CLDN6-specific CAR-T cells plus amplifying RNA vaccine in relapsed or refractory solid tumors: the phase 1 BNT211-01 trial

The oncofetal antigen Claudin 6 (CLDN6) is highly and specifically expressed in many solid tumors, and could be a promising treatment target. We report dose escalation results from the ongoing phase 1/2 BNT211-01 trial evaluating the safety and feasibility of chimeric antigen receptor (CAR) T cells targeting the CLDN6 with or without a CAR-T cell-amplifying RNA vaccine (CARVac) at two dose levels (DLs) in relapsed/refractory CLDN6-positive solid tumors. The primary endpoints were safety and tolerability, maximum tolerated dose and recommended phase 2 dose (RP2D). Secondary endpoints included objective response rate (ORR) and disease control rate. We observed manageable toxicity, with 10 out of 22 patients (46%) experiencing cytokine release syndrome including one grade 3 event and 1 out of 22 (5%) with grade 1 immune effector cell-associated neurotoxicity syndrome. Dose-limiting toxicities occurred in two patients at the higher DL, resolving without sequelae. CAR-T cell engraftment was robust, and the addition of CARVac was well tolerated. The unconfirmed ORR in 21 evaluable patients was 33% (7 of 21), including one complete response. The disease control rate was 67% (14 of 21), with stable disease in seven patients. Patients with germ cell tumors treated at the higher DL exhibited the highest response rate (ORR 57% (4 of 7)). The maximum tolerated dose and RP2D were not established as the trial has been amended to utilize an automated manufacturing process. A repeat of the dose escalation is ongoing and will identify a RP2D for pivotal trials. ClinicalTrials.gov Identifier: NCT04503278 .

GATA4 and GATA6 loss-of-expression is associated with extinction of the classical programme and poor outcome in pancreatic ductal adenocarcinoma

OBJECTIVE

GATA6 is a key regulator of the classical phenotype in pancreatic ductal adenocarcinoma (PDAC). Low GATA6 expression associates with poor patient outcome. GATA4 is the second most expressed GATA factor in the pancreas. We assessed whether, and how, GATA4 contributes to PDAC phenotype and analysed the association of expression with outcome and response to chemotherapy.

DESIGN

We analysed PDAC transcriptomic data, stratifying cases according to GATA4 and GATA6 expression and identified differentially expressed genes and pathways. The genome-wide distribution of GATA4 was assessed, as well as the effects of GATA4 knockdown. A multicentre tissue microarray study to assess GATA4 and GATA6 expression in samples (n=745) from patients with resectable was performed. GATA4 and GATA6 levels were dichotomised into high/low categorical variables; association with outcome was assessed using univariable and multivariable Cox regression models.

RESULTS

GATA4 messenger RNA is enriched in classical, compared with basal-like tumours. We classified samples in 4 groups as high/low for GATA4 and GATA6. Reduced expression of GATA4 had a minor transcriptional impact but low expression of GATA4 enhanced the effects of GATA6 low expression. GATA4 and GATA6 display a partially overlapping genome-wide distribution, mainly at promoters. Reduced expression of both proteins in tumours was associated with the worst patient survival. GATA4 and GATA6 expression significantly decreased in metastases and negatively correlated with basal markers.

CONCLUSIONS

GATA4 and GATA6 cooperate to maintain the classical phenotype. Our findings provide compelling rationale to assess their expression as biomarkers of poor prognosis and therapeutic response.

Molecular heterogeneity and commonalities in pancreatic cancer precursors with gastric and intestinal phenotype

OBJECTIVE

Due to the limited number of modifiable risk factors, secondary prevention strategies based on early diagnosis represent the preferred route to improve the prognosis of pancreatic ductal adenocarcinoma (PDAC). Here, we provide a comparative morphogenetic analysis of PDAC precursors aiming at dissecting the process of carcinogenesis and tackling the heterogeneity of preinvasive lesions.

DESIGN

Targeted and whole-genome low-coverage sequencing, genome-wide methylation and transcriptome analyses were applied on a final collective of 122 morphologically well-characterised low-grade and high-grade PDAC precursors, including intestinal and gastric intraductal papillary mucinous neoplasms (IPMN) and pancreatic intraepithelial neoplasias (PanIN).

RESULTS

Epigenetic regulation of mucin genes determines the phenotype of PDAC precursors. PanIN and gastric IPMN display a ductal molecular profile and numerous similarly regulated pathways, including the Notch pathway, but can be distinguished by recurrent deletions and differential methylation and, in part, by the expression of mucin-like 3. Intestinal IPMN are clearly distinct lesions at the molecular level with a more instable genotype and are possibly related to a different ductal cell compartment.

CONCLUSIONS

PDAC precursors with gastric and intestinal phenotype are heterogeneous in terms of morphology, genetic and epigenetic profile. This heterogeneity is related to a different cell identity and, possibly, to a different aetiology.

Pathological Reporting of Radical Prostatectomy Specimens Following ICCR Recommendation: Impact of Electronic Reporting Tool Implementation on Quality and Interdisciplinary Communication in a Large University Hospital

Prostate cancer represents one of the most common malignant tumors in male patients in Germany. The pathological reporting of radical prostatectomy specimens following a structured process constitutes an excellent prototype for the introduction of software-based standardized structured reporting in pathology. This can lead to reports of higher quality and could create a fundamental improvement for future AI applications. A software-based reporting template was used to generate standardized structured pathological reports of radical prostatectomy specimens of patients treated at the University Hospital Klinikum rechts der Isar of Technische Universität München, Germany. Narrative reports (NR) and standardized structured reports (SSR) were analyzed with regard to completeness, and clinicians' satisfaction with each report type was evaluated. SSR show considerably higher completeness than NR. A total of 10 categories out of 32 were significantly more complete in SSR than in NR (p < 0.05). Clinicians awarded overall high scores in NR and SSR reports. One rater acknowledged a significantly higher level of clarity and time saving when comparing SSR to NR. Our findings highlight that the standardized structured reporting of radical prostatectomy specimens, qualifying as level 5 reports, significantly increases objectively measured content quality and the level of completeness. The implementation of nationwide SSR in Germany, particularly in oncologic pathology, can serve pathologists, clinicians, and patients.

A modified burn comb model with a new dorsal frame that allows for local treatment in partial-thickness burns in rats

Burn wound progression (BWP) leads to vertical and horizontal injury extension. The "burn comb model" is commonly used, in which a full-thickness burn with intercalated unburned interspaces is induced. We aimed to establish an injury progressing to the intermediate dermis, allowing repeated wound evaluation. Furthermore, we present a new dorsal frame that enables topical drug application. 8 burn field and 6 interspaces were induced on each of 17 rats' dorsa with a 10-second burn comb application. A developed 8-panel aluminum frame was sutured onto 12 animals and combined with an Elizabethan collar. Over 14 days, macroscopic & histologic wound assessment and Laser-Speckle-Contrast-Imaging (LSCI) were performed besides evaluation of frame durability. The 10-second group was compared to 9 animals injured with a full-thickness 60-second model. Frame durability was sufficient up to day 4 with 8 of 12 frames (67%) still mounted. The 60-second burn led to an increased extent of interspace necrosis (p=0.002). The extent of necrosis increased between days 1 and 2 (p=0.001), following the 10-second burn (24%±SEM 8% to 40%±SEM 6%) and the 60-second burn (57%±SEM 6% to 76%±SEM 4%). Interspace LSCI perfusion was higher than burn field perfusion. It earlier reached baseline levels in the 10-second group (on day 1: 142%±SEM 9% vs. 60%±SEM 5%; p<0.001). Within day 1, the 10-second burn showed histological progression to the intermediate dermis, both in interspaces and burn fields. This burn comb model with its newly developed fixed dorsal frame allows investigation of topical agents to treat BWP in partial-thickness burns.

Integrative analysis reveals early and distinct genetic and epigenetic changes in intraductal papillary and tubulopapillary cholangiocarcinogenesis

OBJECTIVE

A detailed understanding of the molecular alterations in different forms of cholangiocarcinogenesis is crucial for a better understanding of cholangiocarcinoma (CCA) and may pave the way to early diagnosis and better treatment options.

DESIGN

We analysed a clinicopathologically well-characterised patient cohort (n=54) with high-grade intraductal papillary (IPNB) or tubulopapillary (ITPN) neoplastic precursor lesions of the biliary tract and correlated the results with an independent non-IPNB/ITPN associated CCA cohort (n=294). The triplet sample set of non-neoplastic biliary epithelium, precursor and invasive CCA was analysed by next generation sequencing, DNA copy number and genome-wide methylation profiling.

