Contribution of immunoglobulin lambda light chain gene rearrangement analysis in the diagnosis of B-cell neoplasms.

Identification of clonal IGH, IGK and IGL gene rearrangements offers diagnostic adjunct in suspected B-cell neoplasms. However, many centres omit IGL analysis as its value is uncertain. A review of 567 cases with IGH, IGK and IGL rearrangement assessed using BIOMED-2 assays showed clonal immunoglobulin gene rearrangement in 54% of cases, of which 24% had a clonal IGL rearrangement. In two cases, the clonal rearrangement was detected exclusively by IGL analysis. This finding demonstrates the added value of IGL analysis for clonality assessment, especially in suspected B-cell neoplasms in which a clonal IGH and/or IGK rearrangement is not detected or is equivocal.

The role and contribution of clonality studies in the diagnosis of lymphoproliferative disorders.

OBJECTIVES: To explore the frequency, context and diagnostic impact of B- and T-lymphocyte clonality assay use in the assessment of possible lymphoproliferative disorders at a central haematopathology diagnostics hub. METHODS: All cases reported by haematopathologists over a sixteen-month period were identified, n = 4462, and those which had clonality studies undertaken analysed further. RESULTS: Clonality studies were requested in 9% of cases, directly contributing to a diagnosis being made in 79%. They were most frequently used to help distinguish reactive lymphoid infiltrates from low-grade B-cell lymphomas and in cases of possible T-cell lymphoma, facilitating a diagnosis being made in over 90% of these. In contrast when clonality assays were requested as a diagnostic adjunct in cases with an atypical cutaneous lymphoid infiltrate, and in occasional cases of lymphoid proliferations with Hodgkin-like cells or EBV-driven proliferations, a definitive final diagnosis was possible in less than 60% of cases. CONCLUSIONS: Clonality studies were used in 9% of cases assessed for a possible lymphoproliferative disorder and had a differing impact depending on the differential diagnoses being considered. These findings can be used to guide access to clonality assays by highlighting the likelihood of an informative result in different diagnostic settings.

Range of pathologies diagnosed using a minimally invasive capsule sponge to evaluate patients with reflux symptoms.

AIMS: Reflux symptoms are highly prevalent and non-specific; hence, in the absence of alarm symptoms, endoscopy referral decisions are challenging. This study evaluated whether a non-endoscopic Cytosponge could detect benign oesophageal pathologies and thus have future potential in triaging patients with persistent symptoms. METHODS AND RESULTS: Two complementary cohorts were recruited: (i) patients with reflux symptoms and no prior endoscopy (n = 409), and (ii) patients with reflux symptoms referred for endoscopy (n = 411). All patients were investigated using the Cytosponge and endoscopy. Significant epithelial inflammation was present in 130 (16%) Cytosponge samples, 32 of which had ulcer slough. Candida and significant inflammation was detected in a further 22 (2.3%) cases; epithelial infiltration with >15 eosinophils/high-power field reflecting possible eosinophilic oesophagitis (EOE) in five (0.6%); and viral inclusions suggestive of herpes oesophagitis in one (0.1%). No significant pathology was detected in the majority, 662 (81%), of Cytosponge samples. Cytosponge and endoscopy findings were in agreement in 574 (70%) cases, in 165 (67%) of the discordant cases one investigation showed mild inflammation while the other was negative, with an additional 22 (8.9%) differing on the extent of inflammation. Eighteen cases with severe inflammation, six with candida and two with EOE were detected only at endoscopy, while 18 with candida and significant inflammation, 13 with ulcer slough, one probable EOE and one viral oesophagitis were identified on the Cytosponge only. CONCLUSIONS: The Cytosponge detects a range of benign oesophageal pathologies, and therefore has potential clinical utility in the triaging of patients with troublesome reflux symptoms. This warrants further investigation.

Any value in a specialist review of liver biopsies? Conclusions of a 4-year review.

