Identification of novel diagnostic markers for choroid plexus tumors: a microarray-based approach

Correlation between choroid plexus carcinoma and Li-Fraumeni syndrome: implications of TP53 mutations and management strategies-a case-based narrative review

BACKGROUND

Choroid plexus carcinomas (CPCs) are rare, aggressive grade 3 tumors of the central nervous system associated with Li-Fraumeni syndrome (LFS) in a notable percentage of cases due to TP53 germline mutations. Understanding the correlation between CPCs and LFS is crucial for tailored management strategies. However, distinguishing CPCs from benign choroid plexus papillomas (CPPs) remains challenging, relying largely on histologic features. This study aimed to explore the association between CPCs and LFS, emphasizing the impact of TP53 mutations on diagnosis, treatment, and clinical outcomes.

MATERIALS AND METHODS

Scientific databases such as PubMed, Scopus, and Web of Science were systematically searched up to January 2024 using keywords related to CPCs, LFS, TP53 mutation, and central nervous system tumors. Selection criteria included studies investigating the link between CPCs and LFS, their management approaches, and genetic implications of TP53 mutations. Ten relevant studies were selected for analysis after screening titles, abstracts, and full-text articles. Data extraction focused on clinical, genetic, and management factors related to CPCs associated with LFS.

RESULTS

The review highlighted the strong association (36%) between CPCs and LFS, primarily due to TP53 germline mutations. Studies emphasized the need for genetic testing in patients with CPCs, especially in pediatric cases, to identify LFS implications. Furthermore, the impact of TP53 mutations on treatment strategies was emphasized, recommending irradiation-sparing therapies due to inferior survival rates associated with radiotherapy in LFS patients with CPCs. Cases illustrated the challenges in diagnosing CPCs and the importance of immunohistochemistry and genetic testing for TP53 mutations.

CONCLUSION

CPCs pose challenges in diagnosis and management, particularly in distinguishing them from benign tumors. The association with LFS, often due to TP53 germline mutations, underscores the importance of genetic testing for early detection and tailored treatment strategies. Irradiation-sparing therapies are recommended for LFS-associated CPCs to mitigate the risk of secondary malignancies. Comprehensive profiling of CPC patients, especially in pediatric cases, is crucial for early detection and management of potential secondary cancers associated with LFS.

The composition of choroid plexus tumor research: a bibliometric analysis of the 100 most impactful studies to date

PURPOSE

Choroid plexus tumors (CPT) are relatively rare CNS tumors that primarily occur in children. They are classified as low-grade choroid plexus papilloma, including atypical ones, and high-grade choroid plexus carcinoma based on histological characteristics. There has been extensive academic research regarding these complex tumors. The goal of this work was to identify the 100 most-cited articles pertaining to CPTs in order to better understand the most impactful studies to date.

METHODS

In August 2023, Elsevier's Scopus database was searched for the 100 most-cited articles about CPT. To look for trends, articles were classified as either basic science or clinical, and the earliest 50 articles were separated from the latest 50 articles and then were compared. Various bibliometric parameters were summarized and compared using Pearson's chi-square exact test and Wilcoxon rank sum test/Mann-Whitney U test.

RESULTS

The 100 most-cited articles were published between 1955 and 2016 in 53 different scientific journals, originating from 16 distinct countries. Over 75% of the articles were clinical in nature, and overall mean (range) values were as follows: citation count 78.5 (42-371), citation rate per year 3.4 (0.9-12), number of authors 6.2 (1-28). Newer articles had statistically higher citation rate (P < 0.01) and number of authors (P < 0.01) compared to their older counterparts. Additionally, while there was no significant difference in article focus (P = 0.64), there was a difference in study design (P < 0.01).

CONCLUSION

This study used citation number as a surrogate for article impact and identified the 100 most-cited CPT articles. New mutational analyses have allowed for further subgrouping and positive trends in collaboration shine hope for improvement in treatment outcomes and long-term survival.

