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Background & Aims: Cystic fibrosis (CF) is considered a multisystemic disorder in which CF‐associated liver disease (CFLD) is the third most common cause of mortality. Currently, no effective treatment is available for CFLD because its pathophysiology is still unclear. Interestingly, CFLD exhibits identical vascular characteristics as non‐cirrhotic portal hypertension, recently classified as porto‐sinusoidal vascular disorders (PSVD). Methods: Since endothelial cells (ECs) are an important component in PSVD, we performed single‐cell RNA sequencing (scRNA‐seq) on four explant livers from CFLD patients to identify differential endothelial characteristics which could contribute to the disease. We comprehensively characterized the endothelial compartment and compared it with publicly available scRNA‐seq datasets from cirrhotic and healthy livers. Key gene signatures were validated ex vivo on patient tissues. Results: We found that ECs from CF liver explants are more closely related to healthy than cirrhotic patients. In CF patients we also discovered a distinct population of liver sinusoidal ECs—coined CF LSECs—upregulating genes involved in the complement cascade and coagulation. Finally, our immunostainings further validated the predominant periportal location of CF LSECs. Conclusions: Our work showed novel aspects of human liver ECs at the single‐cell level thereby supporting endothelial involvement in CFLD, and reinforcing the hypothesis that ECs could be a driver of PSVD. Therefore, considering the vascular compartment in CF and CFLD may help developing new therapeutic approaches for these diseases. [ABSTRACT FROM AUTHOR]

The identification of gene fusions has become an integral part of soft tissue and bone tumour diagnosis. We investigated the added value of targeted RNA‐based sequencing (targeted RNA‐seq, Archer FusionPlex) to our current molecular diagnostic workflow of these tumours, which is based on fluorescence in situ hybridisation (FISH) for the detection of gene fusions using 25 probes. In a series of 131 diagnostic samples targeted RNA‐seq identified a gene fusion, BCOR internal tandem duplication or ALK deletion in 47 cases (35.9%). For 74 cases, encompassing 137 FISH analyses, concordance between FISH and targeted RNA‐seq was evaluated. A positive or negative FISH result was confirmed by targeted RNA‐seq in 27 out of 49 (55.1%) and 81 out of 88 (92.0%) analyses, respectively. While negative concordance was high, targeted RNA‐seq identified a canonical gene fusion in seven cases despite a negative FISH result. The 22 discordant FISH‐positive analyses showed a lower percentage of rearrangement‐positive nuclei (range 15–41%) compared to the concordant FISH‐positive analyses (>41% of nuclei in 88.9% of cases). Six FISH analyses (in four cases) were finally considered false positive based on histological and targeted RNA‐seq findings. For the EWSR1 FISH probe, we observed a gene‐dependent disparity (p = 0.0020), with 8 out of 35 cases showing a discordance between FISH and targeted RNA‐seq (22.9%). This study demonstrates an added value of targeted RNA‐seq to our current diagnostic workflow of soft tissue and bone tumours in 19 out of 131 cases (14.5%), which we categorised as altered diagnosis (3 cases), added precision (6 cases), or augmented spectrum (10 cases). In the latter subgroup, four novel fusion transcripts were found for which the clinical relevance remains unclear: NAB2::NCOA2, YAP1::NUTM2B, HSPA8::BRAF, and PDE2A::PLAG1. Overall, targeted RNA‐seq has proven extremely valuable in the diagnostic workflow of soft tissue and bone tumours. [ABSTRACT FROM AUTHOR]

Cytokeratin 5 is a marker of basal molecular subtypes of muscle‐invasive bladder cancer (MIBC), which correlates with worse overall survival compared to luminal subtypes. Our observations have not confirmed CK5 as a marker of high‐grade (HG) disease in Ta non‐muscle‐invasive bladder cancer (NMIBC). Therefore, to understand the basal‐luminal immunohistochemistry profile in Ta NMIBC, we performed immunohistochemistry for CK5, P40, P63 (basal), GATA3 and CK20 (luminal) and studied the correlation with HG and clinical outcome in 109 patients with Ta NMIBC. HG and low‐grade (LG) diseases were scored in each patient. Four different CK5 patterns were evaluated: absent (median 41.3%), normal (72.5%), rising (84.4%) and full thickness (23.9%). The median percentage of GATA3 was 100%. HG disease and CK5 expression and rising CK5 pattern had a significant inverse correlation, whereas HG disease and CK20 expression had a significant positive correlation. We also found a significant inverse correlation between CK5 expression and CK20 expression. Quantitative PCR confirmed that the presence of CK5 correlated with up‐regulation of CK5 RNA. None of the markers could differentiate patients with regard to clinical outcome. Our results suggest a role for CK5 and CK20 in differentiating between LG and HG disease in Ta NMIBC. [ABSTRACT FROM AUTHOR]