AIMS: Liver pathology is a challenging subspeciality, with histopathologists frequently seeking specialist opinions. This study aims to determine the impact of specialist reviews on the final diagnosis and patient management. METHODS AND RESULTS: Agreement with the initial reporting centre in the histopathological diagnosis of 1265 liver biopsies was determined. The nature of differences was explored in more depth for 103 discrepant cases. Differences in the histopathological interpretation were present in 749 of 1265 (59%) biopsies, of which 505 of 749 (67%) were predicted at the time of reporting to impact upon patient management. Agreement was good in cases with chronic viral hepatitis, fatty liver disease, malignancy and minimal pathological changes, while diagnostic differences occurred in more than 70% with biliary disease, autoimmune hepatitis or vascular/architectural changes. A clinical review of a subset of reports with histopathological differences predicted changes in patient management in 63 of 103 (61%). CONCLUSIONS: Clinically significant differences in liver biopsy interpretation between local pathologists and subspecialists are common. Diagnoses with frequent discrepancies, such as biliary disease, may benefit from a specialist review as standard when diagnosed initially, while cases requiring specialist advice from disease subgroups where discrepancies are less common, such as chronic viral hepatitis, could be selected during the clinicopathological conference process.

Mobile element insertions are frequent in oesophageal adenocarcinomas and can mislead paired-end sequencing analysis.

BACKGROUND: Mobile elements are active in the human genome, both in the germline and cancers, where they can mutate driver genes. RESULTS: While analysing whole genome paired-end sequencing of oesophageal adenocarcinomas to find genomic rearrangements, we identified three ways in which new mobile element insertions appear in the data, resembling translocation or insertion junctions: inserts where unique sequence has been transduced by an L1 (Long interspersed element 1) mobile element; novel inserts that are confidently, but often incorrectly, mapped by alignment software to L1s or polyA tracts in the reference sequence; and a combination of these two ways, where different sequences within one insert are mapped to different loci. We identified nine unique sequences that were transduced by neighbouring L1s, both L1s in the reference genome and L1s not present in the reference. Many of the resulting inserts were small fragments that include little or no recognisable mobile element sequence. We found 6 loci in the reference genome to which sequence reads from inserts were frequently mapped, probably erroneously, by alignment software: these were either L1 sequence or particularly long polyA runs. Inserts identified from such apparent rearrangement junctions averaged 16 inserts/tumour, range 0-153 insertions in 43 tumours. However, many inserts would not be detected by mapping the sequences to the reference genome, because they do not include sufficient mappable sequence. To estimate total somatic inserts we searched for polyA sequences that were not present in the matched normal or other normals from the same tumour batch, and were not associated with known polymorphisms. Samples of these candidate inserts were verified by sequencing across them or manual inspection of surrounding reads: at least 85 % were somatic and resembled L1-mediated events, most including L1Hs sequence. Approximately 100 such inserts were detected per tumour on average (range zero to approximately 700). CONCLUSIONS: Somatic mobile elements insertions are abundant in these tumours, with over 75 % of cases having a number of novel inserts detected. The inserts create a variety of problems for the interpretation of paired-end sequencing data.

Characterization of the timing and prevalence of receptor tyrosine kinase expression changes in oesophageal carcinogenesis.

Despite being common in epithelial malignancies, the timing of receptor tyrosine kinase (RTK) up-regulation is poorly understood and therefore hampers the identification of the receptor to target for effective treatment. We aimed to determine if RTK expression changes were early events in carcinogenesis. Oesophageal adenocarcinoma and its pre-invasive lesion, Barrett's oesophagus, were used for immunohistochemical analysis of the RTK panel, EGFR, ErbB2, ErbB3, Met, and FGFR2, by utilizing a cohort of patients with invasive disease (n = 367) and two cohorts with pre-invasive disease, one cross-sectional (n = 110) and one longitudinal in time (n = 91). The results demonstrated that 51% of oesophageal adenocarcinomas overexpressed at least one of the RTK panel, with 21% of these overexpressing multiple receptors. Up-regulation of RTK expression was an early event corresponding with low-grade dysplasia development (25% in areas without dysplasia versus 63% in low-grade dysplasia, p < 0.001). There was a trend for an increase in the prevalence of concomitant overexpression of multiple receptors as intestinal metaplasia progressed to low-grade dysplasia, 7% versus 10%; and from low-grade dysplasia to high-grade dysplasia, 10% versus 19% (p = 0.06 and 0.24, respectively). The timing of receptor up-regulation varied; FGFR, ErbB2, and Met overexpression occurred as dysplasia first developed, whilst EGFR overexpression was predominately seen in invasive disease and ErbB3 overexpression was uniformly rare. We provide evidence for a frequent and early role for multiple different RTKs in oesophageal carcinogenesis. Given the early timing of receptor deregulation, inhibiting RTKs in pre-invasive disease may also represent a novel and effective chemopreventive strategy.

