using Mann-Whitney test, chi-square analysis, and multivariate logistic regression. Association with disease-free survival was assessed using Kaplan-Meier method and Cox model. RESULTS. Pretreatment mean positive pixel (MPP) at fine- and medium-level filtration, pretreatment kurtosis at medium-level filtration, changes in kurtosis, and pretreatment tumor SD were statistically different between patients with no or poor histologic response and favorable histologic response (p < 0.05). Changes in skewness and kurtosis at medium-level filtration significantly correlated with biochemical response (p < 0.01). On the basis of multivariate analysis, patients with higher MPP at pretreatment CT were more likely to have favorable histologic response (odds ratio, 1.06; 95% CI, 1.002-1.12). The Cox model for association between textural features and disease-free survival was statistically significant (p = 0.001). CONCLUSION. Textural features extracted from baseline pancreatic phase CT imaging of patients with potentially resectable PDAC and longitudinal changes in tumor heterogeneity can be used as biomarkers for predicting histologic response to neoadjuvant chemotherapy and disease-free survival.

In patients with pancreatic ductal adenocarcinoma (PDAC), increased expression of proinflammatory neurotrophic growth factors (eg, nerve growth factor [NGF]) correlates with a poorer prognosis, perineural invasion, and, with regard to NGF, pain severity. We hypothesized that NGF sequestration would reduce inflammation and disease in the KPC mouse model of PDAC.Following biweekly injections of NGF antibody or control immunoglobulin G, beginning at 4 or 8 weeks of age, inflammation and disease stage were assessed using histological, protein expression, and quantitative polymerase chain reaction analyses.In the 8-week anti-NGF group, indicators of neurogenic inflammation in the dorsal root ganglia (substance P and calcitonin gene-related peptide) and spinal cord (glial fibrillary acidic protein) were significantly reduced. In the 4-week anti-NGF group, TRPA1 mRNA in dorsal root ganglia and spinal phosphorylated ERK protein were elevated, but glial fibrillary acidic protein expression was unaffected. In the 8-week anti-NGF group, there was a 40% reduction in the proportion of mice with microscopic perineural invasion, and no macrometastases were observed.Anti-NGF treatment beginning at 4 weeks may increase inflammation and negatively impact disease. Treatment starting at 8 weeks (after disease onset), however, reduces neural inflammation, neural invasion, and metastasis. These data indicate that NGF impacts PDAC progression and metastasis in a temporally dependent manner.

Background. Adolescent obesity is a national epidemic that recently has been shown to increase risk for pancreatic adenocarcinoma (PC) and is associated with an earlier age of PC onset. We hypothesized that PC patients who are overweight or obese at age 18 would have an earlier age of PC onset. Methods. Retrospective review of 531 patients in our PC registry was completed. Self-reported weight at age 18 and maximum lifetime weight were used to calculate body mass index (BMI) at age 18 (BMI-18) and maximum lifetime BMI. Results. Complete BMI and baseline covariate data was available in 319 PC patients. Mean age (in years) of PC diagnosis for patients whose BMI-18 was overweight (64.0) or obese (59.9) was significantly different when compared to patients with a normal BMI-18 (66.7). No significant difference was observed in the mean age of PC diagnosis in those patients who maintained a normal BMI-18 when compared to those patients who subsequently became overweight or obese (67.0 versus 66.6; p=0.65). Conclusions. An elevated BMI at age 18 is associated with an earlier age of PC onset and should be factored into determining the optimal age of beginning screening for patients at high risk for PC.