Blood proteome of acute intracranial hemorrhage in infant victims of abusive head trauma

Abusive head trauma (AHT) is a leading cause of mortality and morbidity in infants. While the reported incidence is close to 40 cases per 100'000 births/year, misdiagnoses are commonly observed in cases with atypical, subacute, or chronic presentation. Currently, standard clinical evaluation of inflicted intracranial hemorrhagic injury (ICH) in infants urgently requires a screening test able to identify infants who need additional investigations. Blood biomarkers characteristic of AHT may assist in detecting these infants, improving prognosis through early medical care. To date, the application of innovative omics technologies in retrospective studies of AHT in infants is rare, due also to the blood serum and cerebrospinal fluid of AHT cases being scarce and not systematically accessible. Here, we explored the circulating blood proteomes of infants with severe AHT and their atraumatic controls. We discovered 165 circulating serum proteins that display differential changes in AHT cases compared with atraumatic controls. The peripheral blood proteomes of pediatric AHT commonly reflect: (i) potentially secreted proteome from injured brain, and (ii) proteome dysregulated in the system's circulation by successive biological events following acute ICH. This study opens up a novel opportunity for research efforts in clinical screening of AHT cases.

Intracranial Subdural Fluid Accumulation Associated with a Choroid Plexus Carcinoma in a Dog

Choroid plexus tumors are commonly described as intraventricular mass lesions and account for 7-10% of intracranial, primary tumors in dogs. A 3-year-old Shetland sheepdog was presented with a history of slowly progressive lethargy, vision impairment and cognitive deficits. On magnetic resonance imaging, a subdural fluid accumulation (SFA) overlying and compressing the left parietotemporal lobe as well as multifocal changes consisting of cyst-like lesions, supposed intra-axial brain lesions and mild, multifocal meningeal thickening and generalized contrast enhancement were identified. Cerebrospinal fluid (CSF) analysis showed a mononuclear pleocytosis with negative results for infectious agents. The dog was treated with prednisolone followed by burr hole craniotomy with puncture of the SFA, which macroscopically appeared to be CSF-like fluid. After initial improvement, the dog deteriorated despite continuation of prednisolone and cytarabine therapy and was euthanized four weeks after surgery. Histopathology was consistent with a disseminated, neuroinvasive choroid plexus carcinoma (CPC) that involved the entire neuroaxis including the meninges of the brain and spinal cord. Immunohistochemical examination showed a strong Kir7.1 and a heterogenous cytokeratin-immunoreactivity in neoplastic cells. In conclusion, a CPC should be considered as a possible cause of a SFA even in the absence of an intraventricular mass lesion.

Potassium Channels as a Target for Cancer Therapy: Current Perspectives

Potassium (K⁺) channels are highly regulated membrane proteins that control the potassium ion flux and respond to different cellular stimuli. These ion channels are grouped into three major families, Kv (voltage-gated K⁺ channel), Kir (inwardly rectifying K⁺ channel) and K2P (two-pore K⁺ channels), according to the structure, to mediate the K⁺ currents. In cancer, alterations in K⁺ channel function can promote the acquisition of the so-called hallmarks of cancer – cell proliferation, resistance to apoptosis, metabolic changes, angiogenesis, and migratory capabilities – emerging as targets for the development of new therapeutic drugs. In this review, we focus our attention on the different K⁺ channels associated with the most relevant and prevalent cancer types. We summarize our knowledge about the potassium channels structure and function, their cancer dysregulated expression and discuss the K⁺ channels modulator and the strategies for designing new drugs.

