An atypical presentation of gastrointestinal stromal tumour: a case report

Gastrointestinal stromal tumours (GIST) occur more commonly in the stomach and make up ~80% of the GI mesenchymal neoplasms. They are very rare in young adults and in males. The diagnosis is confirmed histologically and immunohistochemically. Once diagnosed, survival rates are dependent on various factors. The main treatment is resection, but targeted therapy can be used pre or post-operatively. This case is of a 35-year-old female with no significant medical history presenting to her general practitioner with lethargy, malaise and mild weight loss. Initially, she was investigated for a haematological malignancy, but upon further investigations, her computed tomography (CT)  scan showed an abdominal mass, which was resected and found to be a high-grade perforated gastrointestinal stromal tumour in her proximal ileum. This is a good example of an atypical presentation of GIST and emphasizes the importance of thorough workup and prompt surgical intervention in achieving a satisfactory outcome.

The tale of TILs in breast cancer: A report from The International Immuno-Oncology Biomarker Working Group

The advent of immune-checkpoint inhibitors (ICI) in modern oncology has significantly improved survival in several cancer settings. A subgroup of women with breast cancer (BC) has immunogenic infiltration of lymphocytes with expression of programmed death-ligand 1 (PD-L1). These patients may potentially benefit from ICI targeting the programmed death 1 (PD-1)/PD-L1 signaling axis. The use of tumor-infiltrating lymphocytes (TILs) as predictive and prognostic biomarkers has been under intense examination. Emerging data suggest that TILs are associated with response to both cytotoxic treatments and immunotherapy, particularly for patients with triple-negative BC. In this review from The International Immuno-Oncology Biomarker Working Group, we discuss (a) the biological understanding of TILs, (b) their analytical and clinical validity and efforts toward the clinical utility in BC, and (c) the current status of PD-L1 and TIL testing across different continents, including experiences from low-to-middle-income countries, incorporating also the view of a patient advocate. This information will help set the stage for future approaches to optimize the understanding and clinical utilization of TIL analysis in patients with BC.

Fatal acute hepatic failure secondary to thrombotic portal venopathy after commencing abemaciclib and fulvestrant treatment for advanced breast carcinoma: a unique autopsy finding

We present an autopsy case of hepatic thrombotic portal venopathy resulting in decompensated liver failure and death which occurred rapidly after commencing abemaciclib and fulvestrant chemotherapy for advanced invasive lobular carcinoma of the breast. The diagnosis was confirmed histologically. This is the first reported case of such a finding. We suggest that further cases displaying this previously unpublished pattern are collated in order that we may begin to investigate the underlying etiological mediators.

The path to a better biomarker: application of a risk management framework for the implementation of PD-L1 and TILs as immuno-oncology biomarkers in breast cancer clinical trials and daily practice

Immune checkpoint inhibitor therapies targeting PD-1/PD-L1 are now the standard of care in oncology across several hematologic and solid tumor types, including triple negative breast cancer (TNBC). Patients with metastatic or locally advanced TNBC with PD-L1 expression on immune cells occupying ≥1% of tumor area demonstrated survival benefit with the addition of atezolizumab to nab-paclitaxel. However, concerns regarding variability between immunohistochemical PD-L1 assay performance and inter-reader reproducibility have been raised. High tumor-infiltrating lymphocytes (TILs) have also been associated with response to PD-1/PD-L1 inhibitors in patients with breast cancer (BC). TILs can be easily assessed on hematoxylin and eosin-stained slides and have shown reliable inter-reader reproducibility. As an established prognostic factor in early stage TNBC, TILs are soon anticipated to be reported in daily practice in many pathology laboratories worldwide. Because TILs and PD-L1 are parts of an immunological spectrum in BC, we propose the systematic implementation of combined PD-L1 and TIL analyses as a more comprehensive immuno-oncological biomarker for patient selection for PD-1/PD-L1 inhibition-based therapy in patients with BC. Although practical and regulatory considerations differ by jurisdiction, the pathology community has the responsibility to patients to implement assays that lead to optimal patient selection. We propose herewith a risk-management framework that may help mitigate the risks of suboptimal patient selection for immuno-therapeutic approaches in clinical trials and daily practice based on combined TILs/PD-L1 assessment in BC. © 2020 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Synchronous small lymphocytic lymphoma and metastatic breast carcinoma in axillary lymph nodes: Preservation of follicular architecture only in the portions of affected lymph nodes involved by metastatic carcinoma

