Epithelial differentiation with microlumen formation in meningioma: diagnostic utility of NHERF1/EBP50 immunohistochemistry

NHERF1/EBP50 immunoexpression in renal cell carcinomas and oncocytomas with ultrastructural analysis of clear cell renal cell carcinoma

Background

Na+/H+ exchanger (NHE) maintains the alkaline pH of epithelial cells working at the cellular membrane and exchanging H+/Na+ ions. In renal tubular epithelial cells, the reabsorption of NaCl is implemented by NHE3 isoform, which is regulated by NHE regulatory factor-1 (NHERF1). Normally situated at the apical zones of proximal tubular cells, NHERF1 participates in cytoskeletal reorganization and signal transduction facilitating structural stability and ion exchange. Based on an extensive search in English literature, NHERF1/EBP50 immunoexpression has been studied in breast, colon, and other tumors with only one study on 21 cases of renal cell carcinomas (RCC).

Methods

Using NHERF1/EBP50 immunohistochemistry (IHC) on 64 (82%) RCCs (34 clear cells, 21 papillary and 9 chromophobe types) and 14 (18%) oncocytomas, we evaluated and scored NHERF1/EBP50 immunoexpression depending on the World Health Organization (WHO)/International Society of Urological Pathology (ISUP) grading system followed by ultrastructural identification of microlumen-like structures (MLS) in clear cell renal cell carcinomas (ccRCC).

Results

Staining patterns varied throughout the tumors and within individual tumors. Only ccRCC showed unique MLS within the cytoplasm of tumor cells. All neoplasia-transformed tubular cells, regardless of the tumor grade and stage, had altered immunoexpression of NHERF1/EBP50 ranging from complete absence to aberrant expression in the luminal cell membrane, nuclear or cytoplasmic localizations.

Conclusions

Only ccRCC showed unique dot-like condensations of immunostaining/MLS at membranous, submembranous, and paranuclear localizations. The latter two localizations were mainly observed in the combined WHO/ISUP grade 1 and 2 group compared to the combined group of grade 3 and 4 tumor samples (P=0.0146 and P<0.0001, respectively). Ultrastructurally, the MLS were identified as thick microvilli trapped by a single-layer membrane, displaced into the cytoplasm and ranging from 400 nm to 3.5 µm. These significant ultrastructural reorganizations may contribute to tumor progression, metastasis, and drug resistance.

Novel neoplasms associated with syndromic pediatric medulloblastoma: integrated pathway delineation for personalized therapy

Medulloblastoma is the most common pediatric embryonal brain tumor, and may occur in cancer predisposition syndromes. We describe novel associations of medulloblastoma with atypical prolactinoma and dural high-grade sarcoma in Li-Fraumeni syndrome (LFS), and epidural desmoid fibromatosis in familial adenomatous polyposis (FAP)/Turcot syndrome. Genomic analysis showing XRCC3 alterations suggested radiotherapy as contributing factor to the progression of LFS-associated medulloblastoma, and demonstrated different mechanisms of APC inactivation in the FAP-associated tumors. The integrated genomic-transcriptomic analysis uncovered the growth pathways driving tumorigenesis, including the prolactin-prolactin receptor (PRLR) autocrine loop and Shh pathway in the LFS-associated prolactinoma and medulloblastoma, respectively, the Wnt pathway in both FAP-associated neoplasms, and the TGFβ and Hippo pathways in the soft tissue tumors, regardless of germline predisposition. In addition, the comparative analysis of paired syndromic neoplasms revealed several growth pathways susceptible to therapeutic intervention by PARP, PRLR, and selective receptor tyrosine kinase (RTK) inhibitors. These could target the defective DNA damage repair in the LFS-associated medulloblastoma, the prolactin autocrine loop in the atypical prolactinoma, the EPHA3/7 and ALK overexpression in the FAP-associated medulloblastoma, and the multi-RTK upregulation in the soft tissue neoplasms. This study presents the spatiotemporal evolution of novel neoplastic associations in syndromic medulloblastoma, and discusses the post-radiotherapy risk for secondary malignancies in syndromic pediatric patients, with important implications for the biology, diagnosis, and therapy of these tumors.