A systematic approach to therapeutic target selection in oesophago-gastric cancer.

OBJECTIVE: The success of personalised therapy depends on identification and inhibition of the oncogene(s) on which that tumour is dependent. We aimed to determine whether a receptor tyrosine kinase (RTK) array could be used to select the most effective therapeutic strategies in molecularly heterogeneous oesophago-gastric adenocarcinomas. DESIGN: Gene expression profiling from oesophago-gastric tumours (n=75) and preinvasive stages (n=57) identified the active signalling pathways, which was confirmed using immunohistochemistry (n=434). RTK arrays on a cell line panel (n=14) determined therapeutic targets for in vitro cytotoxic testing. Feasibility of this personalised approach was tested in tumour samples (n=46). RESULTS: MAPK was the most frequently activated pathway (32/75 samples (42.7%)) with progressive enrichment in preinvasive disease stages (p<0.05) and ERK phosphorylation in 148/434 (34.3%) independent samples. Cell lines displayed a range of RTK activation profiles. When no RTKs were activated, tyrosine kinase inhibitors (TKIs) and a Mek inhibitor were not useful (MKN1). In lines with a dominant phosphorylated RTK (OE19, MKN45 and KATOIII), selection of this TKI or Mek in nM concentrations induced cytotoxicity and inhibited Erk and Akt phosphorylation. In cells lines with complex activation profiles (HSC39 and OE33), a combination of TKIs or Mek inhibition (in nM concentrations) was necessary for cytotoxicity and inhibition of Erk and Akt phosphorylation. Human tumours demonstrated diverse activation profiles and 65% of cases had two or more active RTKs. CONCLUSIONS: The MAPK pathway is commonly activated in oesophago-gastric cancer following activation of a variety of RTKs. Molecular phenotyping can inform a rational choice of targeted therapy.

Expression of the apelin receptor, a novel potential therapeutic target, and its endogenous ligands in diverse stem cell populations in human glioblastoma.

Glioblastoma multiforme (GBM) is one of the most common and lethal forms of brain cancer, carrying a very poor prognosis (median survival of ~15 months post-diagnosis). Treatment typically involves invasive surgical resection of the tumour mass, followed by radiotherapy and adjuvant chemotherapy using the alkylating agent temozolomide, but over half of patients do not respond to this drug and considerable resistance is observed. Tumour heterogeneity is the main cause of therapeutic failure, where diverse progenitor glioblastoma stem cell (GSC) lineages in the microenvironment drive tumour recurrence and therapeutic resistance. The apelin receptor is a class A GPCR that binds two endogenous peptide ligands, apelin and ELA, and plays a role in the proliferation and survival of cancer cells. Here, we used quantitative whole slide immunofluorescent imaging of human GBM samples to characterise expression of the apelin receptor and both its ligands in the distinct GSC lineages, namely neural-progenitor-like cells (NPCs), oligodendrocyte-progenitor-like cells (OPCs), and mesenchymal-like cells (MES), as well as reactive astrocytic cells. The data confirm the presence of the apelin receptor as a tractable drug target that is common across the key cell populations driving tumour growth and maintenance, offering a potential novel therapeutic approach for patients with GBM.

Co-localization of the sodium-glucose co-transporter-2 channel (SGLT-2) with endothelin ETA and ETB receptors in human cardiorenal tissue.