BACKGROUND Approximately 10% of pancreatic adenocarcinoma (PC) cases are attributed to hereditary causes. Individuals with PC and a personal history of another cancer associated with hereditary breast and ovarian cancer (HBOC) or Lynch syndrome (LS) may be more likely to carry germline mutations. METHODS Participants with PC and a history of cancer were selected from a pancreatic disease registry. Of 1296 individuals with PC, 149 had a relevant history of cancer. If banked DNA was available, a multigene panel was performed for individuals who had not 1) previously had a mutation identified through clinical testing or 2) undergone clinical multigene panel testing with no mutations detected. RESULTS Twenty-two of 124 individuals with PC and another HBOC- or LS-related cancer who underwent genetic testing had a mutation identified in a PC susceptibility gene (18%). If prostate cancer is excluded, the mutation prevalence increased to 23% (21/93). Mutation carriers were more likely to have more than 1 previous cancer diagnosis (P = .001), to have had clinical genetic testing (P = .001), and to meet National Comprehensive Cancer Network (NCCN) genetic testing criteria (P < .001). Approximately 23% of mutation carriers did not meet NCCN HBOC or LS testing guidelines based on their personal cancer history and reported cancer history in first-degree relatives. CONCLUSION At least 18% of individuals with PC and a personal history of other HBOC- or LS-related cancers carry mutations in a PC susceptibility gene based on our data, suggesting that criteria for genetic testing in individuals with PC should include consideration of previous cancer history. Cancer 2018;124:1691-700. © 2018 American Cancer Society.

With increasing accessibility and advancements in abdominal imaging modalities, the incidence of pancreatic neuroendocrine neoplasms has increased steadily during the past few decades. By definition, neuroendocrine neoplasms of the pancreas show neuroendocrine differentiation, but they represent a broad and heterogeneous group of neoplasms with diverse clinical and pathological characteristics. The majority of pancreatic neuroendocrine neoplasms can be classified as well-differentiated pancreatic neuroendocrine tumours (PanNETs) or poorly differentiated pancreatic neuroendocrine carcinomas (PanNECs). While PanNETs and PanNECs are distinct entities with respect to clinical presentation, outcome and therapeutic approach, they may exhibit overlapping histopathological features. Moreover, the frequent modifications in nomenclature and prognostic grading systems over the years of not only pancreatic neuroendocrine neoplasms, but neuroendocrine neoplasms from other organ sites, has created confusion for both pathologists and clinicians as to the appropriate use of terminology and grading when evaluating these neoplasms. This review examines the current concepts and issues of nomenclature and grading of PanNETs and PanNECs. In addition, considering the morphological overlap between high-grade (G3) PanNETs and PanNECs, we discuss an integrative and practical diagnostic approach to aid in discriminating challenging cases.

PURPOSE/OBJECTIVE(S) Loss of the tumor suppressor gene SMAD4 is a critical genetic alteration in pancreatic carcinoma (PC). We hypothesized that SMAD4 status in PC is associated with outcomes in patients who received neoadjuvant (NARx) or adjuvant (ARx) radiotherapy. MATERIALS/METHODS PC patients who underwent surgical resection at two high-volume centers following NARx-or those treated with ARx-between 2008-2019 were identified. SMAD4 status was determined based on immunohistochemical staining and classified as preserved (SMAD4+) or lost (SMAD4-). Kaplan-Meier survival estimates and multivariate analysis were used to analyze correlations between SMAD4 status, radiation therapy, and clinical outcome measures. RESULTS A total of 290 patients (mean age at diagnosis 66 years, 51% female) were identified; 131 (45%) were SMAD4+ and 159 (55%) SMAD4-. Resectable disease was diagnosed in 95 (33%) and borderline-resectable disease in 166 (57%); 29 patients (10%) had locally-advanced disease. NARx was administered in 147 (51%) in combination with chemotherapy while 143 (49%) received ARx; 26 (18%) of which received ARx solely. NARx in SMAD4- PC was associated with a significantly increased incidence of near-complete/complete histopathologic response and reduced incidence of none/poor response compared to SMAD4- PC not treated with NARx (12% vs 2% and 44% vs 19% respectively, P = 0.001). On adjusted analysis, NARx was a significant predictor of histopathologic response in SMAD4- patients (HR: 3.5, 95% CI 1.6-7.6, P < 0.001) while no association was seen for SMAD4+ PC. Neither radiation therapy receipt nor SMAD4 status were associated with overall survival (OS). Yet, SMAD4- PC had a worsened disease-free survival (DFS) compared to SMAD4+ PC (19 vs 16 months, P = 0.03). This difference persisted even among patients who had received NARx (21 vs 16 months, P = 0.04) and those with histopathologic treatment response (24 vs 16 months, P = 0.031). No difference in DFS between SMAD4- and SMAD4+ PC was identified in the ARx group. Lastly, NARx, significantly improved local-recurrence free survival in SMAD4+ PC but not in SMAD4- PC (33 vs 21 months, P = 0.047). CONCLUSION `Outcomes following surgical resection for PC remain primarily driven by SMAD4 status irrespective of radiation therapy timing (NARx vs ARx). However, this analysis suggests that SMAD4 status may help identify a subset of patients who are most likely to benefit from NARx.