Functional role and regulation of permeability-glycoprotein (P-gp) in the fetal membrane during drug transportation

OBJECTIVE

Na⁺ /H⁺ exchange regulatory factor-1 (NHERF-1) is a class I PDZ (PSD95/Discs-large/ZO-1) binding protein involved in cell-surface expression and stabilization of transporter proteins, including permeability-glycoprotein (P-gp) in various cell types. P-gp, expressed in placental trophoblasts, is an efflux transporter protein that influences the pharmacokinetics of various drugs used during pregnancy. Previously we have reported that NHERF-1 regulates fetal membrane inflammation. However, the role of NHERF-1 in regulating P-gp in the fetal membrane during drug transportation remains unclear. This study determined the interplay between NHERF-1 and P-gp in human fetal membrane cells.

METHODS

Fetal membranes from normal, term cesareans were screened for P-gp by immunohistochemistry (IHC). Chorionic trophoblast (CTC), with the highest expression of P-gp among fetal membrane cells, was further used to test interactive properties between NHERF-1 and P-gp. BeWo (placental trophoblast cell line) cells were used as a control. Immunoprecipitation (IP) of CTC lysates using the P-gp antibody followed by western blot determined co-precipitation of NHERF-1. Silencing NHERF-1 using small interfering RNA further tested the relevance of NHERF-1 in P-gp expression and function in CTC and BeWo cells. NHERF-1 regulation of P-gp's efflux function (drug resistance) was further tested using the ENZO^TM efflux dye kit.

RESULTS

Immunohistochemistry localized, and western blot confirmed P-gp in human fetal membranes, primarily in the CTC with limited expression in the amnion epithelial layer. P-gp expression in the membranes was similar to that seen in the placenta. IP data showed P-gp co-precipitating with NHERF1. Silencing of NHERF-1 resulted in significant drug resistance suggesting P-gp function mediated through NHERF1 in CTCs.

CONCLUSION

Proinflammatory mediator NHERF-1 regulates P-gp and control drug transportation across the fetal membranes. Our data suggest a novel functional role for fetal membranes during pregnancy. Besides the placenta, fetal membranes may also regulate efflux of materials at the feto-maternal interface and control drug transport during pregnancy.

Multi-Platform Classification of IDH-Wild-Type Glioblastoma Based on ERK/MAPK Pathway: Diagnostic, Prognostic and Therapeutic Implications

Glioblastoma is the most aggressive and frequent glioma in the adult population. Because current therapy regimens confer only minimal survival benefit, molecular subgrouping to stratify patient prognosis and therapy design is warranted. This study presents a multi-platform classification of glioblastoma by analyzing a large, ethnicity-inclusive 101-adult-patient cohort. It defines seven non-redundant IDH-wild-type glioblastoma molecular subgroups, G1-G7, corresponding to the upstream receptor tyrosine kinase (RTK) and RAS-RAF segment of the ERK/MAPK signal transduction pathway. These glioblastoma molecular subgroups are classified as G1/EGFR, G2/FGFR3, G3/NF1, G4/RAF, G5/PDGFRA, G6/Multi-RTK, and G7/Other. The comprehensive genomic analysis was refined by expression landscaping of all RTK genes, as well as of the major associated growth pathway mediators, and used to hierarchically cluster the subgroups. Parallel demographic, clinical, and histologic pattern analyses were merged with the molecular subgrouping to yield the first inclusive multi-platform classification for IDH-wild-type glioblastoma. This straightforward classification with diagnostic and prognostic significance may be readily used in neuro-oncological practice and lays the foundation for personalized targeted therapy approaches.