RESULTS

Patients with invasive CCA arising from IPNB/ITPN had better prognosis than patients with CCA not associated with IPNB/ITPN. ITPN was localised mostly intrahepatic, whereas IPNB was mostly of extrahepatic origin. IPNB/ITPN were equally associated with small-duct and large-duct type intrahepatic CCA. IPNB exhibited mutational profiles of extrahepatic CCA, while ITPN had significantly fewer mutations. Most mutations were shared between precursor lesions and corresponding invasive CCA but ROBO2 mutations occurred exclusively in invasive CCA and CTNNB1 mutations were mainly present in precursor lesions. In addition, IPNB and ITPN differed in their DNA methylation profiles and analyses of latent methylation components suggested that IPNB and ITPN may have different cells-of-origin.

CONCLUSION

Integrative analysis revealed that IPNB and ITPN harbour distinct early genetic alterations, IPNB are enriched in mutations typical for extrahepatic CCA, whereas ITPN exhibited few genetic alterations and showed distinct epigenetic profiles. In conclusion, IPNB/ITPN may represent a distinctive, intermediate form of intrahepatic and extrahepatic cholangiocarcinogenesis.

Native glycan fragments detected by MALDI mass spectrometry imaging are independent prognostic factors in pancreatic ductal adenocarcinoma

Background

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest malignancies to date. The impressively developed stroma that surrounds and modulates the behavior of cancer cells is one of the main factors regulating the PDAC growth, metastasis and therapy resistance. Here, we postulate that stromal and cancer cell compartments differentiate in protein/lipid glycosylation patterns and analyze differences in glycan fragments in those compartments with clinicopathologic correlates.

Results

We analyzed native glycan fragments in 109 human FFPE PDAC samples using high mass resolution matrix-assisted laser desorption/ionization Fourier-transform ion cyclotron resonance mass spectrometric imaging (MALDI-FT-ICR-MSI). Our method allows detection of native glycan fragments without previous digestion with PNGase or any other biochemical reaction. With this method, 8 and 18 native glycans were identified as uniquely expressed in only stromal or only cancer cell compartment, respectively. Kaplan–Meier survival model identified glycan fragments that are expressed in cancer cell or stromal compartment and significantly associated with patient outcome. Among cancer cell region-specific glycans, 10 predicted better and 6 worse patient survival. In the stroma, 1 glycan predicted good and 4 poor patient survival. Using factor analysis as a dimension reduction method, we were able to group the identified glycans in 2 factors. Multivariate analysis revealed that these factors can be used as independent survival prognostic elements with regard to the established Union for International Cancer Control (UICC) classification both in tumor and stroma regions.

Conclusion

Our method allows in situ detection of naturally occurring glycans in FFPE samples of human PDAC tissue and highlights the differences among glycans found in stromal and cancer cell compartment offering a basis for further exploration on the role of specific glycans in cancer–stroma communication.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13550-021-00862-y.

The Impact of Histological Annotations for Accurate Tissue Classification Using Mass Spectrometry Imaging

Knowing the precise location of analytes in the tissue has the potential to provide information about the organs’ function and predict its behavior. It is especially powerful when used in diagnosis and prognosis prediction of pathologies, such as cancer. Spatial proteomics, in particular mass spectrometry imaging, together with machine learning approaches, has been proven to be a very helpful tool in answering some histopathology conundrums. To gain accurate information about the tissue, there is a need to build robust classification models. We have investigated the impact of histological annotation on the classification accuracy of different tumor tissues. Intrinsic tissue heterogeneity directly impacts the efficacy of the annotations, having a more pronounced effect on more heterogeneous tissues, as pancreatic ductal adenocarcinoma, where the impact is over 20% in accuracy. On the other hand, in more homogeneous samples, such as kidney tumors, histological annotations have a slenderer impact on the classification accuracy.

An analysis of 130 neuroendocrine tumors G3 regarding prevalence, origin, metastasis, and diagnostic features

Limited data exist on high-grade neuroendocrine tumors (NETs G3) which represent a new category among neuroendocrine neoplasms (NEN). We analyzed NETs G3 in a consultation series regarding prevalence, origin, metastasis, and diagnostic problems. Based on the WHO classification of digestive system tumors, 130 NETs G3 (9%) were identified in 1513 NENs. NET G3 samples were more often obtained from metastatic sites (69%) than NET G1/G2 samples (24%). NET G3 metastases presented most frequently in the liver (74%) and originated from the pancreas (38/90, 42%), followed by the lung (9%), ileum (7%), stomach (3%), rectum (1%), and rare sites (2%) such as the prostate and breast. The primaries remained unknown in 15%. NETs G3 had a median Ki67 of 30% that distinguished them from NECs (60%), though with great overlap. The expression of site-specific markers, p53, Rb1, and SST2 was similar in NETs G3 and NETs G1/G2, except for p53 and Rb1 which were abnormally expressed in 8% and 7% of liver metastases from NET G3 but not from NET G1/G2. NETs G3 were frequently referred as NECs (39%) but could be well distinguished from NECs by normal p53 (92% versus 21%) and Rb1 expression (93% versus 41%) expression. In conclusion, NETs G3 are frequently discovered as liver metastases from pancreatic or pulmonary primaries and are often misinterpreted as NEC. p53 and Rb1 are powerful markers in the distinction of NET G3 from NEC. Rarely, carcinomas from non-digestive, non-pulmonary organs with neuroendocrine features may present as NET G3.

[Ductal adenocarcinoma of the pancreas: subtypes and molecular pathology]

Ductal adenocarcinoma is the most common tumor of the pancreas. Although relatively rare, it poses one of the greatest oncological challenges because of its poor prognosis, which has so far only slightly improved. Progress has been made in the more precise classification and standardization of the morphological assessment. In the current WHO classification, prognostically relevant subtypes are clearly delimited among themselves and from ductal adenocarcinoma not otherwise specified (NOS). In the recent TNM classification, a size-based T‑category was introduced. Diagnostically, the histological assessment of the resection specimen is relatively easy; on the other hand, assessment of the fine-needle biopsy from the primary tumor or a liver metastasis is still difficult. The molecular stratification of ductal adenocarcinoma and the other pancreatic neoplasms has made great progress. This not only defined the genetics of tumor entities, but also identified the prognosis and biology of tumor groups on the basis of RNA expression patterns. The range of treatment could be expanded by targeted molecular therapies (especially for patients with BRCA1/2 germline mutations, NTRK- or NRG1-fusions, or oncogenic BRAF and PIK3CA mutations as well as tumors with microsatellite instability (MSI)), even if targeted therapies are currently only available for a minority of patients (<10%).

Mesenchymal/non-epithelial mimickers of neuroendocrine neoplasms with a focus on fusion gene-associated and SWI/SNF-deficient tumors

Mimickers of neuroendocrine neoplasms (NEN) include a number of important pitfall tumors. Here, we describe our experience with mesenchymal mimics of NENs to illustrate their spectrum and draw the attention particularly to a group of mesenchymal/non-epithelial neoplasms (MN) that combine epithelioid histology with neuroendocrine (NE-) features and peculiar genetic abnormalities. In a consultation series of 4498 cases collected between 2009 and 2021, 2099 neoplasms expressing synaptophysin and/or chromograninA were reviewed and analyzed. A total of 364 (18%) were diagnosed as non-NENs, while the remaining tumors were NEN. The group of mesenchymal/non-epithelial neoplasms with NE-features (MN-NE) included 31/364 (8%) cases. These mostly malignant neoplasms showed an epithelioid morphology. While all but one tumor expressed synaptophysin, mostly patchy, only 10/29 (34%) co-expressed chromograninA. A total of 13/31 (42%) of the MN-NE showed EWSR1-related gene fusions (6 Ewing sarcomas, 5 clear cell sarcomas, and 1 desmoplastic small round cell tumor, 1 neoplasm with FUS-CREM gene fusion) and 7 (23%) were SWI/SNF (SMARCB1 or SMARCA4)-deficient neoplasms. The remaining MN-NE included synovial sarcoma, sclerosing epithelioid mesenchymal neoplasm, melanoma, alveolar soft part sarcoma, solitary fibrous tumor, and chordoma. A total of 27/31 MN-NE were from the last 8 years, and 6 of them were located in the pancreas. Eleven MN-NE were initially diagnosed as neuroendocrine carcinomas (NECs). MN-NE with epithelioid features play an increasing role as mimickers of NECs. They mostly belong to tumors with gene fusions involving the EWSR1 gene, or with SWI/SNF complex deficiency. Synaptophysin expression is mostly patchy and chromograninA expression is infrequent in MN-NE of this series and data extracted from literature.

Bcl3 Couples Cancer Stem Cell Enrichment With Pancreatic Cancer Molecular Subtypes

BACKGROUND & AIMS

The existence of different subtypes of pancreatic ductal adenocarcinoma (PDAC) and their correlation with patient outcome have shifted the emphasis on patient classification for better decision-making algorithms and personalized therapy. The contribution of mechanisms regulating the cancer stem cell (CSC) population in different subtypes remains unknown.

METHODS

Using RNA-seq, we identified B-cell CLL/lymphoma 3 (BCL3), an atypical nf-κb signaling member, as differing in pancreatic CSCs. To determine the biological consequences of BCL3 silencing in vivo and in vitro, we generated bcl3-deficient preclinical mouse models as well as murine cell lines and correlated our findings with human cell lines, PDX models, and 2 independent patient cohorts. We assessed the correlation of bcl3 expression pattern with clinical parameters and subtypes.