Bovine intracranial neoplasia: A retrospective case series

This case series describes the clinical and pathological findings of intracranial neoplasms in cattle, a rare entity. Data and archived tissues from 24 intracranial tumors were reviewed and investigated by immunohistochemistry for S100, glial fibrillary acidic protein, synaptophysin, pancytokeratin, vimentin, neuron-specific enolase, oligodendrocyte transcription factor 2, and isocitrate dehydrogenase 1. Ages of affected cattle ranged from 6 months to 14 years (5.7 ± 3.6 years; mean ± SD). Predominant clinical signs were altered mental state, central vestibular dysfunction, and cerebellar incoordination. Twelve gliomas, all high grade, were the most common tumors observed: oligodendrogliomas (n = 6), astrocytomas (n = 4), and undefined gliomas (n = 2). The oligodendrogliomas were located in the brainstem and extended into the ventricles, whereas all astrocytomas were located in the forebrain. Isocitrate dehydrogenase 1 gene mutation as described in humans was not detected. The 5 meningiomas exhibited microcystic, chordoid, atypical, papillary, and anaplastic subtypes. Metastatic carcinomas (n = 4) were the only secondary tumor type present, and these were located at the level of the medulla with infiltration of cranial nerves and in one case leptomeningeal carcinomatosis. In addition, 2 medulloblastomas and 1 choroid plexus carcinoma were diagnosed. Immunohistochemistry for vimentin and pancytokeratin was particularly useful to distinguish meningiomas and choroid plexus carcinoma (positive for vimentin only) from mestastatic carcinomas (positive for cytokeratin only) as all showed a papillary growth pattern. Overall, the morphological features were comparable with other species and the human and canine classifications could be applied.

Kir Channel Molecular Physiology, Pharmacology, and Therapeutic Implications

For the past two decades several scholarly reviews have appeared on the inwardly rectifying potassium (Kir) channels. We would like to highlight two efforts in particular, which have provided comprehensive reviews of the literature up to 2010 (Hibino et al., Physiol Rev 90(1):291-366, 2010; Stanfield et al., Rev Physiol Biochem Pharmacol 145:47-179, 2002). In the past decade, great insights into the 3-D atomic resolution structures of Kir channels have begun to provide the molecular basis for their functional properties. More recently, computational studies are beginning to close the time domain gap between in silico dynamic and patch-clamp functional studies. The pharmacology of these channels has also been expanding and the dynamic structural studies provide hope that we are heading toward successful structure-based drug design for this family of K⁺ channels. In the present review we focus on placing the physiology and pharmacology of this K⁺ channel family in the context of atomic resolution structures and in providing a glimpse of the promising future of therapeutic opportunities.

Advancing brain barriers RNA sequencing: guidelines from experimental design to publication

BACKGROUND

RNA sequencing (RNA-Seq) in its varied forms has become an indispensable tool for analyzing differential gene expression and thus characterization of specific tissues. Aiming to understand the brain barriers genetic signature, RNA seq has also been introduced in brain barriers research. This has led to availability of both, bulk and single-cell RNA-Seq datasets over the last few years. If appropriately performed, the RNA-Seq studies provide powerful datasets that allow for significant deepening of knowledge on the molecular mechanisms that establish the brain barriers. However, RNA-Seq studies comprise complex workflows that require to consider many options and variables before, during and after the proper sequencing process.

MAIN BODY

In the current manuscript, we build on the interdisciplinary experience of the European PhD Training Network BtRAIN ( https://www.btrain-2020.eu/ ) where bioinformaticians and brain barriers researchers collaborated to analyze and establish RNA-Seq datasets on vertebrate brain barriers. The obstacles BtRAIN has identified in this process have been integrated into the present manuscript. It provides guidelines along the entire workflow of brain barriers RNA-Seq studies starting from the overall experimental design to interpretation of results. Focusing on the vertebrate endothelial blood-brain barrier (BBB) and epithelial blood-cerebrospinal-fluid barrier (BCSFB) of the choroid plexus, we provide a step-by-step description of the workflow, highlighting the decisions to be made at each step of the workflow and explaining the strengths and weaknesses of individual choices made. Finally, we propose recommendations for accurate data interpretation and on the information to be included into a publication to ensure appropriate accessibility of the data and reproducibility of the observations by the scientific community.