Magnetic Resonance Imaging (MRI) Differential Diagnosis of Meningiomas Using ANOVA

This work explored the diagnostic value of different subtypes of meningiomas under T2WI low signal based on analysis of variance (ANOVA), and the expression differences of Ki67, VEGF, and P73 in different subtypes were analyzed. 67 patients with meningioma confirmed surgically and pathologically in hospital were selected as the research subjects, whose pathological classification occurs with obvious low signal on T2WI. First, the age distribution of the subjects and the distribution of different subtypes were counted. Then, ANOVA was adopted to analyze the MRI imaging signs of patients with different subtypes of meningioma. Finally, the differences of Ki67, VEGF, and P73 proteins and mRNA expression levels in different subtypes were detected via immunohistochemical assay and qPCR. The results showed that the proportion of patients with transitional meningioma was the most, which was 43.28%, while the proportion of patients with meningeal melanoma was the least, which was 7.46%. In patients with transitional meningioma, the MRI images showed mixed signals in different layers. Fibrous MRI images showed hyalinosis and calcification of collagen fibers in the tumor, with low T2WI signal. Sand-shape MRI images showed double low signals. MRI images of meningeal melanoma showed high signal on T1-weighted Imaging (T1WI) and low signal on T2WI. The protein expression and mRNA levels of Ki67 and P73 in transitional meningioma were evidently higher in contrast to those in fibrous meningioma (P < 0.05). The expression level of VEGF protein and mRNA in meningeal melanoma were notably higher in contrast to those in fibro meningioma (P < 0.05). It was revealed that the MRI images of the four subtypes of meningiomas under ANOVA-based T2WI low signal were quite different, and the expressions of Ki67, P73, and VEGF in different subtypes had significant differences. This work provided a reference basis for the preoperative diagnosis, treatment, and prognosis of meningiomas.

Novel targetable FGFR2 and FGFR3 alterations in glioblastoma associate with aggressive phenotype and distinct gene expression programs

Prognostic molecular subgrouping of glioblastoma is an ongoing effort and the current classification includes IDH-wild-type and IDH-mutant entities, the latter showing significantly better prognosis. We performed a comparative integrated analysis of the FGFR glioblastoma subgroup consisting of 5 cases from a prospective 101-patient-cohort. FGFR alterations included FGFR2-TACC2 and FGFR2 amplifications arising in a multifocal IDH-mutant glioblastoma with unexpected 2.5-month patient survival, novel FGFR3 carboxy-terminal duplication and FGFR3-TLN1 fusion, and two previously described FGFR3-TACC3 fusions. The FGFR2 tumors showed additional mutations in SERPINE1/PAI-1 and MMP16, as part of extensive extracellular matrix remodeling programs. Whole transcriptomic analysis revealed common proliferation but distinct morphogenetic gene expression programs that correlated with tumor histology. The kinase program revealed EPHA3, LTK and ALK receptor tyrosine kinase overexpression in individual FGFR tumors. Paradoxically, all FGFR-fused glioblastomas shared strong PI3K and MAPK pathway suppression effected by SPRY, DUSP and AKAP12 inhibitors, whereas the FGFR2-TACC2 tumor elicited also EGFR suppression by ERRFI1 upregulation. This integrated analysis outlined the proliferation and morphogenetic expression programs in FGFR glioblastoma, and identified four novel, clinically targetable FGFR2 and FGFR3 alterations that confer aggressive phenotype and trigger canonical pathway feedback inhibition, with important therapeutic implications.

Sodium Hydrogen Exchanger Regulatory Factor-1 (NHERF1) Regulates Fetal Membrane Inflammation

The fetal inflammatory response, a key contributor of infection-associated preterm birth (PTB), is mediated by nuclear factor kappa B (NF-kB) activation. Na⁺/H⁺ exchanger regulatory factor-1 (NHERF1) is an adapter protein that can regulate intracellular signal transduction and thus influence NF-kB activation. Accordingly, NHERF1 has been reported to enhance proinflammatory cytokine release and amplify inflammation in a NF-kB-dependent fashion in different cell types. The objective of this study was to examine the role of NHERF1 in regulating fetal membrane inflammation during PTB. We evaluated the levels of NHERF1 in human fetal membranes from term labor (TL), term not in labor (TNIL), and PTB and in a CD1 mouse model of PTB induced by lipopolysaccharide (LPS). Additionally, primary cultures of fetal membrane cells were treated with LPS, and NHERF1 expression and cytokine production were evaluated. Gene silencing methods using small interfering RNA targeting NHERF1 were used to determine the functional relevance of NHERF1 in primary cultures. NHERF1 expression was significantly (p < 0.001) higher in TL and PTB membranes compared to TNIL membranes, and this coincided with enhanced (p < 0.01) interleukin (IL)-6 and IL-8 expression levels. LPS-treated animals delivering PTB had increased levels of NHERF1, IL-6, and IL-8 compared to phosphate-buffered saline (PBS; control) animals. Silencing of NHERF1 expression resulted in a significant reduction in NF-kB activation and IL-6 and IL-8 production as well as increased IL-10 production. In conclusion, downregulation of NHERF1 increased anti-inflammatory IL-10, and reducing NHERF1 expression could be a potential therapeutic strategy to reduce the risk of infection/inflammation associated with PTB.