RESULTS

Bcl3 was significantly down-regulated in human CSCs. Recapitulating this phenotype in preclinical mouse models of PDAC via BCL3 genetic knockout enhanced tumor burden, metastasis, epithelial to mesenchymal transition, and reduced overall survival. Fluorescence-activated cell sorting analyses, together with oxygen consumption, sphere formation, and tumorigenicity assays, all indicated that BCL3 loss resulted in CSC compartment expansion promoting cellular dedifferentiation. Overexpression of BCL3 in human PDXs diminished tumor growth by significantly reducing the CSC population and promoting differentiation. Human PDACs with low BCL3 expression correlated with increased metastasis, and BCL3-negative tumors correlated with lower survival and nonclassical subtypes.

CONCLUSIONS

We demonstrate that bcl3 impacts pancreatic carcinogenesis by restraining CSC expansion and by curtailing an aggressive and metastatic tumor burden in PDAC across species. Levels of BCL3 expression are a useful stratification marker for predicting subtype characterization in PDAC, thereby allowing for personalized therapeutic approaches.

mTORC1 and mTORC2 Converge on the Arp2/3 Complex to Promote KrasG12D-Induced Acinar-to-Ductal Metaplasia and Early Pancreatic Carcinogenesis

BACKGROUND & AIMS

Oncogenic KrasG12D induces neoplastic transformation of pancreatic acinar cells through acinar-to-ductal metaplasia (ADM), an actin-based morphogenetic process, and drives pancreatic ductal adenocarcinoma (PDAC). mTOR (mechanistic target of rapamycin kinase) complex 1 (mTORC1) and 2 (mTORC2) contain Rptor and Rictor, respectively, and are activated downstream of KrasG12D, thereby contributing to PDAC. Yet, whether and how mTORC1 and mTORC2 impact on ADM and the identity of the actin nucleator(s) mediating such actin rearrangements remain unknown.

METHODS

A mouse model of inflammation-accelerated KrasG12D-driven early pancreatic carcinogenesis was used. Rptor, Rictor, and Arpc4 (actin-related protein 2/3 complex subunit 4) were conditionally ablated in acinar cells to deactivate the function of mTORC1, mTORC2 and the actin-related protein (Arp) 2/3 complex, respectively.

RESULTS

We found that mTORC1 and mTORC2 are markedly activated in human and mouse ADM lesions, and cooperate to promote KrasG12D-driven ADM in mice and in vitro. They use the Arp2/3 complex as a common downstream effector to induce the remodeling the actin cytoskeleton leading to ADM. In particular, mTORC1 regulates the translation of Rac1 (Rac family small GTPase 1) and the Arp2/3-complex subunit Arp3, whereas mTORC2 activates the Arp2/3 complex by promoting Akt/Rac1 signaling. Consistently, genetic ablation of the Arp2/3 complex prevents KrasG12D-driven ADM in vivo. In acinar cells, the Arp2/3 complex and its actin-nucleation activity mediated the formation of a basolateral actin cortex, which is indispensable for ADM and pre-neoplastic transformation.

CONCLUSIONS

Here, we show that mTORC1 and mTORC2 attain a dual, yet nonredundant regulatory role in ADM and early pancreatic carcinogenesis by promoting Arp2/3 complex function. The role of Arp2/3 complex as a common effector of mTORC1 and mTORC2 fills the gap between oncogenic signals and actin dynamics underlying PDAC initiation.

Stroma composition and proliferative activity are related to therapy response in neoadjuvant treated pancreatic ductal adenocarcinoma

BACKGROUND

Tumor regression grading (TRG) based on histopathology is the main tool to assess therapy effects after neoadjuvant therapy (NAT) of pancreatic ductal adenocarcinoma (PDAC). However, reliable markers to distinguish therapy effects from pre-existing tumor features are lacking. The aim of this study was the characterization of PDAC after NAT, focusing on the stroma.

MATERIAL AND METHODS

Tissue samples from patients resected for PDAC after NAT (n=27) were analyzed. TRG was assessed using the Royal North Shore (RNS) system. Stromal composition was evaluated by Movat's stain. Immunohistochemistry (IH) for Ki-67 and five previously established stroma markers (alpha-Crystallin B, alpha-Smooth muscle actin (alpha-SMA), Neurotrophin-3 (NT-3), SPARC and Tenascin C) was also performed. Results were compared with therapy-naïve PDACs (n=10).

RESULTS

Most cases showed a moderate response (RNS 2; 74%), while 15% displayed a poor response (RNS 3), and 11% a good response (RNS 1). No complete response was observed. Poor regression was associated with mucin-rich stroma, while good regression was associated with collagen-rich stroma. Cases with poorer therapy response had significantly higher proliferation. Higher peritumoral staining intensity for alpha-SMA and Tenascin C also showed a trend towards an association with poor regression.

CONCLUSIONS

Similar to the stroma in therapy-naïve PDAC, the stroma of PDAC after NAT is heterogeneous. Distinguishing between desmoplastic stroma and therapy-induced fibrosis by single markers is not possible. Movat's pentachrome stain, IH for Ki-67, and to some extent for Tenascin C and alpha-SMA, can help detect poor histopathological response to NAT.

Multiparametric Modelling of Survival in Pancreatic Ductal Adenocarcinoma Using Clinical, Histomorphological, Genetic and Image-Derived Parameters

Rationale: Pancreatic ductal adenocarcinoma (PDAC) remains a tumor entity of exceptionally poor prognosis, and several biomarkers are under current investigation for the prediction of patient prognosis. Many studies focus on promoting newly developed imaging biomarkers without a rigorous comparison to other established parameters. To assess the true value and leverage the potential of all efforts in this field, a multi-parametric evaluation of the available biomarkers for PDAC survival prediction is warranted. Here we present a multiparametric analysis to assess the predictive value of established parameters and the added contribution of newly developed imaging features such as biomarkers for overall PDAC patient survival. Methods: 103 patients with resectable PDAC were retrospectively enrolled. Clinical and histopathological data (age, sex, chemotherapy regimens, tumor size, lymph node status, grading and resection status), morpho-molecular and genetic data (tumor morphology, molecular subtype, tp53, kras, smad4 and p16 genetics), image-derived features and the combination of all parameters were tested for their prognostic strength based on the concordance index (CI) of multivariate Cox proportional hazards survival modelling after unsupervised machine learning preprocessing. Results: The average CIs of the out-of-sample data were: 0.63 for the clinical and histopathological features, 0.53 for the morpho-molecular and genetic features, 0.65 for the imaging features and 0.65 for the combined model including all parameters. Conclusions: Imaging-derived features represent an independent survival predictor in PDAC and enable the multiparametric, machine learning-assisted modelling of postoperative overall survival with a high performance compared to clinical and morpho-molecular/genetic parameters. We propose that future studies systematically include imaging-derived features to benchmark their additive value when evaluating biomarker-based model performance.

Histological examination of explanted tissue-engineered bovine pericardium following heart valve repair

OBJECTIVES

Our goal was to present histopathological findings of human explants of a tissue-engineered bovine pericardium CardioCel (Admedus Regen Pty Ltd, Malaga, WA, Australia) used for heart valve repair in patients with congenital and acquired heart valve disease.

METHODS

Sixty patients underwent heart valve repair from May 2014 to November 2018 using CardioCel as a substitute for valve tissue. We identified 9 cases in which the CardioCel patch was explanted following valve repair and available for histomorphological analyses. CardioCel explants were evaluated histologically using haematoxylin and oeosin, Elastica van Gieson and immunohistochemical stains.

RESULTS

The indications for explantation were related to the CardioCel patch in 6 patients. Median time between the implantation and explantation was 242 (range 3-1247) days. We demonstrated a characteristic remodelling pattern with superficial coating of the tissue-engineered bovine pericardium by granulation tissue composed of histiocytes, few lymphocytes and fibrin. We had 2 cases with a multifocal nodular disruption, fragmentation and sclerosis of the decellularized collagen matrix with focal calcification after 795 and 1247 days in situ.

CONCLUSIONS

Our data suggest that the tissue-engineered CardioCel patch is initially tolerated in the valvular position in the majority of patients. However, we also experienced graft failures that showed degeneration with fragmentation of the collagen matrix and even 2 cases with focal calcification evident from the histopathological analysis. Further analyses of mid- and long-term performance are mandatory.

Post-neoadjuvant cellular dissociation grading based on tumour budding and cell nest size is associated with therapy response and survival in oesophageal squamous cell carcinoma

Background

Cellular Dissociation Grade (CDG) composed of tumour budding and cell nest size has been shown to independently predict prognosis in pre-therapeutic biopsies and primary resections of oesophageal squamous cell carcinoma (ESCC). Here, we aimed to evaluate the prognostic impact of CDG in ESCC after neoadjuvant therapy.