The article presents a case study of a 69-year-old woman diagnosed with anaplastic lymphoma kinase (ALK)-positive large-cell neuroendocrine carcinoma (LCNEC). It mentions that the patient was treated with crizotinib and underwent cholecystectomy for acute cholecystitis. It notes that the tumour shows a phenotypic variation.

Aims The incidence of ductal carcinoma in situ ( DCIS) has increased since the introduction of screening mammography. Recurrence prediction is still not accurate, and could be improved by identifying additional prognostic markers. Periductal stroma actively participates in early breast cancer progression. Therefore, the aim of this study was to explore the prognostic potential of stromal characteristics in DCIS. Methods and results Histopathological features and hormone receptor/ HER2 status were analysed in a first cohort of 65 cases of DCIS with a median follow-up of 112 months. Cox regression analysis revealed that myxoid stromal architecture was significantly associated with increased ipsilateral locoregional recurrence ( P = 0.015). Next, we performed immunohistochemical screening of nine stromal proteins in a second cohort of 82 DCIS cases, and correlated their expression with stromal architecture. Because reduced stromal decorin expression correlated most strongly with myxoid stroma ( P < 0.001), it was selected for further analysis in the first cohort. Patients with reduced periductal decorin expression had a higher risk of recurrence ( P = 0.008). Furthermore, HER2 overexpression was significantly associated with invasive but not with in situ recurrence ( P = 0.007). Conclusions Periductal myxoid stroma and reduced periductal decorin expression seem to be prognostic for overall ipsilateral locoregional recurrence in DCIS, whereas HER2 expression might be a more specific biomarker for invasive recurrence. [ABSTRACT FROM AUTHOR]

Fanconi anemia ( FA) is an inherited bone marrow failure syndrome due to defective DNA inter-strand cross-link repair. Hematopoietic stem cell transplantation ( HSCT) is curative for pancytopenia, but may not prevent the development of non-hematological malignancies. We describe a 26-year-old male patient with FA and Marfan syndrome who in 1994 underwent successful HSCT with bone marrow stem cells from his human leukocyte antigen ( HLA)-identical sister. In 2006, three lesions in the liver were detected and resected. The three lesions all showed activation of the β-catenin pathway and were histologically characterized by a highly differentiated steatotic hepatocellular carcinoma ( HCC) with remnants of the underlying adenoma from which it arose, a hepatocellular adenoma with foci of well-differentiated HCC, and a cholestatic adenoma. Risk factors for the emergence of HCC included FA itself, the use of androgens for a period of 3 years preceding HSCT and toxicity of the conditioning regimen. Because of the danger of developing additional HCC, liver transplantation was proposed, taking into consideration that immunosuppression would increase the risk of other malignancies. By using part of the liver of the sister, who already acted as bone marrow donor 13 years earlier, immunosuppression could be avoided. Liver transplantation was performed in 2007 without complication. Five years after liver transplantation the patient is doing well. This case is twofold special being the first case reporting FA co-occurring with Marfan syndrome and being the first reported case of FA treated for HCC by liver transplantation from a HLA-identical sibling donor without the use of immunosuppression. [ABSTRACT FROM AUTHOR]