Global activation of oncogenic pathways underlies therapy resistance in diffuse midline glioma

Diffuse midline gliomas (DMGs) are aggressive pediatric brain tumors with dismal prognosis due to therapy-resistant tumor growth and invasion. We performed the first integrated histologic/genomic/proteomic analysis of 21 foci from three pontine DMG cases with supratentorial dissemination. Histone H3.3-K27M was the driver mutation, usually at high variant allele fraction due to recurrent chromosome 1q copy number gain, in combination with germline variants in ATM, FANCM and MYCN genes. Both previously reported and novel recurrent copy number variations and somatic pathogenic mutations in chromatin remodeling, DNA damage response and PI3K/MAPK growth pathways were variably detected, either in multiple or isolated foci. Proteomic analysis showed global upregulation of histone H3, lack of H3-K27 trimethylation, and further impairment of polycomb repressive complex 2 by ASXL1 downregulation. Activation of oncogenic pathways resulted from combined upregulation of N-MYC, SOX2, p65/p50 NF-κB and STAT3 transcription factors, EGFR, FGFR2, PDGFRα/β receptor tyrosine kinases, and downregulation of PHLPP1/2, PTEN and p16/INK4A tumor suppressors. Upregulation of SMAD4, PAI-1, CD44, and c-SRC in multiple foci most likely contributed to invasiveness. This integrated comprehensive analysis revealed a complex spatiotemporal evolution in diffuse intrisic pontine glioma, recommending pontine and cerebellar biopsies for accurate populational genetic characterization, and delineated common signaling pathways and potential therapeutic targets. It also revealed an unsuspected activation of a multitude of oncogenic pathways, including cancer cell reprogramming, explaining the resistance of DMG to current therapies.

Multiple Occipital Bone Lytic Lesions Containing Ectopic Cerebellar Parenchyma Mimicking Neoplasia

BACKGROUND

Nonlethal neural tube defects are developmental malformations with complex pathogenesis usually manifested at birth or in childhood.

CASE DESCRIPTION

We report the case of a 61-year-old woman without significant previous clinical history presenting for neck pain and stiffness. An extensive workup detected multiple lytic lesions within the occipital bone and cervical vertebrae, suspicious for multiple myeloma or metastatic disease. Surgical resection of the occipital bone lesions revealed ectopic cerebellar tissue, some containing folia with mature cortical lamination, and no evidence of malignancy.

CONCLUSIONS

To our knowledge, this study describes the oldest individual presenting with ectopic cerebellar tissue and the only instance in which oncologic workup for malignancy was carried out prior to resection. It also proposes surgical resection as a diagnostic and curative approach for this complex basicranium and neural developmental defect, and discusses retinoic acid toxicity as a possible cause of its occurrence.

Genetic and histologic spatiotemporal evolution of recurrent, multifocal, multicentric and metastatic glioblastoma