Methods

We evaluated cell nest size and tumour budding activity in 122 post-neoadjuvant ESCC resections, correlated the results with tumour regression groups and patient survival and compared the results with data from primary resected cases as well as pre-therapeutic biopsies.

Results

CDG remained stable when results from pre-therapeutic biopsies and post-therapeutic resections from the same patient were compared. CDG was associated with therapy response and a strong predictor of overall, disease-specific (DSS) and disease-free (DFS) survival in univariate analysis and—besides metastasis—remained the only significant survival predictor for DSS and DFS in multivariate analysis. Multivariate DFS hazard ratios reached 3.3 for CDG-G2 and 4.9 for CDG-G3 neoplasms compared with CDG-G1 carcinomas (p = 0.016).

Conclusions

CDG is the only morphology-based grading algorithm published to date, which in concert with regression grading, is able to contribute relevant prognostic information in the post-neoadjuvant setting of ESCC.

Ductal obstruction promotes formation of preneoplastic lesions from the pancreatic ductal compartment

Pancreatitis is a significant risk factor for pancreatic ductal adenocarcinoma (PDAC). Previous studies in mice have demonstrated that pancreatitis contributes to oncogenic Kras-driven carcinogenesis, probably initiated in acinar cells; however, oncogenic Kras alone or in combination with caerulein-induced pancreatitis is not sufficient in initiating PDAC from the ductal compartment. We thus introduced ductal obstruction - which induces a more severe form of pancreatitis - by pancreatic ductal ligation in mice harbouring oncogenic Kras. This induced a particular phenotype with highly proliferative nonmucinous cells with nuclear atypia. Around these lesions, there was a significant proliferation of activated fibroblasts and infiltration of immune cells, corroborating the pathological features of preneoplastic lesions. Lineage-tracing experiments revealed that these preneoplastic cells derived from two distinctive cellular sources: acinar and ductal cells. Phenotypic characterisation revealed that the duct-derived preneoplastic lesions show a high proliferative potential with persistent activation of tumour-promoting inflammatory pathways while the acinar-derived ones were less proliferative with persistent p53 activation. Furthermore, the duct-derived preneoplastic cells have a particularly high nuclear-to-cytoplasmic ratio. These data demonstrate that ductal obstruction promotes preneoplastic lesion formation from the pancreatic ductal compartment.

Spatial intratumor heterogeneity in uveal melanoma: Tumor cell subtypes with a presumed invasive potential exhibit a particular epigenetic staining reaction

Cancer evolves from a combination of genetic and epigenetic abnormalities resulting in aberrant gene expression profiles as well as altered epigenomic patterns. Epigenetic alterations such as DNA methylation and histone modification play an important role in tumorigenesis. While in the pathobiology of uveal melanoma (UM) genetic changes have been well characterized, there is growing evidence suggesting that epigenetic changes are also involved. We investigated whether epigenetic modifications (global levels of histone acetylation, DNA methylation, ubiquitination) are detectable in UM tissues compared to healthy controls with respect to inter- and intratumoral heterogeneity. Formalin-fixed paraffin-embedded tissues of primary UM (n = 15), UM metastasis (n = 13), and control choroid (n = 12) were immunohistochemically investigated by two ophthalmic pathologists for global levels of histone acetylation (Histone 3 acetylation, H3Ac; Histone 4 acetylation, H4Ac), DNA methylation (5-methylcytosine, 5-MeC; 5'-hydroxymethylcytosine, 5-hMeC), global ubiquitination (UBC) as well as Ubiquityl-Histone H2A (H2Aub). The nuclear staining intensity of primary tumors, metastases and control choroids was evaluated using a score from 0 to 3, which was multiplied with the percentage of stained cells (score from 0 to 4). The control choroid and the choroid next to the tumor showed a more intense nuclear staining than the primary tumor tissue. The choroid next to the tumor was stained less than the control choroid. The nuclear staining intensity in the tumor was comparable to that in the metastases. The tumor tissue itself often exhibited a heterogeneous staining pattern, as nuclei in the tumor center were less intensely stained than in the periphery. Cells with a presumed invasive potential (extraocular extension, growth along emissary canals) showed also an intense staining reaction. Although no prognostically relevant pattern of global epigentic markers could be identified, our results suggest that epigenetic changes play a role in UM pathogenesis and metastasis. In particular the staining reaction of tumor cell subtypes with a presumed invasive potential warrants further attention. The role of epigenetically relevant interactions with the tumor micromilieu should be further investigated as immune cells are predominantly located in the tumor periphery which showed a different staining intensity than the tumor center. However, as considerable epigenetic diversity exists in primary tumors, studies on biopsy tissue are not recommended for the immunohistochemical investigation of epigenetic markers.

Levels of the Autophagy-Related 5 Protein Affect Progression and Metastasis of Pancreatic Tumors in Mice

BACKGROUND AND AIMS

Cells in pancreatic ductal adenocarcinoma (PDAC) undergo autophagy, but its effects vary with tumor stage and genetic factors. We investigated the consequences of varying levels of the autophagy related 5 (Atg5) protein on pancreatic tumor formation and progression.

METHODS

We generated mice that express oncogenic Kras in primary pancreatic cancer cells and have homozygous disruption of Atg5 (A5;Kras) or heterozygous disruption of Atg5 (A5^+/-;Kras), and compared them with mice with only oncogenic Kras (controls). Pancreata were analyzed by histology and immunohistochemistry. Primary tumor cells were isolated and used to perform transcriptome, metabolome, intracellular calcium, extracellular cathepsin activity, and cell migration and invasion analyses. The cells were injected into wild-type littermates, and orthotopic tumor growth and metastasis were monitored. Atg5 was knocked down in pancreatic cancer cell lines using small hairpin RNAs; cell migration and invasion were measured, and cells were injected into wild-type littermates. PDAC samples were obtained from independent cohorts of patients and protein levels were measured on immunoblot and immunohistochemistry; we tested the correlation of protein levels with metastasis and patient survival times.

RESULTS

A5^+/-;Kras mice, with reduced Atg5 levels, developed more tumors and metastases, than control mice, whereas A5;Kras mice did not develop any tumors. Cultured A5^+/-;Kras primary tumor cells were resistant to induction and inhibition of autophagy, had altered mitochondrial morphology, compromised mitochondrial function, changes in intracellular Ca²⁺ oscillations, and increased activity of extracellular cathepsin L and D. The tumors that formed in A5^+/-;Kras mice contained greater numbers of type 2 macrophages than control mice, and primary A5^+/-;Kras tumor cells had up-regulated expression of cytokines that regulate macrophage chemoattraction and differentiation into M2 macrophage. Knockdown of Atg5 in pancreatic cancer cell lines increased their migratory and invasive capabilities, and formation of metastases following injection into mice. In human PDAC samples, lower levels of ATG5 associated with tumor metastasis and shorter survival time.

CONCLUSIONS

In mice that express oncogenic Kras in pancreatic cells, heterozygous disruption of Atg5 and reduced protein levels promotes tumor development, whereas homozygous disruption of Atg5 blocks tumorigenesis. Therapeutic strategies to alter autophagy in PDAC should consider the effects of ATG5 levels to avoid the expansion of resistant and highly aggressive cells.

Loss of TLR3 and its downstream signaling accelerates acinar cell damage in the acute phase of pancreatitis

BACKGROUND

Acute pancreatitis is accompanied by acinar cell damage releasing potential toll-like receptor 3 (TLR3) ligands. So far, TLR3 is known as a pattern recognition receptor in the immune signaling cascade triggering a type I interferon response. In addition, TLR3 signaling contributes to programmed cell death through the activation of caspase 8. However, the functional role of TLR3 and its downstream toll-like receptor adaptor molecule 1 (TICAM1) in the inflamed pancreas is unknown.

METHODS

To uncover the role of TLR3 signaling in acute pancreatitis, we induced a cerulein-mediated pancreatitis in Tlr3 and Ticam1 knockout (KO) mice and in wildtype animals. The exocrine damage was determined by blood serum analysis and histological examination. Immunohistochemistry, gene expression and immunoblot analysis were conducted to study TLR3 function.

RESULTS

After the induction of an acute pancreatitis, wildtype mice showed a high endosomal TLR3 expression in acinar cells. In comparison to wildtype and Ticam1 KO mice, Tlr3 KO mice exhibited the highest severity of pancreatitis with an increased NF-κB activation and elevated expression of the pro-inflammatory cytokines Il6 and Tnf, although the amount of infiltrating immune cells was unaffected. Additionally, we detected a strong elevation of acinar cell necrosis and reduced levels of cleaved caspase 8 in Tlr3 and Ticam1 KO mice.

CONCLUSIONS

TLR3 and its downstream adaptor TICAM1 are important mediators of acinar cell damage in acute pancreatitis. They possess a critical role in programmed cell death and our data suggest that TLR3 signaling controls the onset and severity of acute pancreatitis.