Esophageal epidermoid metaplasia is a rare condition that involves the proximal-to-middle third of the esophagus. It is sharply demarcated and defined histologically by epithelial hyperplasia, a prominent granular cell layer, and superficial hyperorthokeratosis. In addition, preliminary studies have suggested an association between esophageal epidermoid metaplasia and esophageal squamous neoplasia (squamous dysplasia and esophageal squamous cell carcinoma). To further characterize esophageal epidermoid metaplasia and better define its relationship to squamous neoplasia of the esophagus, we performed targeted next-generation sequencing on uninvolved esophageal squamous mucosa and matching esophageal epidermoid metaplasia specimens from 18 patients. Further, we evaluated both synchronous and metachronous high-grade squamous dysplasia/esophageal squamous cell carcinoma by next-generation sequencing from 5 of the 18 (28%) patients, and compared these findings to corresponding esophageal epidermoid metaplasia specimens. Targeted next-generation sequencing revealed 12 of 18 (67%) esophageal epidermoid metaplasia specimens' harbored alterations in genes often associated with esophageal squamous cell carcinoma. The most frequently mutated genes consisted of TP53 (n=10), PIK3CA (n=2), EGFR (n=2), MYCN (n=1), HRAS (n=1), and the TERT promoter (n=1). Sequencing of synchronous and metachronous high-grade squamous dysplasia/esophageal squamous cell carcinoma identified shared genetic alterations with corresponding esophageal epidermoid metaplasia specimens that suggests a clonal relationship between these entities. In addition, the presence of a TP53 mutation in esophageal epidermoid metaplasia specimens correlated with concurrent or progression to high-grade squamous dysplasia/esophageal squamous cell carcinoma. No genetic alterations were detected in uninvolved esophageal squamous mucosa. On the basis of these findings, we conclude esophageal epidermoid metaplasia is a precursor to in situ and invasive esophageal squamous neoplasia. Further, the detection of TP53 mutations in esophageal epidermoid metaplasia specimens may serve as an early detection biomarker for high-grade squamous dysplasia/esophageal squamous cell carcinoma.

A workshop was sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases to address the research gaps and opportunities in pancreatic endoscopic ultrasound (EUS). The event occurred on July 26, 2017 in 4 sessions: (1) benign pancreatic diseases, (2) high-risk pancreatic diseases, (3) diagnostic and therapeutics, and (4) new technologies. The current state of knowledge was reviewed, with identification of numerous gaps in knowledge and research needs. Common themes included the need for large multicenter consortia of various pancreatic diseases to facilitate meaningful research of these entities; to standardize EUS features of different pancreatic disorders, the technique of sampling pancreatic lesions, and the performance of various therapeutic EUS procedures; and to identify high-risk disease early at the cellular level before macroscopic disease develops. The need for specialized tools and accessories to enable the safe and effective performance of therapeutic EUS procedures also was discussed.