We present a case of metastatic ductal carcinoma of breast with the incidental discovery of small lymphocytic lymphoma (SLL) in regional axillary nodes. The co-occurence of metastatic carcinoma and low-grade lymphoma in lymph nodes is rare but well recognized. However, in this case, in the lymph nodes in which sizeable metastatic carcinoma deposits were present, the follicular structures between the sinusoidal carcinomatous infiltrates were preserved, whereas the uninvolved portions of the nodes were overrun by SLL. This is the first description of this phenomenon. We suggest that further cases displaying this previously unpublished pattern are collated in order that we may begin to investigate the underlying etiological mediators.

shRNA-mediated PPARα knockdown in human glioma stem cells reduces in vitro proliferation and inhibits orthotopic xenograft tumour growth

The overall survival for patients with primary glioblastoma is very poor. Glioblastoma contains a subpopulation of glioma stem cells (GSC) that are responsible for tumour initiation, treatment resistance and recurrence. PPARα is a transcription factor involved in the control of lipid, carbohydrate and amino acid metabolism. We have recently shown that PPARα gene and protein expression is increased in glioblastoma and has independent clinical prognostic significance in multivariate analyses. In this work, we report that PPARα is overexpressed in GSC compared to foetal neural stem cells. To investigate the role of PPARα in GSC, we knocked down its expression using lentiviral transduction with short hairpin RNA (shRNA). Transduced GSC were tagged with luciferase and stereotactically xenografted into the striatum of NOD-SCID mice. Bioluminescent and magnetic resonance imaging showed that knockdown (KD) of PPARα reduced the tumourigenicity of GSC in vivo. PPARα-expressing control GSC xenografts formed invasive histological phenocopies of human glioblastoma, whereas PPARα KD GSC xenografts failed to establish viable intracranial tumours. PPARα KD GSC showed significantly reduced proliferative capacity and clonogenic potential in vitro with an increase in cellular senescence. In addition, PPARα KD resulted in significant downregulation of the stem cell factors c-Myc, nestin and SOX2. This was accompanied by downregulation of the PPARα-target genes and key regulators of fatty acid oxygenation ACOX1 and CPT1A, with no compensatory increase in glycolytic flux. These data establish the aberrant overexpression of PPARα in GSC and demonstrate that this expression functions as an important regulator of tumourigenesis, linking self-renewal and the malignant phenotype in this aggressive cancer stem cell subpopulation. We conclude that targeting GSC PPARα expression may be a therapeutically beneficial strategy with translational potential as an adjuvant treatment. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Bone marrow transplantation stimulates neural repair in Friedreich's ataxia mice

OBJECTIVE

Friedreich's ataxia is an incurable inherited neurological disease caused by frataxin deficiency. Here, we report the neuroreparative effects of myeloablative allogeneic bone marrow transplantation in a humanized murine model of the disease.

METHODS

Mice received a transplant of fluorescently tagged sex-mismatched bone marrow cells expressing wild-type frataxin and were assessed at monthly intervals using a range of behavioral motor performance tests. At 6 months post-transplant, mice were euthanized for protein and histological analysis. In an attempt to augment numbers of bone marrow-derived cells integrating within the nervous system and improve therapeutic efficacy, a subgroup of transplanted mice also received monthly subcutaneous infusions of the cytokines granulocyte-colony stimulating factor and stem cell factor.

RESULTS

Transplantation caused improvements in several indicators of motor coordination and locomotor activity. Elevations in frataxin levels and antioxidant defenses were detected. Abrogation of disease pathology throughout the nervous system was apparent, together with extensive integration of bone marrow-derived cells in areas of nervous tissue injury that contributed genetic material to mature neurons, satellite-like cells, and myelinating Schwann cells by processes including cell fusion. Elevations in circulating bone marrow-derived cell numbers were detected after cytokine administration and were associated with increased frequencies of Purkinje cell fusion and bone marrow-derived dorsal root ganglion satellite-like cells. Further improvements in motor coordination and activity were evident.

INTERPRETATION

Our data provide proof of concept of gene replacement therapy, via allogeneic bone marrow transplantation, that reverses neurological features of Friedreich's ataxia with the potential for rapid clinical translation. Ann Neurol 2018;83:779-793.

Evaluation of the quality of RNA extracted from archival FFPE glioblastoma and epilepsy surgical samples for gene expression assays

Aims

Histopathological tissue samples are being increasingly used as sources of nucleic acids in molecular pathology translational research. This study investigated the suitability of glioblastoma and control central nervous system (CNS) formalin-fixed paraffin embedded (FFPE) tissue-derived RNA for gene expression analyses.

Methods

Total RNA was extracted from control (temporal lobe resection tissue) and glioblastoma FFPE tissue samples. RNA purity (260/280 ratios) was determined and RNA integrity number (RIN) analysis was performed. RNA was subsequently used for RT-qPCR for two reference genes,18SandGAPDH.