The upper lamina propria (ULP) area of interstitial cells (IC) in bladder has been studied for more than a decade in several species including human beings. Nevertheless there is still lack of uniformity in terminology of this cell layer. The aim of the present study was to add new data to the morphological and immunohistochemical phenotype of these cells and to find out whether this phenotype is changed in bladders from patients with neurogenic detrusor overactivity (NDO) and bladder pain syndrome (BPS). Bladder tissue was obtained from a control group and from patients with NDO and BPS. Samples were processed for morphology, electron microscopy and immunohistochemistry. A morphological and immunohistochemical phenotype for the ULP IC was assessed and changes in this phenotype were looked for in samples from patients with NDO and BPS. The ULP IC were characterized ultrastructurally by the presence of actin filaments with densifications, many caveolae and abundant rough endoplasmic reticulum (RER); on immunohistochemistry ULP IC were immunoreactive for α-sma, vimentin, CD10 and podoplanin and categorized as interstitial Cajal-like cells (ICLC). In NDO and BPS bladders we found a phenotypical shift towards a fibroblastic phenotype which was even more pronounced in the NDO group. In both groups there was also an increased presence in ULP lymphocytes. The ULP area in the human bladder contains a population of ICLC with distinct ultrastructural morphology and immunohistochemical phenotype. Their unique α-sma+/desmin-/CD34- phenotype allows studying this population in various bladder disorders. In bladders form patients with BPS and NDO, we observed these ULP ICLC to shift towards a fibroblast phenotype. [ABSTRACT FROM AUTHOR]

HCV replicates in liver via an intermediate negative strand RNA. To study the relevance of HCV genome replication, quantitative strand-specific HCV real-time RT-PCR assays were developed and applied to livers explanted because of end-stage cirrhosis. The assays have broad ranges of determination and a high reproducibility and accuracy. Analysis of five different samples showed an even distribution of HCV genomes in four livers. Hepatic concentrations of positive (PS)- and negative (NS)-strand RNA did correlate with each other, with PS/NS ratios ranging between 3 and 340. Hepatic concentrations of HCV-PS or -NS RNA did not correlate with serum HCV-RNA levels or with genotypes. A high HCV envelope-2 protein expression correlated with a low NS concentration. HCV-PS and -NS levels, E2 protein expression and genotype did not correlate with biochemical tests or with histological changes in the explanted liver, but the ratio NS/PS, a marker of viral replication, correlated with the severity of the recurrent post-transplant hepatitis caused by HCV. This suggests the existence of an extra-hepatic location of HCV with comparable viral replication rate being responsible for the infection of the newly transplanted liver. J. Med. Virol. 81:1569-1575, 2009. © 2009 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Background: Hepatocellular carcinoma (HCC) responds poorly to chemotherapy owing to multidrug resistance (MDR). Recent studies showed that part of HCC could be of progenitor cell origin. Because some MDR-conferring transporters [multidrug resistance-associated protein 1 (MRP1), MDR1, MRP3 and breast cancer resistance protein (BCRP)] are expressed in hepatic progenitor cells (HPCs), expression in HCC might reflect a progenitor cell origin and provide the tumour cells with a MDR phenotype. Methods: The transcriptional profile of transporter genes was assessed in 139 HCCs earlier subjected to global gene expression analysis. In addition, we performed real-time reverse transcriptase-polymerase chain reaction and immunohistochemistry for MRP1, MRP3, MDR1, BCRP and biliary/HPC markers keratin 7 and/or keratin 19 (K7/K19) on an independent set of 23 HCCs and surrounding liver. Results: Micro-array analysis showed that MRP1 was the only transporter with increased mRNA levels in HCC compared with the surrounding tissue. MRP1 mRNA levels were significantly higher in HCCs with poor survival and the ‘hepatoblast subtype’ of HCC, thought to be derived from HPCs. In 11 of 23 HCCs of the independent set, we found a diffuse protein expression of MRP1 compared with negative hepatocytic expression observed in normal (surrounding) hepatocytes. MRP1 was expressed in K19+ non-neoplastic HPCs and K19+ tumour cells. In addition, MRP3 and BCRP were expressed in K7/K19+ tumour cells. MRP1 expression was high in poorly differentiated HCCs, large tumours (>7 cm) and microvascular invasive tumours. Conclusions: MRP1 correlated with K19 mRNA and protein expression in two independent series of HCC. In addition, MRP1 was, together with MRP3 and BCRP, colocalized with K7/K19 in the tumour. Therefore, MRP1 expression could be a reflection of the HPC origin of this subgroup of HCCs and may result in an aggressive tumour phenotype. [ABSTRACT FROM AUTHOR]