Endothelin (ET) receptor antagonists are being investigated in combination with sodium-glucose co-transporter-2 inhibitors (SGLT-2i). These drugs primarily inhibit the SGLT-2 transporter that, in humans, is thought to be mainly restricted to the renal proximal convoluted tubule, resulting in increased glucose excretion favouring improved glycaemic control and diuresis. This action reduces fluid retention with ET receptor antagonists. Studies have suggested SGLT-2 may also be expressed in cardiomyocytes of human heart. To understand the potential of combining the two classes of drugs, our aim was to compare the distribution of ET receptor sub-types in human kidney, with SGLT-2. Secondly, using the same experimental conditions, we determined if SGLT-2 expression could be detected in human heart and whether the transporter co-localised with ET receptors. METHODS: Immunocytochemistry localised SGLT-2, ETA and ETB receptors in sections of histologically normal kidney, left ventricle from patients undergoing heart transplantation or controls. Primary antisera were visualised using fluorescent microscopy. Image analysis was used to measure intensity compared with background in adjacent control sections. RESULTS: As expected, SGLT-2 localised to epithelial cells of the proximal convoluted tubules, and co-localised with both ET receptor sub-types. Similarly, ETA receptors predominated in cardiomyocytes; low (compared with kidney but above background) positive staining was also detected for SGLT-2. DISCUSSION: Whether low levels of SGLT-2 have a (patho)physiological role in cardiomyocytes is not known but results suggest the effect of direct blockade of sodium (and glucose) influx via SGLT-2 inhibition in cardiomyocytes should be explored, with potential for additive effects with ETA antagonists.

Differential expression in humans of the viral entry receptor ACE2 compared with the short deltaACE2 isoform lacking SARS-CoV-2 binding sites.

ACE2 is a membrane protein that regulates the cardiovascular system. Additionally, ACE2 acts as a receptor for host cell infection by human coronaviruses, including SARS-CoV-2 that emerged as the cause of the on-going COVID-19 pandemic and has brought unprecedented burden to economy and health. ACE2 binds the spike protein of SARS-CoV-2 with high affinity and shows little variation in amino acid sequence meaning natural resistance is rare. The discovery of a novel short ACE2 isoform (deltaACE2) provides evidence for inter-individual differences in SARS-CoV-2 susceptibility and severity, and likelihood of developing subsequent 'Long COVID'. Critically, deltaACE2 loses SARS-CoV-2 spike protein binding sites in the extracellular domain, and is predicted to confer reduced susceptibility to viral infection. We aimed to assess the differential expression of full-length ACE2 versus deltaACE2 in a panel of human tissues (kidney, heart, lung, and liver) that are implicated in COVID-19, and confirm ACE2 protein in these tissues. Using dual antibody staining, we show that deltaACE2 localises, and is enriched, in lung airway epithelia and bile duct epithelia in the liver. Finally, we also confirm that a fluorescently tagged SARS-CoV-2 spike protein monomer shows low binding at lung and bile duct epithelia where dACE2 is enriched.

Role of TFF3 as an adjunct in the diagnosis of Barrett's esophagus using a minimally invasive esophageal sampling device-The CytospongeTM.

The incidence of esophageal carcinoma continues to increase whilst its prognosis remains poor. The most dramatic reduction in mortality is likely to follow early diagnosis of the preinvasive precursor lesion, Barrett's esophagus (BE), coupled with treatment of dysplastic lesions. The major risk factor for BE is gastroesophageal reflux disease, however this is highly prevalent and only a small proportion of individuals have BE, therefore an endoscopy-based screening strategy to detect BE is unfeasible. Minimally invasive esophageal sampling devices offer an alternative, cost-effective strategy which can be deployed within an at-risk population in a primary care setting to identify individuals with probable BE who can then be referred for endoscopic confirmation. The device that has currently progressed furthest in clinical trials is the CytospongeTM which collects cells from the gastric cardia, gastroesophageal junction and along the whole esophageal length. The cell sample is processed into a formalin-fixed paraffin-embedded block and sections assessed for the presence of intestinal metaplasia. TFF3 immunohistochemistry has consistently been shown to be a valuable adjunct that increases the accuracy of the CytospongeTM test by highlighting early goblet cells which may be missed on morphological assessment and by allowing pseudogoblet cells to be differentiated from true goblet cells.