Glioblastoma is the most frequent and aggressive primary brain tumor, characterized by extensive brain invasion and rarely, systemic metastases. The pathogenesis of metastatic glioblastoma is largely unknown. We present the first integrated clinical/histologic/genetic analysis of 5 distinct brain and lung foci from a unique case of recurrent, multifocal, multicentric and metastatic glioblastoma. The initial right frontotemporal gliosarcoma received standard surgical/chemoradiation therapy and recurred 1.5 years later, co-occurring with three additional masses localized to the ipsilateral temporal lobe, cerebellum and lung. Synchronous metastatic lung carcinoma was suspected in this long-term smoker patient with family history of cancer. However, glioblastoma was confirmed in all tumors, although with different morphologic patterns, including ependymomatous and epithelioid. Genomic profiling revealed a germline FANCD2 variant of unknown significance, and a 4-gene somatic mutation signature shared by all tumors, consisting of TERT promoter and PTEN, RB1 and TP53 tumor suppressor mutations. Additional GRIN2A and ATM heterozygous mutations were selected in the cerebellar and lung foci, but were variably present in the supratentorial foci, indicating reduced post-therapeutic genetic evolution in brain foci despite morphologic variability. Significant genetic drift characterized the lung metastasis, likely explaining the known resistance of circulating glioblastoma cells to systemic seeding. MET overexpression was detected in the initial gliosarcoma and lung metastasis, possibly contributing to invasiveness. This comprehensive analysis sheds light on the temporospatial evolution of glioblastoma and underscores the importance of genetic testing for diagnosis and personalized therapy.

Mutation Status and Epithelial Differentiation Stratify Recurrence Risk in Chordoid Meningioma-A Multicenter Study with High Prognostic Relevance

Chordoid meningioma is a rare WHO grade II histologic variant. Its molecular alterations or their impact on patient risk stratification have not been fully explored. We performed a multicenter, clinical, histological, and genomic analysis of chordoid meningiomas from 30 patients (34 tumors), representing the largest integrated study to date. By NHERF1 microlumen immunohistochemical detection, three epithelial differentiation (ED) groups emerged: #1/fibroblastic-like, #2/epithelial-poorly-differentiated and #3/epithelial-well-differentiated. These ED groups correlated with tumor location and genetic profiling, with NF2 and chromatin remodeling gene mutations clustering in ED group #2, and TRAF7 mutations segregating in ED group #3. Mutations in LRP1B were found in the largest number of cases (36%) across ED groups #2 and #3. Pathogenic ATM and VHL germline mutations occurred in ED group #3 patients, conferring an aggressive or benign course, respectively. The recurrence rate significantly correlated with mutations in NF2, as single gene, and with mutations in chromatin remodeling and DNA damage response genes, as groups. The recurrence rate was very high in ED group #2, moderate in ED group #3, and absent in ED group #1. This study proposes guidelines for tumor recurrence risk stratification and practical considerations for patient management.

Mutations of the MAPK/TSC/mTOR pathway characterize periventricular glioblastoma with epithelioid SEGA-like morphology-morphological and therapeutic implications

Epithelioid glioblastoma is a recognized glioblastoma variant, recently added to the World Health Organization brain tumor classification, with similar prognosis as the classic variant and B-Raf V600E mutations in 50% of the cases. We identified a new subset of epithelioid glioblastoma with periventricular location and subependymal giant cell astrocytoma (SEGA)-like morphology. Genomic profiling of these tumors revealed driver mutations in NF1, subclonal mutations in TSC1, and a novel driver mutation in MTOR, suggesting upregulation of the MAPK/TSC1/mTOR pathway. Strong mTOR activation was confirmed by immunohistochemistry for the mTOR kinase target 4E-BP1. TSC1 and MTOR mutations have been previously described in low-grade glioma, such as SEGA, and focal cortical dysplasia, respectively, that display large cells with abundant cytoplasm, most likely resulting from the biogenetic signaling of mTOR. Unlike these, the mutations in SEGA-like glioblastoma occurred in the context of other genetic aberrations present in high-grade neoplasms, including in the CDKN2A/B, PIK3R1, PIK3CA and EGFR genes. For one patient with two temporally distinct specimens, the subclonal TSC1 pathogenic mutation was detected only in the specimen showing SEGA-like morphology, indicating requirement for mTOR activation as trigger for specific epithelioid/SEGA-like morphology. As FDA-approved kinase inhibitors are available and target many steps of the MAPK/mTOR pathway, recognition of this new subset of periventricular high-grade gliomas with clear phenotypic-genotypic correlates is essential for prompt biomarker testing and appropriate targeted therapeutic management of these patients.