ObjectiveDNA-based testing of pancreatic cyst fluid (PCF) is a useful adjunct to the evaluation of pancreatic cysts (PCs). Mutations in KRAS/GNAS are highly specific for intraductal papillary mucinous neoplasms (IPMNs) and mucinous cystic neoplasms (MCNs), while TP53/PIK3CA/PTEN alterations are associated with advanced neoplasia. A prospective study was performed to evaluate preoperative PCF DNA testing.DesignOver 43-months, 626 PCF specimens from 595 patients were obtained by endoscopic ultrasound (EUS)-fine needle aspiration and assessed by targeted next-generation sequencing (NGS). Molecular results were correlated with EUS findings, ancillary studies and follow-up. A separate cohort of 159 PCF specimens was also evaluated for KRAS/GNAS mutations by Sanger sequencing.ResultsKRAS/GNAS mutations were identified in 308 (49%) PCs, while alterations in TP53/PIK3CA/PTEN were present in 35 (6%) cases. Based on 102 (17%) patients with surgical follow-up, KRAS/GNAS mutations were detected in 56 (100%) IPMNs and 3 (30%) MCNs, and associated with 89% sensitivity and 100% specificity for a mucinous PC. In comparison, KRAS/GNAS mutations by Sanger sequencing had a 65% sensitivity and 100% specificity. By NGS, the combination of KRAS/GNAS mutations and alterations in TP53/PIK3CA/PTEN had an 89% sensitivity and 100% specificity for advanced neoplasia. Ductal dilatation, a mural nodule and malignant cytopathology had lower sensitivities (42%, 32% and 32%, respectively) and specificities (74%, 94% and 98%, respectively).ConclusionsIn contrast to Sanger sequencing, preoperative NGS of PCF for KRAS/GNAS mutations is highly sensitive for IPMNs and specific for mucinous PCs. In addition, the combination of TP53/PIK3CA/PTEN alterations is a useful preoperative marker for advanced neoplasia.

Overexpression of HER2 protein and amplification of the ERBB2 gene has been observed in various adenocarcinomas, providing a therapeutic target that can be used to extend the survival of a select cohort of patients. Anti-HER2 therapy has been successfully applied to gastric and colorectal cancers, but its use and potential benefit in small intestinal carcinomas is not well characterized. We applied anti-HER2 therapy to an ERBB2-amplified advanced duodenal adenocarcinoma, adding trastuzumab to FOLFOX in the neoadjuvant setting. A 61-year-old woman with an advanced duodenal cancer harboring an ERBB2 amplification received preoperative trastuzumab and FOLFOX. Restaging revealed significant tumor downstaging with no metastasis. After multidisciplinary assessment, she underwent pancreaticoduodenectomy. Final pathologic analysis revealed no residual invasive adenocarcinoma, consistent with a complete neoadjuvant treatment response. This case report emphasizes the need for further molecular characterization of small bowel cancers; genetic alterations may provide therapeutic targets to improve the prognosis of these rare and aggressive malignancies.

Universal screening for Lynch syndrome has been advocated for colorectal carcinoma but its utility in small bowel adenocarcinoma has not been reported. We analyzed a consecutive series of 71 small bowel adenocarcinomas identified over an 8-year period for DNA mismatch repair (MMR) protein expression to (1) compare the clinicopathologic features of small bowel adenocarcinoma stratified into MMR-deficient (MMRD) and MMR-proficient (MMRP) groups and (2) examine the patterns of MMR protein expression in small bowel adenocarcinoma compared with colorectal carcinoma. Six of 71 (8.5%) small bowel adenocarcinomas and 149 of 1291 (11.5%) colorectal carcinomas demonstrated MMRD. The 6 MMRD small bowel adenocarcinomas had the following expression pattern: 3 with concurrent loss of MSH2 and MSH6, 1 with isolated loss of MSH6, and 2 with concurrent loss of MLH1 and PMS2 in patients with a family history suggestive of genetic cancer susceptibility. Histopathology suggestive of MMR protein deficiency as proposed by the revised Bethesda guidelines was commonly seen in both MMRP (63%) and MMRD (67%) small bowel adenocarcinomas (P>0.05). MMRD small bowel adenocarcinoma more frequently demonstrated abnormalities of MSH2 and/or MSH6 (4/6, 67%) compared with MMRD colorectal carcinoma (23/149, 15%) (P=0.01). None of the MMRD small bowel adenocarcinomas harbored the BRAF V600E mutation, whereas 60% of MMRD colorectal carcinomas were positive for BRAF V600E with concurrent loss of MLH1 and PMS2 expression. Small bowel adenocarcinoma more frequently harbored Lynch syndrome-associated MMRD compared with colorectal carcinoma, providing support for screening of small bowel adenocarcinoma to identify patients at risk for Lynch syndrome. In contrast to colorectal carcinoma, sporadic MLH1 deficiency is not seen in small bowel adenocarcinoma. Clinicopathologic and histologic features do not distinguish between MMRP and MMRD small bowel adenocarcinoma indicating that universal screening in small bowel adenocarcinoma is necessary to detect patients at risk for Lynch syndrome.