Results

Reference gene expression was equivalent between control and glioblastoma tissue when using RNA extracted from FFPE tissue, which has key implications for biological normalisation for CNS gene expression studies. There was a significant difference between the mean RIN values of control and glioblastoma FFPE tissue. There was no significant correlation between 260/280 or RIN values versus total RNA yield. The age of the tissue blocks did not influence RNA yield, fragmentation or purity. There was no significant correlation between RIN or 260/280 ratios and mean qPCR cycle threshold for either reference gene.

Conclusions

This study showed that routinely available CNS FFPE tissue is suitable for RNA extraction and downstream gene expression studies, even after 60 months of storage. Substantial RNA fragmentation associated with glioblastoma and control FFPE tissue blocks did not preclude downstream RT-qPCR gene expression analyses. Cross validation with both archival and prospectively collated FFPE specimens is required to further demonstrate that CNS tissue blocks can be used in novel translational molecular biomarker studies.

HER2 testing of gastro-oesophageal adenocarcinoma: a commentary and guidance document from the Association of Clinical Pathologists Molecular Pathology and Diagnostics Committee

The use of biologics targeted to the human epidermal growth factor receptor 2 (HER2) protein is the latest addition to the armamentarium used to fight advanced gastric or gastro-oesophageal junction adenocarcinoma. The decision to treat with the biologic trastuzumab is completely dependent on HER2 testing of tumour tissue. In 2017, the College of American Pathologists, American Society for Clinical Pathology and the American Society of Clinical Oncology jointly published guidelines for HER2 testing and clinical decision making in gastro-oesophageal adenocarcinoma. The Association of Clinical Pathologists Molecular Pathology and Diagnostics Committee has issued the following document as a commentary of these guidelines and, in parallel, to provide guidance on HER2 testing in National Health Service pathology departments within the UK. This guidance covers issues related to case selection, preanalytical aspects, analysis and interpretation of such HER2 testing.

A case of chronic asymptomatic central pontine myelinolysis with histological evidence of remyelination

Central pontine myelinolysis (CPM) is a neurological demyelinating disease of the pons. Although usually associated with rapid correction of hyponatremia, CPM may occur despite normonatremia, is often associated with chronic alcoholism and may be asymptomatic. Histological confirmation of asymptomatic CPM is rare. We describe an unusual post-mortem case of extensive but asymptomatic CPM in a chronic alcoholic patient with normonatremia. The affected part of the pons contained thinly myelinated axons with appearances supporting remyelination. We suggest that remyelination may account for the subclinical nature of this patient's CPM.

The transcription factor PPARα is overexpressed and is associated with a favourable prognosis in IDH-wildtype primary glioblastoma

AIMS

PPARα agonists are in current clinical use as hypolipidaemic agents and show significant antineoplastic effects in human glioblastoma models. To date however, the expression of PPARα in large-scale glioblastoma datasets has not been examined. We aimed to investigate the expression of the transcription factor PPARα in primary glioblastoma, the relationship between PPARα expression and patients' clinicopathological features and other molecular markers associated with gliomagenesis.

METHODS AND RESULTS

With protein immunoblotting techniques and reverse transcription quantitative real-time PCR, PPARα was found to be significantly overexpressed in glioblastoma compared with control brain tissue (P = 0.032 and P = 0.005). PPARA gene expression was found to be enriched in the classical glioblastoma subtype within The Cancer Genome Atlas (TCGA) dataset. Although not associated with overall survival when assessed by immunohistochemistry, cross-validation with the TCGA dataset and multivariate analyses identified PPARA gene expression as an independent prognostic marker for overall survival (P = 0.042). Finally, hierarchical clustering revealed novel, significant associations between high PPARA expression and a putative set of glioblastoma molecular mediators including EMX2, AQP4, and NTRK2.

CONCLUSIONS

PPARα is overexpressed in primary glioblastoma and high PPARA expression functions as an independent prognostic marker in the glioblastoma TCGA dataset. Further studies are required to explore genetic associations with high PPARA expression and to analyse the predictive role of PPARα expression in glioblastoma models in response to PPARα agonists.

Convection enhanced delivery of panobinostat (LBH589)-loaded pluronic nano-micelles prolongs survival in the F98 rat glioma model

Background

The pan-histone deacetylase inhibitor panobinostat is a potential therapy for malignant glioma, but it is water insoluble and does not cross the blood–brain barrier when administered systemically. In this article, we describe the in vitro and in vivo efficacy of a novel water-soluble nano-micellar formulation of panobinostat designed for administration by convection enhanced delivery (CED).