Aim: Hepatoblastoma (HB), the most common pediatric malignant liver tumor, is treated with chemotherapy to facilitate surgical resection. Previous studies suggest that HB acquires chemoresistance via increased expression of multidrug resistance protein 1 (MDR1, ABCC1). There is no well established evidence that this also occurs in the clinical setting and little is known about the effects of chemotherapeutic treatments on HB in situ. Methods: Clinical and histopathological features and expression patterns of ABC transporters in diagnostic needle biopsies from 7 HBs taken before chemotherapy were compared with those in surgically resected tumors. To understand the mechanism s leading to chemoresistance we also investigated the involvement of hypoxia on protein expression and functional activity of drug transporters (BCRP and MDR1) in cultures of HepG2 human HB cells. Results: We found that chemotherapeutical treatment of HBs led to an increased expression of the breast cancer resistance protein (BCRP, ABCG2) in all patients studied. There was no change in the expression pattern of MDR1 or other ABC transporters. Chemotherapy-induced specific vascular abnormalities associated with areas of necrosis and fibrosis were seen in all cases, suggesting tumor hypoxia. The observations of increased BCRP expression in hypoxic areas of three-dimensional HepG2 aggregates and the enhanced BCRP function in monolayer cultures of HepG2 cells under hypoxic conditions, support a role for hypoxia in enhanced BCRP expression. Conclusions: Chemotherapeutical treatment of HB leads to vascular alterations that modify the tumor microenvironment, and increased BCRP expression in which hypoxia might play a role. No evidence was found for upregulation of MDR1 in HBs as suggested from previous experimental studies. [ABSTRACT FROM AUTHOR]

Background/Aims: Meckel syndrome is an autosomal-recessive disease characterized by a combination of renal cysts, anomalies of the central nervous system, polydactyly and ductal plate malformations (DPM), which are hepatic anomalies consisting of excessive and abnormal foetal biliary structures. Among the genomic loci associated with Meckel syndrome, mutations in four genes were recently identified. These genes code for proteins associated with primary cilia and are possibly involved in cell differentiation. The aim of the present work was to investigate the formation of the primary cilia and the differentiation of the hepatic cells in foetuses with Meckel syndrome. Methods: Sections of livers from human foetuses with Meckel syndrome were analysed by immunofluorescence, immunohistochemistry and electron microscopy. Results: The primary cilia of the biliary cells were absent in some Meckel foetuses, but were present in others. In addition, defects in hepatic differentiation were observed in Meckel livers, as evidenced by the presence of hybrid cells co-expressing hepatocytic and biliary markers. Conclusions: Defects in cilia formation occur in some Meckel livers, and most cases show DPM associated with abnormal hepatic cell differentiation. Because differentiation precedes the formation of the cilia during liver development, we propose that defective differentiation may constitute the initial defect in the liver of Meckel syndrome foetuses. [ABSTRACT FROM AUTHOR]

Background: We recently showed that human hepatic progenitor cells (HPCs) express muscarinic acetylcholine (Ach) receptor subtype 3 and that – following liver transplantation – HPC numbers are significantly reduced. To further elaborate on this, we examined whether HPC also express receptors for vasoactive intestinal peptide (VIP), which, besides Ach, also is an important parasympathetic neurotransmitter. VIP expressing nerves are known to be present in the liver. Methods: We performed immunohistochemistry for VIP receptor subtypes 1 and 2 (VIPR1 and 2), on sections of normal and diseased human liver ( n=17), and double staining for VIPR2 and known HPC markers. We performed RT-PCR for VIPR1 and 2 on total RNA from purified rat HPC. To document the probability of direct interaction, we also performed double immunostaining for nerve markers and HPC markers on human liver sections. Results: VIPR2 immunostaining was clearly positive in HPC and reactive bile ductules on paraffin-embedded and frozen tissue sections. We could not demonstrate VIPR1 protein expression in the liver, with either of two VIPR1 antibodies tested. The presence of VIPR2 mRNA in HPC was confirmed by RT-PCR. Nerve endings were shown to abut on reactive bile ductules. Conclusion: We show here for the first time that HPC express VIPR2 and receive nerve endings. These features, and the fact that HPC numbers are influenced by the presence or absence of the autonomic innervation of the liver, suggest a direct interaction. [ABSTRACT FROM AUTHOR]

