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Molecular events occurring in stepwise progression from pre-malignant lesions (pancreatic intraepithelial neoplasia; PanIN) to the development of pancreatic ductal adenocarcinoma (PDAC) are poorly understood. Thus, characterization of early PanIN lesions may reveal markers that can help in diagnosing PDAC at an early stage and allow understanding the pathology of the disease. We performed the molecular and histological assessment of patient-derived PanINs, tumor tissues and pancreas from mouse models with PDAC (KC mice that harbor K-RAS mutation in pancreatic tissue), where we noted marked upregulation of gastrokine (GKN) proteins. To further understand the role of gastrokine proteins in PDAC development, GKN-deficient KC mice were developed by intercrossing gastrokine-deficient mice with KC mice. Panc-02 (pancreatic cancer cells of mouse origin) were genetically modified to express GKN1 for further in vitro and in vivo analysis. Our results show that gastrokine proteins were absent in healthy pancreas and invasive cancer, while its expression was prominent in low-grade PanINs. We could detect these proteins in pancreatic juice and serum of KC mice. Furthermore, accelerated PanIN and tumor development were noted in gastrokine deficient KC mice. Loss of gastrokine 1 protein delayed apoptosis during carcinogenesis leading to the development of desmoplastic stroma while loss of gastrokine 2 increased the proliferation rate in precursor lesions. In summary, we identified gastrokine proteins in early pancreatic precursor lesions, where gastrokine proteins delay pancreatic carcinogenesis., Oncogene, 41 (10), ISSN:0950-9232, ISSN:1476-5594

BACKGROUND AND AIM Acute decompensation and death have been observed in patients with acute hepatitis E virus (HEV) infection and preexisting liver cirrhosis. However, the clinical, laboratory and histological features need to be fully characterised. METHODS Some of us recently described the histological presentation of hepatitis E in a large panel of liver tissue specimens. Here, we conducted a case-control study to investigate the clinical and laboratory features of the subset of patients with HEV-related acute-on-chronic liver failure (ACLF) and death. Each patient was matched to three control patients with histologically confirmed severe alcoholic hepatitis based on sex, age, total bilirubin, INR, serum creatinine and MELD score on admission. RESULTS Of 5 patients who died in a context of HEV-related ACLF, 3 (60%) were male and the median age was 66 years (range 51–76). Median alanine aminotransferase (ALT) at presentation was 2610 U/l (range 705–3134) and aspartate aminotransferase (AST) 2818 U/l (range 1176–8611). Liver function was heavily altered in all patients. Histological analyses revealed steatohepatitis on a background of cirrhosis, suggestive of an alcoholic or nonalcoholic origin. Based on histopathology, alcoholic hepatitis was initially suspected in two patients and corticosteroid treatment was initiated. Ribavirin was started in four patients. Median time from hospitalisation to death was 17 days (range 6–25 days). AST levels in patients with HEV-related ACLF were significantly higher as compared to the matched patients with severe alcoholic hepatitis. CONCLUSION Typical histopathological features of viral hepatitis may be absent in ACLF caused by HEV infection. HEV infection should be sought in acute decompensation of cirrhosis and ACLF even in the absence of histological changes suggesting viral infection.