Pancreatic neuroendocrine carcinomas reveal a closer relationship to ductal adenocarcinomas than to neuroendocrine tumors G3

Pancreatic neuroendocrine carcinoma is a rare aggressive tumor commonly harboring TP53 and RB1 alterations and lacking neuroendocrine-related genetic changes such as mutations in MEN1 and ATRX/DAXX. Little is known about its genetic profile with regard to that of pancreatic ductal adenocarcinoma. We therefore conducted a detailed genetic study in 12 pancreatic neuroendocrine carcinomas of large cell (n = 9) and small cell type (n = 3) using massive parallel sequencing applying a 409-gene panel on an Ion Torrent system. The genetic data were compared with known data of pancreatic ductal adenocarcinoma and correlated with exocrine lineage marker expression. A similar analysis was performed in 11 pancreatic neuroendocrine tumors G3. Neuroendocrine carcinomas harbored 63 somatic mutations in 45 different genes, affecting most commonly TP53 (8/12 cases), KRAS (5/12 cases), and RB1 (loss of expression with or without deletion in 4/12 cases). Five carcinomas had both TP53 and KRAS mutations. Neuroendocrine tumors G3 only shared singular mutations in 5 different genes with neuroendocrine carcinomas, including TP53, CDKN2A, ARID1A, LRP1B, and APC, affecting 5 different cases. Most KRAS-positive neuroendocrine carcinomas also expressed MUC1 (4/5) and carcinoembryonic antigen (3/5) as markers of ductal differentiation. Our data indicate that almost half of the pancreatic neuroendocrine carcinomas are genetically and phenotypically related to pancreatic ductal adenocarcinoma, and might therefore respond to chemotherapies targeting the latter carcinomas.

Appendiceal goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid are genetically distinct from primary colorectal-type adenocarcinoma of the appendix

The appendix gives rise to goblet cell carcinoids, which represent special carcinomas with distinct biological and histological features. Their genetic background and molecular relationship to colorectal adenocarcinoma is largely unknown. We therefore performed a next-generation sequencing analysis of 25 appendiceal carcinomas including 11 goblet cell carcinoids, 7 adenocarcinomas ex-goblet cell carcinoid, and 7 primary colorectal-type adenocarcinomas, using a modified Colorectal Cancer specific Panel comprising 32 genes linked to colorectal and neuroendocrine tumorigenesis. The mutational profiles of these neoplasms were compared with those of conventional adenocarcinomas, mixed adenoneuroendocrine carcinomas, and neuroendocrine carcinomas of the colorectum. In addition, a large-scale pan-cancer sequencing panel covering 409 genes was applied to selected cases of goblet cell carcinoid/adenocarcinoma ex-goblet cell carcinoid (n=2, respectively). Mutations in colorectal cancer-related genes (eg, TP53, KRAS, APC) were rare to absent in both, goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid, but frequent in primary colorectal-type adenocarcinomas of the appendix. Additional large-scale sequencing of selected goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid revealed mutations in Wnt-signaling-associated genes (USP9X, NOTCH1, CTNNA1, CTNNB1, TRRAP). These data suggest that appendiceal goblet cell carcinoids and adenocarcinomas ex-goblet cell carcinoid constitute a morphomolecular entity, histologically and genetically distinct from appendiceal colorectal-type adenocarcinomas and its colorectal counterparts. Altered Wnt-signaling associated genes, apart from APC, may act as potential drivers of these neoplasms. The absence of KRAS/NRAS mutations might render some of these tumors eligible for anti-EGFR directed therapy regimens.

Dynamic landscape of pancreatic carcinogenesis reveals early molecular networks of malignancy

OBJECTIVE

The initial steps of pancreatic regeneration versus carcinogenesis are insufficiently understood. Although a combination of oncogenic Kras and inflammation has been shown to induce malignancy, molecular networks of early carcinogenesis remain poorly defined.

DESIGN

We compared early events during inflammation, regeneration and carcinogenesis on histological and transcriptional levels with a high temporal resolution using a well-established mouse model of pancreatitis and of inflammation-accelerated Kras^G12D-driven pancreatic ductal adenocarcinoma. Quantitative expression data were analysed and extensively modelled in silico.

RESULTS

We defined three distinctive phases-termed inflammation, regeneration and refinement-following induction of moderate acute pancreatitis in wild-type mice. These corresponded to different waves of proliferation of mesenchymal, progenitor-like and acinar cells. Pancreas regeneration required a coordinated transition of proliferation between progenitor-like and acinar cells. In mice harbouring an oncogenic Kras mutation and challenged with pancreatitis, there was an extended inflammatory phase and a parallel, continuous proliferation of mesenchymal, progenitor-like and acinar cells. Analysis of high-resolution transcriptional data from wild-type animals revealed that organ regeneration relied on a complex interaction of a gene network that normally governs acinar cell homeostasis, exocrine specification and intercellular signalling. In mice with oncogenic Kras, a specific carcinogenic signature was found, which was preserved in full-blown mouse pancreas cancer.

CONCLUSIONS

These data define a transcriptional signature of early pancreatic carcinogenesis and a molecular network driving formation of preneoplastic lesions, which allows for more targeted biomarker development in order to detect cancer earlier in patients with pancreatitis.

Pancreatic Ductal Adenocarcinoma Subtyping Using the Biomarkers Hepatocyte Nuclear Factor-1A and Cytokeratin-81 Correlates with Outcome and Treatment Response

Purpose: Pancreatic ductal adenocarcinoma (PDAC) is associated with a dismal prognosis and poor therapeutic response to current chemotherapy regimens in unselected patient populations. Recently, it has been shown that PDAC may be stratified into functionally and therapeutically relevant molecular subgroups and that some of these subtypes can be recapitulated by IHC for KRT81 [quasi-mesenchymal (QM)/squamous/basal-like] and HNF1A (non-QM, overlap with exocrine/ADEX subtype).Experimental Design: We validated the different outcome of the HNF1A/KRT81 PDAC subtypes in two independent cohorts of surgically treated patients and examined the treatment response to chemotherapy in a third cohort of unresectable patients. The first two cohorts included 262 and 130 patients, respectively, and the third independent cohort comprised advanced-stage PDAC patients who were treated with either FOLFIRINOX (64 patients) or gemcitabine (61 patients).Results: In both cohorts with resected PDAC, the HNF1A-positive subtype showed the best, the KRT81-positive subtype the worst, and the double-negative subtype an intermediate survival (P < 0.013 and P < 0.009, respectively). In the chemotherapy cohort, the survival difference between the double-negative and the HNF1A-positive subtype was lost, whereas the dismal prognosis of KRT81-positive PDAC patients was retained (P < 0.021). Patients with a KRT81-positive subtype did not benefit from FOLFIRINOX therapy, whereas those with HNF1A-positive tumors responded better compared with gemcitabine-based treatment (P < 0.038).Conclusions: IHC stratification recapitulating molecular subtypes of PDAC using HNF1A and KRT81 is associated with significantly different outcomes and responses to chemotherapy. These results may pave the way toward future pretherapeutic biomarker-based stratification of PDAC patients. Clin Cancer Res; 24(2); 351-9. ©2017 AACR.

pT but not pN stage of the 8th TNM classification significantly improves prognostication in pancreatic ductal adenocarcinoma

The UICC TNM (tumour-node-metastasis) staging system for pancreatic ductal adenocarcinoma (PDAC) has been a matter of debate over decades because survival prediction based on T stages was weak and unreliable. To improve staging, the recently published 8th TNM edition (2016) introduced a conceptually completely changed strictly size-based T staging system and a refined N stage for PDAC. To investigate the clinical value of the novel TNM classification, we compared the prognostic impact of pT and pN stage between the 7th and 8th edition in two well-characterised independent German PDAC cohorts from different decades, including a total number of 523 patients. Former UICC T staging (7th edition 2009) resulted in a clustering of pT3 cases (72% and 85% of cases per cohort, respectively) and failed to show significant prognostic differences between the four stages in one of the investigated cohorts (p = 0.074). Application of the novel size-based T stage system resulted in a more equal distribution of cases between the four T categories with a predominance of pT2 tumours (65% and 60% of cases). The novel pT staging algorithm showed greatly improved discriminative power with highly significant overall differences between the four pT stages in both investigated cohorts in univariate and multivariate analyses (p < 0.001, each). In contrast, no prognostic differences were observed between the recently introduced pN1 and pN2 categories in both cohorts (p = 0.970 and p = 0.061). pT stage of resected PDAC patients according to the novel UICC staging protocol (8th edition) significantly improves patient stratification, whereas introduction of an extended N stage protocol does not demonstrate high clinical relevance in our cohorts.

Extended RAS analysis and correlation with overall survival in advanced pancreatic cancer

BACKGROUND

Mutations in the KRAS gene can be detected in about 70-90% of pancreatic cancer (PC) cases. Whether these mutations have a prognostic or predictive value remains elusive. Furthermore, the clinical relevance of the extended RAS (KRAS+NRAS) mutational status is unclear in PC.