Libbrecht L, Desmet V, Roskams T. Preneoplastic lesions in human hepatocarcinogenesis.Liver International 2005: 25: 16–27.© Blackwell Munksgaard, 2005The early stages of hepatocarcinogenesis in human chronic liver diseases are characterized by the emergence of preneoplastic lesions of which some will eventually develop into hepatocellular carcinoma (HCC). Basic studies on the genetic and epigenetic alterations of these preneoplastic lesions may eventually lead to new therapeutic strategies. Clinicopathological studies are also important in order to determine optimal management of patients with a preneoplastic lesion. This article aims to provide a comprehensive review of the current concepts of preneoplastic lesion in chronic liver diseases. The microscopical small-cell dysplastic focus is the smallest morphologically recognizable precursor lesion of HCC and therefore is a logical target of study to elucidate the earliest events in hepatocarcinogenesis. In contrast, large-cell dysplasia is not a precursor lesion, but appears to be of clinical value because of its good predictive value for development of HCC. Dysplastic nodules (DNs) are macroscopically recognizable precursor lesions of HCC and high-grade DNs (HGDNs) have a risk of malignant transformation. Detection of DNs and correct differentiation from small HCC (<2 cm) is sometimes difficult, especially when only imaging techniques are used. Additional clinicopathological studies on identification and optimal treatment of DNs are necessary. Molecular studies on HGDNs and small HCCs may yield much information on the genetic mechanisms involved in the transition from severe dysplasia to early malignancy. In contrast, currently available data indicate that (large) regenerative nodules do not represent a distinct step in hepatocarcinogenesis. Animal models will be helpful in the further unravelling of human HCC development, provided that studies are performed on models that are good representatives of human hepatocarcinogenesis. We propose three criteria by which good mimickers can be identified. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Ductal carcinoma in situ—update on risk assessment and management," by J. M. Pang, K. L. Gorringe, and S. B. Fox in the 2016 issue.

The article discusses the role of Glypican-3 (GPC3) in solid pseudopapillary neoplasm (SPN) of the pancreas. It notes that GPC3 is a cell-surface protein that regulates the Wnt-signalling pathway and is highly expressed in hepatocellular carcinoma (HCC). It mentions that GPC3 functions as a tumour suppressor gene and an oncofetal protein in some tissues and is also expressed in various embryonal tumours. It reveals that the pancreatic SPN is associated with pancreatic development.

Presents a letter to the editor in response to the article "Stellate-Type Scirrhous Dysplastic Nodules in Liver Cirrhosis: Identical to Focal Nodular Hyperplasia-Like Nodules?,' that was previously published in the "Journal of Gastroenterology and Hepatology."

Background/Aims: The development of the intrahepatic bile ducts most likely requires interactions between epithelial and mesenchymal cells. In view of the epithelial–mesenchymal interactions between portal myofibroblasts (pMFs) and biliary epithelial cells in adult diseases of the bile ducts, we investigated the presence and function of pMFs during the development of intrahepatic bile ducts, as well as the development of intrahepatic branches of the hepatic artery. Methods: We performed haematoxylin-eosin-stainings and immunohistochemistry for alpha-smooth-muscle actin, cytokeratin 19 and vimentin on serial sections of 45 fetal and postnatal liver biopsies. Results: The mesenchyme of portal tracts in the ductal plate stage devoid of a hepatic artery branch, contained numerous and diffusely scattered pMFs. Portal tracts with a hepatic artery branch were always larger than those without and showed a decreasing number of pMFs. In the remodeling stage, all portal tracts contained a hepatic artery branch, and pMFs were restricted to the periductal mesenchyme. These periductal pMFs disappeared after full incorporation of the bile duct. Conclusion: Our findings strongly suggest interactions between pMFs and epithelial cells of the developing bile ducts. The development of the intrahepatic arterial branches always precedes the incorporation of the tubular segments of the ductal plate. [ABSTRACT FROM AUTHOR]