PIK3R1W624R Is an Actionable Mutation in High Grade Serous Ovarian Carcinoma.

Identifying cancer drivers and actionable mutations is critical for precision oncology. In epithelial ovarian cancer (EOC) the majority of mutations lack biological or clinical validation. We fully characterized 43 lines of Patient-Derived Xenografts (PDXs) and performed copy number analysis and whole exome sequencing of 12 lines derived from naïve, high grade EOCs. Pyrosequencing allowed quantifying mutations in the source tumours. Drug response was assayed on PDX Derived Tumour Cells (PDTCs) and in vivo on PDXs. We identified a PIK3R1W624R variant in PDXs from a high grade serous EOC. Allele frequencies of PIK3R1W624R in all the passaged PDXs and in samples of the source tumour suggested that it was truncal and thus possibly a driver mutation. After inconclusive results in silico analyses, PDTCs and PDXs allowed the showing actionability of PIK3R1W624R and addiction of PIK3R1W624R carrying cells to inhibitors of the PI3K/AKT/mTOR pathway. It is noteworthy that PIK3R1 encodes the p85α regulatory subunit of PI3K, that is very rarely mutated in EOC. The PIK3R1W624R mutation is located in the cSH2 domain of the p85α that has never been involved in oncogenesis. These data show that patient-derived models are irreplaceable in their role of unveiling unpredicted driver and actionable variants in advanced ovarian cancer.

Biomarkers in Barrett's oesophagus and oesophageal adenocarcinoma.

Barrett's oesophagus is a well-recognised premalignant lesion for oesophageal adenocarcinoma. It is present in 1 - 2% of the general population, and 2 - 5% of those with gastro-oesophageal reflux disease. The majority of Barrett's cases within the population are undiagnosed, consequently most cases of oesophageal adenocarcinoma arise de novo. The incidence of oesophageal adenocarcinoma has increased by more than sixfold in the last 30 years. However, most patients with Barrett's oesophagus will not develop oesophageal adenocarcinoma. The major focus of biomarker research in Barrett's oesophagus is to find a marker that is able to identify patients at the highest risk of progressing to adenocarcinoma. Other potential roles include increasing the sensitivity of minimally invasive screening tests to identify patients with Barrett's oesophagus and predicting which patients are most likely to benefit from chemoprevention and endoscopic therapies. In established oesophageal adenocarcinoma, biomarkers would be able to individualise patient management by providing valuable information on patient prognosis and their suitability for novel targeted therapies. This review aims to explore the potential roles of biomarkers in Barrett's oesophagus and oesophageal adenocarcinoma, focusing on the most extensively studied candidates and future novel developments.

Co-amplification of 8p12 and 11q13 in breast cancers is not the result of a single genomic event.

Epithelial cancers frequently have multiple amplifications, and particular amplicons tend to occur together. These co-amplifications have been suggested to result from amplification of pre-existing junctions between two chromosomes, that is, translocation junctions. We investigated this hypothesis for two amplifications frequent in breast cancer, at 8p12 and 11q13, which had been reported to be associated in Southern blot studies. We confirmed that both genomic amplification and expression of genes was correlated between the frequently-amplified regions of 8p and 11q, in array CGH and microarray expression data, supporting the importance of co-amplification. We examined by FISH the physical structure of co-amplifications that we had identified by array CGH, in five breast cancer cell lines (HCC1500, MDA-MB-134, MDA-MB-175, SUM44, and ZR-75-1), four breast tumors, and a pancreatic cancer cell line (SUIT2). We found a variety of arrangements: amplification of translocation junctions; entirely independent amplification of the two regions on separate chromosomes; and separate amplification of 8p and 11q sequences in distinct sites on the same rearranged chromosome. In this last arrangement, interphase nuclei often showed intermingling of FISH signals from 8p12 and 11q13, giving a false impression that the sequences were interdigitated. We conclude that co-amplification of the main 8p and 11q amplicons in breast tumors is not usually the result of a preceding translocation event but most likely reflects selection of clones that have amplified both loci. This article contains supplementary material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.