METHODS

We prospectively defined a PC patient population who received erlotinib-free chemotherapy regimens. A statistically significant difference between KRAS wild-type and KRAS mutated tumours in at least 160 patients in this population would support the assumption of a rather prognostic role of KRAS.

RESULTS

One hundred and seventy-eight tumour samples were collected from prospective clinical studies and successfully analysed for the extended RAS status: 37 tumours were KRAS wild-type (21%), whereas 141 (79%) carried a KRAS mutation; 132 of these mutations were found in KRAS exon 2 (74%), whereas only 9 mutations (5%) were detected in KRAS exon 3. Within KRAS exon 4 and NRAS exons 2-4, no mutations were apparent. There was no significant difference in overall survival for KRAS wild-type vs mutant patients (9.9 vs 8.3 months, P=0.70).

CONCLUSIONS

Together with the results of the AIO-PK-0104-trial, the present analysis supports the notion that KRAS mutation status is rather predictive than prognostic in advanced PC.

Impact of NKT Cells and LFA-1 on Liver Regeneration under Subseptic Conditions

Background

Activation of the immune system in terms of subseptic conditions during liver regeneration is of paramount clinical importance. However, little is known about molecular mechanisms and their mediators that control hepatocyte proliferation. We sought to determine the functional role of immune cells, especially NKT cells, in response to partial hepatectomy (PH), and to uncover the impact of the integrin lymphocyte function-associated antigen-1 (LFA-1) on liver regeneration in a subseptic setting.

Methods

Wild-type (WT) and LFA-1^-/- mice underwent a 2/3 PH and low-dose lipopolysaccharid (LPS) application. Hepatocyte proliferation, immune cell infiltration, and cytokine profile in the liver parenchyma were determined.

Results

Low-dose LPS application after PH results in a significant delay of liver regeneration between 48h and 72h, which is associated with a reduced number of CD3⁺ cells within the regenerating liver. In absence of LFA-1, an impaired regenerative capacity was observed under low-dose LPS application. Analysis of different leukocyte subpopulations showed less CD3⁺NK1.1⁺ NKT cells in the liver parenchyma of LFA-1^-/- mice after PH and LPS application compared to WT controls, while CD3^-NK1.1⁺ NK cells markedly increased. Concordantly with this observation, lower levels of NKT cell related cytokines IL-12 and IL-23 were expressed in the regenerating liver of LFA-1^-/- mice, while the expression of NK cell-associated CCL5 and IL-10 was increased compared to WT mice.

Conclusion

A subseptic situation negatively alters hepatocyte proliferation. Within this scenario, we suggest an important impact of NKT cells and postulate a critical function for LFA-1 during processes of liver regeneration.

Periostin and tumor-stroma interactions in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-associated mortality globally. Interactions of the cancer cells with the tumor microenvironment are essential carcinogenic features for the majority of solid tumors, such as pancreatic cancer. The present study investigated the role of stromal activation in NSCLC and analyzed the surgical specimens of 93 patients by immunohistochemistry with regard to periostin (an extracellular matrix protein), α-smooth muscle actin (α-SMA; a marker of myofibroblasts) and cluster of differentiation 31 (CD31; a marker of endothelial cells), and the activated stroma index. There was a trend towards reduced overall survival for patients with high periostin expression (hazard ratio, 1.80; 95% confidence interval, 0.99–3.27; P=0.050). No significant correlations with overall survival were identified for α-SMA (P=0.930), CD31 (P=0.923), collagen (P=0.441) or the activated stroma index (P=0.706). In a multivariable analysis, the histological tumor subtype, tumor stage, lymph node involvement and resection status were independent prognostic factors in NSCLC, but none of the investigated immunohistochemical markers were prognostic factors. Thus, the tumor microenvironment and stroma activation did not prove to be of prognostic relevance for lung cancer, as it has been previously described for pancreatic cancer. Other markers of the microenvironment of NSCLC may be of higher prognostic value, pointing towards tumor-type specific effects.

Structure-Preserving Color Normalization and Sparse Stain Separation for Histological Images

Staining and scanning of tissue samples for microscopic examination is fraught with undesirable color variations arising from differences in raw materials and manufacturing techniques of stain vendors, staining protocols of labs, and color responses of digital scanners. When comparing tissue samples, color normalization and stain separation of the tissue images can be helpful for both pathologists and software. Techniques that are used for natural images fail to utilize structural properties of stained tissue samples and produce undesirable color distortions. The stain concentration cannot be negative. Tissue samples are stained with only a few stains and most tissue regions are characterized by at most one effective stain. We model these physical phenomena that define the tissue structure by first decomposing images in an unsupervised manner into stain density maps that are sparse and non-negative. For a given image, we combine its stain density maps with stain color basis of a pathologist-preferred target image, thus altering only its color while preserving its structure described by the maps. Stain density correlation with ground truth and preference by pathologists were higher for images normalized using our method when compared to other alternatives. We also propose a computationally faster extension of this technique for large whole-slide images that selects an appropriate patch sample instead of using the entire image to compute the stain color basis.

A subset of metastatic pancreatic ductal adenocarcinomas depends quantitatively on oncogenic Kras/Mek/Erk-induced hyperactive mTOR signalling

OBJECTIVE

Oncogenic Kras-activated robust Mek/Erk signals phosphorylate to the tuberous sclerosis complex (Tsc) and deactivates mammalian target of rapamycin (mTOR) suppression in pancreatic ductal adenocarcinoma (PDAC); however, Mek and mTOR inhibitors alone have demonstrated minimal clinical antitumor activity.

DESIGN

We generated transgenic mouse models in which mTOR was hyperactivated either through the Kras/Mek/Erk cascade, by loss of Pten or through Tsc1 haploinsufficiency. Primary cancer cells were isolated from mouse tumours. Oncogenic signalling was assessed in vitro and in vivo, with and without single or multiple targeted molecule inhibition. Transcriptional profiling was used to identify biomarkers predictive of the underlying pathway alterations and of therapeutic response. Results from the preclinical models were confirmed on human material.

RESULTS

Reduction of Tsc1 function facilitated activation of Kras/Mek/Erk-mediated mTOR signalling, which promoted the development of metastatic PDACs. Single inhibition of mTOR or Mek elicited strong feedback activation of Erk or Akt, respectively. Only dual inhibition of Mek and PI3K reduced mTOR activity and effectively induced cancer cell apoptosis. Analysis of downstream targets demonstrated that oncogenic activity of the Mek/Erk/Tsc/mTOR axis relied on Aldh1a3 function. Moreover, in clinical PDAC samples, ALDH1A3 specifically labelled an aggressive subtype.

CONCLUSIONS

These results advance our understanding of Mek/Erk-driven mTOR activation and its downstream targets in PDAC, and provide a mechanistic rationale for effective therapeutic matching for Aldh1a3-positive PDACs.

Pancreas-specific activation of mTOR and loss of p53 induce tumors reminiscent of acinar cell carcinoma

Background

Pancreatic acinar cell carcinoma (ACC) is a rare tumor entity with an unfavorable prognosis. Recent whole-exome sequencing identified p53 mutations in a subset of human ACC. Activation of the mammalian target of rapamycin (mTOR) pathway is associated with various pancreatic neoplasms. We thus aimed at analyzing whether activation of mTOR with a concomitant loss of p53 may initiate ACC.

Methods

We generated transgenic mouse models in which mTOR was hyperactivated through pancreas-specific, homozygous tuberous sclerosis 1 (Tsc1) deficiency, with or without deletion of p53 (Tsc1^-/- and Tsc1^-/-; p53^-/-). Activity of mTOR signaling was investigated using mouse tissues and isolated murine cell lines. Human ACC specimens were used to corroborate the findings from the transgenic mouse models.

Results

Hyperactive mTOR signaling in Tsc1^-/- mice was not oncogenic but rather induced a near-complete loss of the pancreatic acinar compartment. Acinar cells were lost as a result of apoptosis which was associated with p53 activation. Concomitantly, ductal cells were enriched. Ablation of p53 in Tsc1-deficient mice prevented acinar cell death but promoted formation of acinar cells with severe nuclear abnormalities. One out of seven Tsc1^-/-; p53^-/- animals developed pancreatic tumors showing a distinctive tumor morphology, reminiscent of human ACC. Hyperactive mTOR signaling was also detected in a subset of human ACC.

Conclusion

Hyperactive mTOR signaling combined with loss of p53 in mice induces tumors similar to human ACC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0483-1) contains supplementary material, which is available to authorized users.