Background: Given the tolerability of nPG in first-line therapy, we desired to evaluate the response and toxicity profiles of second-line gemcitabine with nab-paclitaxel (nPG) following FOLFIRINOX. Methods: We retrospectively identified 30 patients who received first-line FOLFIRINOX for unresectable or metastatic pancreatic adenocarcinoma followed by second-line nPG. Response was evaluated by RECIST criteria and carbohydrate antigen 19-9 (CA19-9) change. Results: Median age was 63 years with 77% percent having metastatic disease. Nineteen patients (63%) achieved PR based on CA19-9. Median overall survival (OS) with nPG was 12.4 months (mo) and median progression-free survival (PFS) was 3.7 mo. Median PFS and OS for patients with at least stable CA19-9 were 4.7 and 13.9 mo since initiation of nPG. Patients with an increased CA19-9 level during nPG had a shorter median PFS (1.4 mo) and OS (5.3 mo). A significant PFS difference was demonstrated in patients with at least stable disease as the best RECIST response versus in those with progressive disease (5.4 vs. 1.9 mo, P Conclusions: This study demonstrates a clinical benefit of second-line nPG. The study also suggests a possible use of CA19-9 to predict response to therapy.

McCune-Albright Syndrome (MAS) is a rare sporadic syndrome caused by post-zygotic mutations in the GNAS oncogene, leading to constitutional mosaicism for these alterations. Somatic activating GNAS mutations also commonly occur in several gastrointestinal and pancreatic neoplasms, but the spectrum of abnormalities in these organs in patients with MAS has yet to be systematically described. We report comprehensive characterization of the upper gastrointestinal tract in seven patients with MAS and identify several different types of polyps, including gastric heterotopia/metaplasia (7/7), gastric hyperplastic polyps (5/7), fundic gland polyps (2/7), and a hamartomatous polyp (1/7). In addition, one patient had an unusual adenomatous lesion at the gastroesophageal junction with high-grade dysplasia. In the pancreas, all patients had endoscopic ultrasound findings suggestive of intraductal papillary mucinous neoplasm (IPMN), but only two patients met the criteria for surgical intervention. Both of these patients had IPMNs at resection, one with low-grade dysplasia and one with high-grade dysplasia. GNAS mutations were identified in the majority of lesions analyzed, including both IPMNs and the adenomatous lesion from the gastroesophageal junction. These studies suggest that there is a broad spectrum of abnormalities in the gastrointestinal tract and pancreas in patients with MAS and that patients with MAS should be evaluated for gastrointestinal pathology, some of which may warrant clinical intervention due to advanced dysplasia.