Hepatocellular carcinoma (HCC) can have viral or non-viral causes1–5. Non-alcoholic steatohepatitis (NASH) is an important driver of HCC. Immunotherapy has been approved for treating HCC, but biomarker-based stratification of patients for optimal response to therapy is an unmet need6,7. Here we report the progressive accumulation of exhausted, unconventionally activated CD8+PD1+ T cells in NASH-affected livers. In preclinical models of NASH-induced HCC, therapeutic immunotherapy targeted at programmed death-1 (PD1) expanded activated CD8+PD1+ T cells within tumours but did not lead to tumour regression, which indicates that tumour immune surveillance was impaired. When given prophylactically, anti-PD1 treatment led to an increase in the incidence of NASH–HCC and in the number and size of tumour nodules, which correlated with increased hepatic CD8+PD1+CXCR6+, TOX+, and TNF+ T cells. The increase in HCC triggered by anti-PD1 treatment was prevented by depletion of CD8+ T cells or TNF neutralization, suggesting that CD8+ T cells help to induce NASH–HCC, rather than invigorating or executing immune surveillance. We found similar phenotypic and functional profiles in hepatic CD8+PD1+ T cells from humans with NAFLD or NASH. A meta-analysis of three randomized phase III clinical trials that tested inhibitors of PDL1 (programmed death-ligand 1) or PD1 in more than 1,600 patients with advanced HCC revealed that immune therapy did not improve survival in patients with non-viral HCC. In two additional cohorts, patients with NASH-driven HCC who received anti-PD1 or anti-PDL1 treatment showed reduced overall survival compared to patients with other aetiologies. Collectively, these data show that non-viral HCC, and particularly NASH–HCC, might be less responsive to immunotherapy, probably owing to NASH-related aberrant T cell activation causing tissue damage that leads to impaired immune surveillance. Our data provide a rationale for stratification of patients with HCC according to underlying aetiology in studies of immunotherapy as a primary or adjuvant treatment., In hepatocellular carcinoma driven by non-alcoholic steatohepatitis, aberrant T cell activation and impaired immune surveillance seem to make hepatocellular carcinoma less responsive to anti-PD1 or anti-PDL1 immunotherapy.

Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis, for which treatment options, especially the long-term management, are limited. The only therapy that has been established and accepted so far is corticosteroids, but the relapse rate is significant. In the current study, we discern the effector mechanisms of targeted LTβR pathway inhibition using LTβR-Ig. Furthermore, the efficacy of LTβR-Ig therapy is compared with the depletion of immune cell subsets (CD4+ and CD20+), which are suggested to play a pathological role in AIP development. Three well-established mouse models of AIP were used to examine treatment efficacies and mechanisms. Tg(Ela1-Lta,b) mice represent a genetic model, in which AIP develops spontaneously. In MRL/Mp and IL-10−/− mice, AIP is induced by repeated polyinosinic:polycytidylic acid injection. Mice with AIP were treated with anti-CD20, anti-CD4 mAbs, or targeted LTβR-Ig. LTβR-Ig and anti-CD20 treatment led to significant improvement of AIP, including a decrease in autoantibody production and pancreatic inflammation in Tg(Ela1-Lta,b) and IL-10−/− mice. The molecular mechanism of this beneficial effect possibly involves the downregulation of Stat3 and noncanonical NF-κb activation. Anti-CD4 treatment reduced Th1 and Th2 signature but did not alleviate AIP. Additionally, in contrast to anti-CD20 or anti-CD4 treatments, blocking LTβR signaling disrupted tertiary lymphoid organs in all three models. We demonstrate that treatment with LTβR-Ig or anti-CD20 Ab alleviated murine AIP. LTβR-Ig treatment for AIP was effective in both lymphotoxin-dependent and lymphotoxin-independent AIP models, possibly because of its dual anti-inflammatory and antiautoimmune mechanisms.

Immune checkpoint inhibitory (ICI) therapy represents a novel approach in a variety of cancers, with impressive survival benefit. With ICIs, however, a new spectrum of immune related adverse events (irAE) including life threatening hypohysitis has emerged. This autopsy study aimed to investigate inflammatory cells, PD-1 and PD-L1 expression in cases of patients who developed hypophysitis and involvement of other organs. We analysed 6 patients, who were treated with ICIs and developed hypophysitis. Two received an additional MAP-kinase inhibitor, MEK-inhibitor and cytotoxic chemotherapy. Besides the pituitary gland, all investigated adrenal glands (5/5) were affected; three cases had other organs involved (liver (2/6), thyroid (2/6), lung (1/6), myocardium (1/6), colon (1/6). The inflammatory cells of involved organs were further specified and PD1 and PDL-1 expression was analyzed using immunohistochemistry. We observed that patients treated with ICIs alone showed T-cell predominant lymphocytic infiltrates, whereas patients receiving additional therapies demonstrated an increase in B- and T-lymphocytes. Surprisingly, the dominant inflammatory population was not T-cell, but type 2 macrophages. CD25 positive T-regs were sparse or absent. Our study suggests that T cell activation is only partially responsible for irAE. ICI therapy interaction with CTLA-4, PD-1 and PDL-1 in type 2 macrophages appears to result in disturbance of their control. Furthermore, depletion of T-regs seems to contribute significantly. Our findings with simultaneous pituitary and adrenal gland involvement underlines the systemic involvement as well as the importance of monitoring cortisol levels to avoid potentially life threatening hypocortisolism.