Potential role of Th17 cells in the pathogenesis of type 2 autoimmune pancreatitis

Th17 cells have been shown to play an important role in the pathogenesis of a variety of autoimmune diseases. The aim of this study was to investigate the potential role of Th17 cells in autoimmune pancreatitis (AIP). Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to determine gene expression of the signature cytokines of Th17 cells IL-17A and IL-21 and of the Th17 lineage-specific transcription factor retinoic acid receptor-related orphan receptor C (RORC) in human tissue specimens of AIP, classical chronic pancreatitis (CP), and normal pancreas (NP). Infiltrating immune cells were characterized by immunohistochemistry (IHC). Gene expression of IL-17A, IL-21, and RORC were found to be significantly increased in AIP. Accordingly, the number of Th17 cells was significantly increased in AIP compared to NP or CP. Both gene expression analysis and IHC revealed a clear difference between type 1 and 2 AIP. In the periductal compartment of type 2 AIP, which is characterized by granulocytic epithelial lesions (GELs), the number of infiltrating Th17 cells and neutrophilic granulocytes was significantly increased compared to type 1 AIP. Our data suggest that Th17 cells play a role in the pathogenesis of AIP, in particular of type 2 AIP. Cross-talk between Th17 cells and neutrophilic granulocytes mediated via IL-17A may be a potential mechanism by which neutrophils are recruited to the duct and acinar cells with subsequent destruction, a process that is pathognomonic for type 2 AIP.

Model Matters: Differences in Orthotopic Rat Hepatocellular Carcinoma Physiology Determine Therapy Response to Sorafenib

PURPOSE

Preclinical model systems should faithfully reflect the complexity of the human pathology. In hepatocellular carcinoma (HCC), the tumor vasculature is of particular interest in diagnosis and therapy. By comparing two commonly applied preclinical model systems, diethylnitrosamine induced (DEN) and orthotopically implanted (McA) rat HCC, we aimed to measure tumor biology noninvasively and identify differences between the models.

EXPERIMENTAL DESIGN

DEN and McA tumor development was monitored by MRI and PET. A slice-based correlation of imaging and histopathology was performed. Array CGH analyses were applied to determine genetic heterogeneity. Therapy response to sorafenib was tested in DEN and McA tumors.

RESULTS

Histologically and biochemically confirmed liver damage resulted in increased (18)F-fluorodeoxyglucose (FDG) PET uptake and perfusion in DEN animals only. DEN tumors exhibited G1-3 grading compared with uniform G3 grading of McA tumors. Array comparative genomic hybridization revealed a highly variable chromosomal aberration pattern in DEN tumors. Heterogeneity of DEN tumors was reflected in more variable imaging parameter values. DEN tumors exhibited lower mean growth rates and FDG uptake and higher diffusion and perfusion values compared with McA tumors. To test the significance of these differences, the multikinase inhibitor sorafenib was administered, resulting in reduced volume growth kinetics and perfusion in the DEN group only.

CONCLUSIONS

This work depicts the feasibility and importance of in depth preclinical tumor model characterization and suggests the DEN model as a promising model system of multifocal nodular HCC in future therapy studies.

Next-generation sequencing reveals novel differentially regulated mRNAs, lncRNAs, miRNAs, sdRNAs and a piRNA in pancreatic cancer

Background

Previous studies identified microRNAs (miRNAs) and messenger RNAs with significantly different expression between normal pancreas and pancreatic cancer (PDAC) tissues. Due to technological limitations of microarrays and real-time PCR systems these studies focused on a fixed set of targets. Expression of other RNA classes such as long intergenic non-coding RNAs or sno-derived RNAs has rarely been examined in pancreatic cancer. Here, we analysed the coding and non-coding transcriptome of six PDAC and five control tissues using next-generation sequencing.

Results

Besides the confirmation of several deregulated mRNAs and miRNAs, miRNAs without previous implication in PDAC were detected: miR-802, miR-2114 or miR-561. SnoRNA-derived RNAs (e.g. sno-HBII-296B) and piR-017061, a piwi-interacting RNA, were found to be differentially expressed between PDAC and control tissues. In silico target analysis of miR-802 revealed potential binding sites in the 3′ UTR of TCF4, encoding a transcription factor that controls Wnt signalling genes. Overexpression of miR-802 in MiaPaCa pancreatic cancer cells reduced TCF4 protein levels. Using Massive Analysis of cDNA Ends (MACE) we identified differential expression of 43 lincRNAs, long intergenic non-coding RNAs, e.g. LINC00261 and LINC00152 as well as several natural antisense transcripts like HNF1A-AS1 and AFAP1-AS1. Differential expression was confirmed by qPCR on the mRNA/miRNA/lincRNA level and by immunohistochemistry on the protein level.

Conclusions

Here, we report a novel lncRNA, sncRNA and mRNA signature of PDAC. In silico prediction of ncRNA targets allowed for assigning potential functions to differentially regulated RNAs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0358-5) contains supplementary material, which is available to authorized users.

Sorafenib inhibits macrophage-induced growth of hepatoma cells by interference with insulin-like growth factor-1 secretion

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) associated macrophages accelerate tumor progression by growth factor release. Therefore, tumor-associated macrophages (TAM) and their initiated signaling cascades are potential therapeutic targets. Aiming at understanding anticancer effects of systemic HCC therapy, we investigated the impact of sorafenib on macrophage function, focusing on macrophage-related growth factor secretion.

METHODS

Macrophage markers, cytokine and growth factor release were investigated in CSF-1 (M1) or GMCSF (M2) maturated monocyte-derived macrophages. Macrophages were treated with sorafenib (1.2-5.0 μg/ml) and culture supernatants were transferred to hepatoma cell cultures to assess growth propagation. Insulin-like growth factor (IGF) signaling was blocked with NVP-AEW541 to confirm the role of IGF-1 in macrophage-driven hepatoma cell propagation. Macrophage activation was followed by ELISA of serum soluble mCD163 in sorafenib-treated patients with HCC.

RESULTS

Alternative macrophages (M2), which showed higher IGF-1 (p=0.022) and CD163 mRNA (p=0.032) expression compared to classical macrophages (M1), increased hepatoma growth. This effect was mediated by M2-conditioned culture media. In turn, sorafenib lowered mCD163 and IGF-1 release by M2 macrophages, which decelerated M2 macrophage driven HuH7 and HepG2 proliferation by 47% and 64%, respectively. IGF-receptor blockage with NVP-AEW541 reduced growth induction by M2-conditioned culture media in a dose dependent manner. A transient mCD163 reduction during sorafenib treatment indicated a coherent M2 macrophage inhibition in patients with HCC.

CONCLUSIONS

Sorafenib alters macrophage polarization, reduces IGF-1-driven cancer growth in vitro and partially inhibits macrophage activation in vivo. Thus macrophage modulation might contribute to the anti-cancer activity of sorafenib. However, more efficient macrophage-directed therapies are required.

Pathology of pancreatic ductal adenocarcinoma: Facts, challenges and future developments

Despite major improvements concerning its diagnosis and treatment, pancreatic ductal adenocarcinoma (PDAC) remains an aggressive disease with an extremely poor prognosis. Pathology, as interface discipline between basic and clinical medicine, has substantially contributed to the recent developments and has laid the basis for further progress. The definition and classification of precursor lesions of PDAC and their molecular characterization is a fundamental step for the potential identification of biomarkers and the development of imaging methods for early detection. In addition, by integrating findings in humans with the knowledge acquired through the investigation of transgenic mouse models for PDAC, a new model for pancreatic carcinogenesis has been proposed and partially validated in individuals with genetic predisposition for PDAC. The introduction and validation of a standardized system for pathology reporting based on the axial slicing technique has shown that most pancreatic cancer resections are R1 resections and that this is due to inherent anatomical and biological properties of PDAC. This standardized assessment of prognostic relevant parameters represents the basis for the successful conduction of multicentric studies and for the interpretation of their results. Finally, recent studies have shown that distinct molecular subtypes of PDAC exist and are associated with different prognosis and therapy response. The prospective validation of these results and the integration of molecular analyses in a comprehensive pathology report in the context of individualised cancer therapy represent a major challenge for the future.

pERK, pAKT and p53 as tissue biomarkers in erlotinib-treated patients with advanced pancreatic cancer: a translational subgroup analysis from AIO-PK0104

Background

The role of pERK, pAKT and p53 as biomarkers in patients with advanced pancreatic cancer has not yet been defined.

Methods

Within the phase III study AIO-PK0104 281 patients with advanced pancreatic cancer received an erlotinib-based 1^st-line regimen. Archival tissue from 153 patients was available for central immunohistochemistry staining for pERK, pAKT and p53. Within a subgroup analysis, biomarker data were correlated with efficacy endpoints and skin rash using a Cox regression model.

Results

Fifty-five out of 153 patients were classified as pERK^low and 98 patients as pERK^high; median overall survival (OS) was 6.2 months and 5.7 months, respectively (HR 1.29, p = 0.16). When analysing pERK as continuous variable, the pERK score was significantly associated with OS (HR 1.06, 95% CI 1.0-1.12, p = 0.05). Twenty-one of 35 patients were pAKT^low and 14/35 pAKT^high with a corresponding median OS of 6.4 months and 6.8 months, respectively (HR 1.03, p = 0.93). Four out of 50 patients had a complete loss of p53 expression, 20 patients a regular expression and 26 patients had tumors with p53 overexpression. The p53 status had no impact on OS (p = 0.91); however, a significant improvement in progression-free survival (PFS) (6.0 vs 1.8 months, HR 0.24, p = 0.02) and a higher rate of skin rash (84% vs 25%, p = 0.02) was observed for patients with a regular p53 expression compared to patients with a complete loss of p53.