Materials and methods

The in vitro efficacy of panobinostat-loaded nano-micelles against rat F98, human U87-MG and M059K glioma cells and against patient-derived glioma stem cells was measured using a cell viability assay. Nano-micelle distribution in rat brain was analyzed following acute CED using rhodamine-labeled nano-micelles, and toxicity was assayed using immunofluorescent microscopy and synaptophysin enzyme-linked immunosorbent assay. We compared the survival of the bioluminescent syngenic F98/Fischer344 rat glioblastoma model treated by acute CED of panobinostat-loaded nano-micelles with that of untreated and vehicle-only-treated controls.

Results

Nano-micellar panobinostat is cytotoxic to rat and human glioma cells in vitro in a dose-dependent manner following short-time exposure to drug. Fluorescent rhodamine-labelled nano-micelles distribute with a volume of infusion/volume of distribution (Vi/Vd) ratio of four and five respectively after administration by CED. Administration was not associated with any toxicity when compared to controls. CED of panobinostat-loaded nano-micelles was associated with significantly improved survival when compared to controls (n=8 per group; log-rank test, P<0.001). One hundred percent of treated animals survived the 60-day experimental period and had tumour response on post-mortem histological examination.

Conclusion

CED of nano-micellar panobinostat represents a potential novel therapeutic option for malignant glioma and warrants translation into the clinic.

Cytokine therapy-mediated neuroprotection in a Friedreich's ataxia mouse model

OBJECTIVES

Friedreich's ataxia is a devastating neurological disease currently lacking any proven treatment. We studied the neuroprotective effects of the cytokines, granulocyte-colony stimulating factor (G-CSF) and stem cell factor (SCF) in a humanized murine model of Friedreich's ataxia.

METHODS

Mice received monthly subcutaneous infusions of cytokines while also being assessed at monthly time points using an extensive range of behavioral motor performance tests. After 6 months of treatment, neurophysiological evaluation of both sensory and motor nerve conduction was performed. Subsequently, mice were sacrificed for messenger RNA, protein, and histological analysis of the dorsal root ganglia, spinal cord, and cerebellum.

RESULTS

Cytokine administration resulted in significant reversal of biochemical, neuropathological, neurophysiological, and behavioural deficits associated with Friedreich's ataxia. Both G-CSF and SCF had pronounced effects on frataxin levels (the primary molecular defect in the pathogenesis of the disease) and a regulators of frataxin expression. Sustained improvements in motor coordination and locomotor activity were observed, even after onset of neurological symptoms. Treatment also restored the duration of sensory nerve compound potentials. Improvements in peripheral nerve conduction positively correlated with cytokine-induced increases in frataxin expression, providing a link between increases in frataxin and neurophysiological function. Abrogation of disease-related pathology was also evident, with reductions in inflammation/gliosis and increased neural stem cell numbers in areas of tissue injury.

INTERPRETATION

These experiments show that cytokines already clinically used in other conditions offer the prospect of a novel, rapidly translatable, disease-modifying, and neuroprotective treatment for Friedreich's ataxia. Ann Neurol 2017;81:212-226.

Sudden unexpected death from an undiagnosed histiocytic sarcoma in an adolescent female

A previously well 15-year-old female who was awaiting medical investigations for a proptosed right eye collapsed and died suddenly while walking. Postmortem examination revealed diffuse distortion and infiltration of multiple organs by a suspected neoplastic process. Histology confirmed the invasion of multiple organs by atypical cells and myocardial infiltration was the likely cause of death. An extensive panel of immunohistochemistry established the diagnosis of a histiocytic sarcoma. Sudden unexpected death due to a clinically undiagnosed neoplasia in childhood and adolescence is uncommon. This is the first report of a histiocytic sarcoma causing sudden unexpected death and highlights the importance of considering undiagnosed hematological malignancies when examining a case of sudden death at postmortem.

Current Understanding of Circulating Tumor Cells - Potential Value in Malignancies of the Central Nervous System

Detection of circulating tumor cells (CTCs) in the blood via so-called "liquid biopsies" carries enormous clinical potential in malignancies of the central nervous system (CNS) because of the potential to follow disease evolution with a blood test, without the need for repeat neurosurgical procedures with their inherent risk of patient morbidity. To date, studies in non-CNS malignancies, particularly in breast cancer, show increasing reproducibility of detection methods for these rare tumor cells in the circulation. However, no method has yet received full recommendation to use in clinical practice, in part because of lack of a sufficient evidence base regarding clinical utility. In CNS malignancies, one of the main challenges is finding a suitable biomarker for identification of these cells, because automated systems, such as the widely used Cell Search system, are reliant on markers, such as the epithelial cell adhesion molecule, which are not present in CNS tumors. This review examines methods for CTC enrichment and detection, and reviews the progress in non-CNS tumors and the potential for using this technique in human brain tumors.