Infection with the hepatitis E virus (HEV) is one of the main causes of acute hepatitis worldwide. Given that, the histopathology of hepatitis E is relatively poorly characterized, and it is unclear what exactly determines its remarkable variability. The aim of our study was a systematic analysis of hepatitis E histology, especially with regard to the clinical setting. Fifty-two liver samples (48 biopsies, 1 liver explant, 3 autopsy livers) from 41 patients with molecularly proven hepatitis E (28 HEV genotype (gt) 3, three gt 1, one gt 4 and 9 undetermined gt) were systematically evaluated for 33 histopathologic features. Following one approach, the biopsies were assigned to one of five generic histologic patterns. In another approach, they were subjected to hierarchical clustering. We found that 23/41 (56%) patients were immunocompromised, whereas 18 (44%) had no known immunosuppression. Five patients (12%) had pre-existing liver disease (LD). The histopathologic spectrum ranged from almost normal to acute, chronic, and steato-hepatitis to subtotal necrosis, and was thus distributed across all five generic patterns. Hierarchical clustering, however, identified three histopathologic clusters (C1-C3), which segregated along the immune status and pre-existing LD: C1 comprised mostly patients with pre-existing LD; histology mainly reflected the respective LD without pointing to the additional hepatitis E. C2 comprised mostly immunocompetent patients; histology mainly displayed florid hepatitis. C3 comprised mostly immunocompromised patients; histology mainly displayed smoldering hepatitis. Accordingly, C1-C3 differed markedly with respect to their clinical and histopathologic differential diagnoses. Hierarchical clustering suggests three groups with distinct histopathologies, indicating biologically different manifestations of hepatitis E. The association of histopathologic changes with the patient's immune status and pre-existing LD plausibly explains the diversity of hepatitis E histopathology, and suggests that these factors are the crucial underlying determinants. We expect our results to improve patient management by guiding the clinico-pathologic diagnosis of hepatitis E.

Activated pancreatic stellate cells (PSCs) play a central role in the tumor stroma of pancreatic ductal adenocarcinoma (PDAC). Given the limited availability of patient-derived PSCs from PDAC, immortalized PSC cell lines of murine and human origin have been established, however, it is not elucidated whether differences in species, organ disease status, donor age, and immortalization alter the PSC phenotype and behavior compared to that of patient-derived primary PSC cultures. Therefore, a panel of commonly used PSC cultures was examined for important phenotypical and functional features: three primary cultures from human PDAC, one primary from normal human pancreas, and three immortalized (one from human, two from murine pancreas). Growth rate was considerably lower in primary PSCs from human PDAC. Basal collagen synthesis varied between the PSC cultures, and TGF-&beta, stimulation increased collagen synthesis only in non-immortalized cultures. Differences in secretome composition were observed along with a divergence in the DNA synthesis, migration, and response to gemcitabine of PDAC cell lines that were grown in conditioned medium from the various PSC cultures. The findings reveal considerable differences in features and functions that are key to PSCs and in the interactions with PDAC. These observations may be relevant to researchers when selecting the most appropriate PSC culture for their experiments.