Conclusion

pERK expression may have an impact on OS in erlotinib-treated patients with advanced pancreatic cancer; p53 should be further investigated for its potential role as a predictive marker for PFS and skin rash.

Trial registration

NCT00440167 (registration date: February 22, 2007).

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-624) contains supplementary material, which is available to authorized users.

Intraductal papillary neoplasms of the bile duct: stepwise progression to carcinoma involves common molecular pathways

Intraductal papillary neoplasms of the bile duct are still poorly characterized regarding (1) their molecular alterations during the development to invasive carcinomas, (2) their subtype stratification and (3) their biological behavior. We performed a multicenter study that analyzed these issues in a large European cohort. Intraductal papillary neoplasms of the bile duct from 45 patients were graded and subtyped using mucin markers and CDX2. In addition, tumors were analyzed for common oncogenic pathways, and the findings were correlated with subtype and grade. Data were compared with those from 22 extra- and intrahepatic cholangiocarcinomas. Intraductal papillary neoplasms showed a development from preinvasive low- to high-grade intraepithelial neoplasia to invasive carcinoma. Molecular and immunohistochemical analysis revealed mutated KRAS, overexpression of TP53 and loss of p16 in low-grade intraepithelial neoplasia, whereas loss of SMAD4 was found in late phases of tumor development. Alterations of HER2, EGFR, β-catenin and GNAS were rare events. Among the subtypes, pancreato-biliary (36%) and intestinal (29%) were the most common, followed by gastric (18%) and oncocytic (13%) subtypes. Patients with intraductal papillary neoplasm of the bile duct showed a slightly better overall survival than patients with cholangiocarcinoma (hazard ratio (cholangiocarcinoma versus intraductal papillary neoplasm of the bile duct): 1.40; 95% confidence interval: 0.46-4.30; P=0.552). The development of biliary intraductal papillary neoplasms of the bile duct follows an adenoma-carcinoma sequence that correlates with the stepwise activation of common oncogenic pathways. Further large trials are needed to investigate and verify the finding of a better prognosis of intraductal papillary neoplasms compared with conventional cholangiocarcinoma.

Claudin 18.2 is a target for IMAB362 antibody in pancreatic neoplasms

The majority of pancreatic neoplasms are characterized by a generally lethal progress within a short period of time after primary diagnosis and the mortality of patients is expected to increase further. Due to lack of efficient screening programs and moderate response to treatments, novel compounds for treatment are needed. We investigated the CLDN18.2 expression in affected patients as in vitro feasibility study for a potential treatment with the novel antibody IMAB362. Therefore, we analyzed the expression of CLDN18.2 in normal pancreatic tissues (N = 24), primary lesions (N = 202), metastases (N = 84) and intra-individually matched samples (N = 48) of patients with pancreatic ductal adenocarcinoma (PDAC), neuroendocrine neoplasia (NEN) and acinar cell carcinoma. A standardized method for evaluation by immunohistochemistry was developed. The specific staining was evaluated by two independent raters and analysis of staining intensities (range 0-3+) and relative proportions of tumor cells were performed. One hundred three (59.2%) samples of primary PDAC were found positive. The vast majority of positive samples were characterized to highly express CLDN18.2: 54.6% (N = 95) with staining intensities of ≥ 2+. NEN were positive in 20% of cases (all ≥ 2+). Metastases of pancreatic neoplasms were also frequently found positive with comparable high rates (69.4% of lymph node and 65.7% of liver metastases). The rate of CLDN18.2 positivity is high in pancreatic neoplasms whereby the expression is not limited to the primaries but is also maintained upon metastasis. Thus, a considerable number of patients with pancreatic neoplasms would be in principle eligible for a CLDN18.2-targeting approach.

Selective requirement of PI3K/PDK1 signaling for Kras oncogene-driven pancreatic cell plasticity and cancer

Oncogenic Kras activates a plethora of signaling pathways, but our understanding of critical Ras effectors is still very limited. We show that cell-autonomous phosphoinositide 3-kinase (PI3K) and 3-phosphoinositide-dependent protein kinase 1 (PDK1), but not Craf, are key effectors of oncogenic Kras in the pancreas, mediating cell plasticity, acinar-to-ductal metaplasia (ADM), and pancreatic ductal adenocarcinoma (PDAC) formation. This contrasts with Kras-driven non-small cell lung cancer, where signaling via Craf, but not PDK1, is an essential tumor-initiating event. These in vivo genetic studies together with pharmacologic treatment studies in models of human ADM and PDAC demonstrate tissue-specific differences of oncogenic Kras signaling and define PI3K/PDK1 as a suitable target for therapeutic intervention specifically in PDAC.

[Pathology and classification of intraductal papillary mucinous neoplasms of the pancreas]

Intraductal papillary mucinous neoplasms (IPMN) are precursor lesions of ductal adenocarcinoma of the pancreas and one of the most common cystic entities in this organ. Branch and main duct types are further distinguished based on the tumor localization. An additional classification is based on the predominant architecture and immunohistochemical profile with four prognostic relevant subtypes, gastric, intestinal, pancreato-biliary and oncocytic. This review provides an overview about the malignant potential of the different subtypes and the prognosis of associated invasive tumors and gives recommendations for the pathological assessment of resection specimens with IPMNs.

Clinical features and relapse rates after surgery in type 1 autoimmune pancreatitis differ from type 2: a study of 114 surgically treated European patients

BACKGROUND

At the recent consensus conference on autoimmune pancreatitis (AIP) in Honolulu, we presented preliminary data from our study of surgically treated AIP patients. Our data strongly supported the separation of AIP into type 1 and type 2. Our study is based on a total of 114 surgically treated European AIP patients. Our aims were to elucidate serum IgG4 elevation, other organ involvement, relapse of disease, steroid treatment and diabetes after surgery in 114 surgically treated European AIP patients.

METHODS

88 pancreaticoduodenectomies, 22 left-sided resections and 4 total pancreatectomies were examined. All cases were graded for granulocytic epithelial lesions, IgG4-positive cells, storiform fibrosis, phlebitis and eosinophilic granulocytes. Follow-up data were obtained from 102/114 patients, mean follow-up was 5.3 years.

RESULTS

Histologically, 63 (55.3%) of the 114 patients fulfilled the criteria of type 1 AIP, while 51 (44.7%) patients fulfilled the criteria of type 2 AIP. Type 1 AIP patients were older and more often males than type 2 AIP patients. Elevation of serum IgG4, involvement of extrapancreatic organs, disease relapse, systemic steroid treatment and diabetes after surgery were noted more often in type 1 AIP, while inflammatory bowel disease (IBD) was observed mainly in type 2 AIP.

CONCLUSIONS

Histological typing of AIP is clinically important because type 1 AIP is part of the IgG4-related disease and type 2 AIP is associated with IBD. Our data also show that relapse of disease and steroid treatment after surgery occur more frequently in type 1 than in type 2 AIP.

Definition of microscopic tumor clearance (r0) in pancreatic cancer resections

To date, curative resection is the only chance for cure for patients suffering from pancreatic ductal adenoacarcinoma (PDAC). Despite low reported rates of microscopic tumor infiltration (R1) in most studies, tumor recurrence is a common finding in patients with PDAC and contributes to extremely low long-term survival rates. Lack of international definition of resection margins and of standardized protocols for pathological examination lead to high variation in reported R1 rates. Here we review recent studies supporting the hypothesis that R1 rates are highly underestimated in certain studies and that a microscopic tumor clearance of at least 1 mm is required to confirm radicality and to serve as a reliable prognostic and predictive factor.

NPC-db, a Niemann-Pick type C disease gene variation database

Niemann-Pick type C (NPC) disease is a rare autosomal-recessive lysosomal storage disease typically accompanied by progressive impairment of nervous system and liver function. Biochemically, the disorder presents with an inhibited egress of cholesterol and glycosphingolipids from endosomal and lysosomal compartments in neuronal and nonneuronal cells. In the majority of NPC patients, mutations in the NPC1 gene can be identified. About 5% of patients show mutations in the NPC2 gene. Many different mutations can cause NPC disease and multiple variants not associated with the disease are known in both genes. A continuously updated collection of gene variants is lacking to date and only limited information is available on genotype-phenotype correlation. We have created the NPC disease gene variation database (NPC-db; http://npc.fzk.de; last accessed 24 October 2007). This database aims to provide a comprehensive overview of the sequence variants in NPC1 and NPC2, including information on their functional consequences and associated haplotypes. Moreover, genotype data and clinical information from individual NPC patients provide information on the impact of functional variants. NPC-db addresses professionals and nonprofessionals dealing with NPC disease on a clinical, diagnostic, research, or personal basis. The user is encouraged to search contents and submit novel information, thereby contributing to generate a valuable open-access tool that will allow a better understanding of the molecular and clinical details of NPC disease.