EGFR and EGFRvIII analysis in glioblastoma as therapeutic biomarkers

INTRODUCTION

EGFR and EGFRvIII analysis is of current interest because of new EGFRvIII vaccine trials opened in the UK. EGFR activation promotes cellular proliferation via activation of MAPK and PI3K-Akt pathways. EGFRvIII is the most common variant resulting from an in-frame deletion of 801bp, leading to constitutively active EGFR.

METHOD

51 glioblastoma samples from a cohort of 50 patients were tested for EGFR amplification by FISH and immunohistochemistry and EGFRvIII expression by reverse-transcriptase PCR (RT-PCR), and immunohistochemistry. EGFR and EGFRvIII expression was compared with Overall Survival in the cohort.

RESULTS

Overall 22/51 samples (43%) were positive for EGFR, 16/51 (31%) were positive for EGFRvIII and 13/51 (25%) were positive for both. 9/51 cases (18%) were positive for EGFR alone, and 3/51 (6%) were positive for EGFRvIII alone. Of the EGFR positive cases, 22/51 (43%) were positive by FISH, 24/51 (47%) were positive by IHC and 2/51 (4%) were discrepant between methods (positive by IHC but non-amplified by FISH). Of the EGFRvIII positive cases, 16/51 (31%) were positive by RT-PCR, 17/51 (33%) were positive by IHC and 1/51 (2%) sample was discrepant (positive by IHC but not by RT-PCR). Neither EGFRvIII or EGFR are predictive of overall survival in this cohort.

CONCLUSION

In our cohort, 25/51 (49%) of GBM showed EGFR alterations, including 16/51 (31%) with EGFRvIII. There was high concordance between IHC and FISH (96%) and IHC and RT-PCR (98%) as diagnostic methods. Neither EGFR or EGFRvIII is predictive of overall survival in this cohort. These results are key for selecting patients for novel individualised anti-EGFR therapies.

Prognostic and predictive biomarkers in adult and pediatric gliomas: toward personalized treatment

It is increasingly clear that both adult and pediatric glial tumor entities represent collections of neoplastic lesions, each with individual pathological molecular events and treatment responses. In this review, we discuss the current prognostic biomarkers validated for clinical use or with future clinical validity for gliomas. Accurate prognostication is crucial for managing patients as treatments may be associated with high morbidity and the benefits of high risk interventions must be judged by the treating clinicians. We also review biomarkers with predictive validity, which may become clinically relevant with the development of targeted therapies for adult and pediatric gliomas.

Thrombus formation in a dilated torcula following aneurysmal subarachnoid haemorrhage

A case of thrombus formation occurring within a dilation of the dural venous sinuses following aneurysmal sub-arachnoid haemorrhage is presented. Acute neurological deterioration accompanied propagation of the thrombus. The patient was anticoagulated on day 5 post-SAH with no haemorrhagic complications and made a full recovery. The optimum time to commence anticoagulation is not clear and is discussed.

IDH mutation analysis in gliomas as a diagnostic and prognostic biomarker

INTRODUCTION

There is a high rate of IDH1/2 mutations in low grade gliomas and in high grade gliomas deriving from them. IDH analysis of gliomas is a novel method of classification and an independent prognostic marker. We compared antibody and sequencing methods for the detection of IDH mutations.

METHOD

88 samples from 74 patients were identified. For immunohistochemistry: sections were stained with anti-IDH1R132H antibody. For sequencing: DNA was extracted from fresh, frozen tissue.

RESULTS

28% (20/71) of cases were positive for the R132H IDH1 mutation by antibody. An IDH1 mutation was detected by molecular genetics in 37% (21/57) of cases and no IDH2 mutations were detected. 24% (5/21) had rare IDH1 mutations not detected by immunohistochemistry. Where sufficient tissue was available, immunohistochemistry and DNA analysis were fully concordant for the p.Arg132His mutation. Both Grade II gliomas and anaplastic astrocytomas showed a statistically different distribution of IDH1 mutation load compared to GBMs (p < 0.0001; p = 0.0021 respectively).

CONCLUSION

A rationalised combined approach involving R132H antibody testing and sequencing of negative cases would be ideal for the detection of IDH1 mutations--antibody testing is cheaper than sequencing but sequencing demonstrates rare IDH1 mutations not detected by immunohistochemistry.