The impact of genomic profiling on the outcomes of patients with advanced gastrointestinal (GI) malignancies remains unknown. The primary objectives of the study were to investigate the clinical benefit of genomic‐guided therapy, defined as complete response (CR), partial response (PR), or stable disease (SD) at 3 months, and its impact on progression‐free survival (PFS) in patients with advanced GI malignancies. Clinical and genomic data of all consecutive GI tumor samples from April, 2013 to April, 2016 sequenced by FoundationOne were obtained and analyzed. A total of 101 samples from 97 patients were analyzed. Ninety‐eight samples from 95 patients could be amplified making this approach feasible in 97% of the samples. After removing duplicates, 95 samples from 95 patients were included in the further analysis. Median time from specimen collection to reporting was 11 days. Genomic alteration‐guided treatment recommendations were considered new and clinically relevant in 38% (36/95) of the patients. Rapid decline in functional status was noted in 25% (9/36) of these patients who could therefore not receive genomic‐guided therapy. Genomic‐guided therapy was utilized in 13 patients (13.7%) and 7 patients (7.4%) experienced clinical benefit (6 PR and 1 SD). Among these seven patients, median PFS was 10 months with some ongoing durable responses. Genomic profiling‐guided therapy can lead to clinical benefit in a subset of patients with advanced GI malignancies. Attempting genomic profiling earlier in the course of treatment prior to functional decline may allow more patients to benefit from these therapies.

Chronic pancreatitis is a debilitating condition often associated with severe abdominal pain and exocrine and endocrine dysfunction. The underlying cause is multifactorial and involves complex interaction of environmental, genetic, and/or other risk factors. The pathology is dependent on the underlying pathogenesis of the disease. This review describes the clinical, gross, and microscopic findings of the main subtypes of chronic pancreatitis: alcoholic chronic pancreatitis, obstructive chronic pancreatitis, paraduodenal ("groove") pancreatitis, pancreatic divisum, autoimmune pancreatitis, and genetic factors associated with chronic pancreatitis. As pancreatic ductal adenocarcinoma may be confused with chronic pancreatitis, the main distinguishing features between these 2 diseases are discussed.

Background &amp, Aims: ARID1A is postulated to be a tumor suppressor gene owing to loss-of-function mutations in human pancreatic ductal adenocarcinomas (PDAC). However, its role in pancreatic pathogenesis is not clear despite recent studies using genetically engineered mouse (GEM) models. We aimed at further understanding of its direct functional role in PDAC, using a combination of GEM model and PDAC cell lines. Methods: Pancreas-specific mutant Arid1a-driven GEM model (Ptf1a-Cre, KrasG12D, Arid1af/f or &ldquo, KAC&rdquo, ) was generated by crossing Ptf1a-Cre, KrasG12D (&ldquo, KC&rdquo, ) mice with Arid1af/f mice and characterized histologically with timed necropsies. Arid1a was also deleted using CRISPR-Cas9 system in established human and murine PDAC cell lines to study the immediate effects of Arid1a loss in isogenic models. Cell lines with or without Arid1a expression were developed from respective autochthonous PDAC GEM models, compared functionally using various culture assays, and subjected to RNA-sequencing for comparative gene expression analysis. DNA damage repair was analyzed in cultured cells using immunofluorescence and COMET assay. Results: Retention of Arid1a is critical for early progression of mutant Kras-driven pre-malignant lesions into PDAC, as evident by lower Ki-67 and higher apoptosis staining in &ldquo, as compared to &ldquo, mice. Enforced deletion of Arid1a in established PDAC cell lines caused suppression of cellular growth and migration, accompanied by compromised DNA damage repair. Despite early development of relatively indolent cystic precursor lesions called intraductal papillary mucinous neoplasms (IPMNs), a subset of &ldquo, mice developed aggressive PDAC in later ages. PDAC cells obtained from older autochthonous &ldquo, mice revealed various compensatory (&ldquo, escaper&rdquo, ) mechanisms to overcome the growth suppressive effects of Arid1a loss. Conclusions: Arid1a is an essential survival gene whose loss impairs cellular growth, and thus, its expression is critical during early stages of pancreatic tumorigenesis in mouse models. In tumors that arise in the setting of ARID1A loss, a multitude of &ldquo, mechanisms drive progression.