We describe a highly unusual case of metastatic melanoma in a 61-year-old female that manifested as a single groin lymph node metastasis accompanied by two distinct, subcutaneous sarcomatoid tumors on the same leg, without evidence of a primary tumor. Characterization encompassed extensive immunohistochemical staining as well as next-generation sequencing (NGS). The lymph node metastasis showed obvious features of melanoma. The two subcutaneous lesions, however, were morphologically and immunohistochemically consistent with high-grade myxofibrosarcoma and soft tissue mixed tumor, respectively. All three lesions were BRAF wild-type and found to harbor an identical NRAS p.Q61R mutation. Metachronic intestinal metastases, showing intermingled conventional and sarcomatoid morphology, as well as an identical genetic phenotype, corroborated these findings. The concordant genetic profile provided evidence of biphasic sarcomatoid transdifferentiation of melanoma. Interestingly, the lack of genetic heterogeneity between the three morphologically distinct tumors suggests factors other than genetic mutations to be involved in melanoma transdifferentiation.

Infection with the hepatitis E virus (HEV) is globally seen a leading cause of hepatitis. Now increasingly recognized also in industrialized countries, hepatitis E constitutes a significant health problem worldwide. The patient's immune status determines the clinical course and histopathology of hepatitis E. In immunocompetent patients, hepatitis E usually follows an asymptomatic or subclinical course, but may also present with acute hepatitis. In contrast, immunocompromised patients may develop chronic hepatitis, and patients with preexisting liver diseases are at risk for liver decompensation with potentially fatal outcome. Whereas pathologists only occasionally encounter liver biopsies from immunocompetent individuals with hepatitis E, they are more likely exposed to biopsies from patients with preexisting liver disease or immunocompromised individuals. Histopathologic hallmarks of hepatitis E in immunocompetent patients comprise lobular disarray, lobular, and portal inflammation, as well as hepatocyte necrosis of varying extend and regeneration. Thus, it is similar to acute non-E viral hepatitis, yet further differential diagnoses include autoimmune hepatitis and drug-induced liver injury. Histopathologic findings of hepatitis E in preexisting liver disease are determined by the underlying pathology, but may be more severe. Histopathologic presentation of hepatitis E in immunocompromised patients is highly variable, ranging from minimal active hepatitis to chronic hepatitis with severe activity and progressive fibrosis. Taken together, the variability of the histologic features depending on the clinical context and the overlap with other liver diseases make the histopathologic diagnosis of hepatitis E challenging. Immunohistochemistry for HEV open reading frame 2 protein and molecular testing for HEV RNA are useful tissue-based ancillary tools.

A 60-year-old man who abused corticosteroids developed thoracic-distribution zoster. Varicella zoster virus (VZV) DNA was found in non-healing skin 3 months later. He died suddenly 2 months later. Skin was ulcerated and necrotic. VZV was widespread in organs and arteries, particularly coronary arteries and aorta, with VZV vasculopathy in the posterior cerebral artery.

Despite existing vaccination strategies targeting TRP-2, its function is not yet fully understood. TRP-2 is an enzyme involved in melanin biosynthesis and therefore discussed as a differentiation antigen. However, in mice Trp-2 was shown to be expressed in melanocyte stem cells of the hair follicle and therefore also considered as an indicator of stemness. A proper understanding of the TRP-2 function is crucial, considering a vaccination targeting cells with stemness properties would be highly effective in contrast to a therapy targeting differentiated melanoma cells. Analysing over 200 melanomas including primaries, partly matched metastases and patients’ cell cultures we show that TRP-2 is correlated with Melan A expression and decreases with tumor progression. In mice it is expressed in differentiated melanocytes as well as in stem cells. Furthermore, we identify a TRP-2 negative, proliferative, hypoxia related cell subpopulation which is significantly associated with tumor thickness and diseases progression. Patients with a higher percentage of those cells have a less favourable tumor specific survival. Our findings underline that TRP-2 is a differentiation antigen, highlighting the importance to combine TRP-2 vaccination with other strategies targeting the aggressive undifferentiated hypoxia related subpopulation.