BACKGROUND & AIMS: Intraductal oncocytic papillary neoplasms (IOPNs) of the pancreas and bile duct contain epithelial cells with numerous, large mitochondria and are cystic precursors to pancreatic ductal adenocarcinoma (PDAC) and cholangiocarcinoma (CCA), respectively. However, IOPNs do not have the genomic alterations found in other pancreatobiliary neoplasms. In fact, no recurrent genomic alterations have been described in IOPNs. PDACs without activating mutations in KRAS contain gene rearrangements, so we investigated whether IOPNs have recurrent fusions in genes. METHODS: We analyzed 20 resected pancreatic IOPNs and 3 resected biliary IOPNs using a broad RNA-based targeted sequencing panel to detect cancer-related fusion genes. Four invasive PDACs and 2 intrahepatic cholangiocarcinomas from the same patients as the IOPNs, were also available for analysis. Samples of pancreatic cyst fluid (n=5, collected before surgery) and bile duct brushings (n=2) were analyzed for translocations. For comparison, we analyzed pancreatobiliary lesions from 126 patients without IOPN (controls). RESULTS: All IOPNs evaluated were found to have recurring fusions of ATP1B1-PRKACB (n = 13), DNAJB1–PRKACA (n = 6), or ATP1B1–PRKACA (n = 4). These fusions were also found in corresponding invasive PDACs and intrahepatic cholangiocarcinomas, as well as in matched pancreatic cyst fluid and bile duct brushings. These gene rearrangements were absent from all 126 control pancreatobiliary lesions. CONCLUSIONS: We identified fusions in PRKACA and PRKACB genes in pancreatic and biliary IOPNs, as well as in PDACs and pancreatic cyst fluid and bile duct cells from the same patients. We did not identify these gene fusions in 126 control pancreatobiliary lesions. These fusions might be used to identify patients at risk for IOPNs and their associated invasive carcinomas.

BACKGROUND: Neoadjuvant therapy (NAT) is increasingly utilized for pancreatic cancer, however the added benefit of adjuvant therapy (AT) in this setting is unknown. We hypothesized that the magnitude of CA19-9 response to NAT can guide the need for further AT in resected pancreatic cancer. METHODS: CA19-9 secretors who received NAT for pancreatic cancer during 2008–2016 at a single institution were analyzed and CA19-9 response (difference between pre and post NAT values) was measured. Kaplan-Meier estimators and Cox proportional hazard ratio models were used to determine the optimal CA19-9 response at which AT ceases to confer any additional survival benefit after NAT. RESULTS: A total of 241 patient (mean age 65.4yrs, 50% female) with complete CA19-9 data who underwent NAT followed by resection were analyzed. In a cohort of patients (n=78) in whom CA19-9 normalized with a decrease >50% after NAT (optimal responders), AT was not associated with additional survival benefit (40.6 versus 39.0 months, p=0.815). Conversely, in the cohort of patients (n=163) in whom NAT was not associated with normalization and decrease ≤50% in CA19-9 (sub-optimal responders), receipt of AT was associated with a survival benefit (34.5 versus 19.1 months, p50% during NAT to predict no additional survival benefit from adjuvant therapy. CONCLUSIONS: The magnitude of CA19-9 response to NAT may predict the need for further adjuvant therapy in resected pancreatic cancer. Prospective studies are needed to elucidate the optimal interplay of NAT and AT in pancreatic cancer.

Pancreatic cysts are common and often pose a management dilemma, because some cysts are precancerous, whereas others have little risk of developing into invasive cancers. We used supervised machine learning techniques to develop a comprehensive test, CompCyst, to guide the management of patients with pancreatic cysts. The test is based on selected clinical features, imaging characteristics, and cyst fluid genetic and biochemical markers. Using data from 436 patients with pancreatic cysts, we trained CompCyst to classify patients as those who required surgery, those who should be routinely monitored, and those who did not require further surveillance. We then tested CompCyst in an independent cohort of 426 patients, with histopathology used as the gold standard. We found that clinical management informed by the CompCyst test was more accurate than the management dictated by conventional clinical and imaging criteria alone. Application of the CompCyst test would have spared surgery in more than half of the patients who underwent unnecessary resection of their cysts. CompCyst therefore has the potential to reduce the patient morbidity and economic costs associated with current standard-of-care pancreatic cyst management practices.