CONCLUSION

Next generation transcriptomic profiling of the brain barriers provides a novel resource for understanding the development, function and pathology of these barrier cells, which is essential for understanding CNS homeostasis and disease. Continuous advancement and sophistication of RNA-Seq will require interdisciplinary approaches between brain barrier researchers and bioinformaticians as successfully performed in BtRAIN. The present guidelines are built on the BtRAIN interdisciplinary experience and aim to facilitate collaboration of brain barriers researchers with bioinformaticians to advance RNA-Seq study design in the brain barriers community.

Next generation DNA sequencing of atypical choroid plexus papilloma of brain: Identification of novel mutations in a female patient by Ion Proton

Choroid plexus papilloma (CPP) is a rare benign tumor of the central nervous system that is usually confined to the cerebral ventricles. According to the World Health Organization, CPP corresponds to a grade I atypical CPP (a-CPP); however, it can become more aggressive and reach grade II, which can rarely undergo malignant transformation into a choroid plexus carcinoma (grade III). To the best of our knowledge, identification of these tumors mutations by next generation DNA sequencing (NGS) has not been yet reported. In the present study, NGS analysis of an a-CPP case was performed. Data were analyzed using Advaita Bioinformatics i-VariantGuide and Ion Reporter 5.6 programs. The results from NGS identified 12 novel missense mutations in the following genes: NOTCH1, ATM, STK36, MAGI1, DST, RECQL4, NUMA1, THBS1, MYH11, MALT1, SMARCA4 and CDH20. The PolyPhen score of six variants viz., DST, RECQL4, NUMA1, THBS1, MYHI1 and SMARCA4 were high, which suggested these variants represents pathogenic variants. Two novel insertions that caused frameshift were also found. Furthermore, two novel nonsense mutations and 14 novel intronic variants were identified in this tumor. The novel missense mutation detected in ATM gene was situated in c.5808A>T; p. (Leu1936Phe) in exon 39, and a known ATM mutation was in c.5948A>G; p. (Asn1983Ser). These novel mutations had not been reported in previous database. Subsequently, the quality statistics of these variants, including allele coverage, allele ratio, P-value, Phred quality score, sequencing coverage, PolyPhen score and alleles frequency was performed. For all variants, P-value was highly significant and the Phred quality score was high. In addition, the results from sequencing coverage demonstrated that 97.02% reads were on target and that 97.88% amplicons had at least 500 reads. These findings may serve at determining new strategies to distinguish the types of choroid plexus tumor, and at developing novel targeted therapies. Development of NGS technologies in the Kingdom of Saudi Arabia may be used in molecular pathology laboratories.

Clinicopathologic Features, Diagnosis, and Characterization of the Immune Cell Population in Canine Choroid Plexus Tumors

The World Health Organization characterizes human choroid plexus tumor (CPT) as papilloma (CPP), atypical CPP (ACPP), and carcinoma (CPC). CPCs can disseminate via cerebrospinal fluid and be mistaken for metastatic carcinoma, creating a diagnostic challenge. Kir7.1 immunohistochemistry (IHC) is a highly reliable tool for diagnostic confirmation of CPTs and their differentiation from metastatic carcinomas in human beings and dogs. This study describes the neuropathology, Kir7.1 staining profile, and the immune cell population within the tumor microenvironment in 11 CPTs in dogs. Archived tissue sections with a diagnosis of CPT were examined and immunolabelled with Kir7.1 for diagnostic confirmation. The number of Ki67-positive neoplastic cells was calculated in 2.4 mm² (equivalent to 10 FN22/40X fields), and a mean value was generated for each neoplasm. IHC for CD3, CD20, MAC387, and Iba1 was performed for immune cell characterization, and the number of stained cells for each antibody was counted in 2.4 mm², generating individual cumulative values for each antibody. T-tests with Bonferroni correction evaluated IHC differences between tumor types, and Spearman's rank correlations evaluated relationships among IHC markers. Kir7.1 immunoreactivity was intense at the apical cell membrane in CPPs and ACPPs, and at the apical cell membrane and cytoplasm in CPCs. Ki67 immunoreactivity was detected in all cases. CD3+ and CD20+ lymphocytes trended together (p = 0.005) and were present within and around all CPTs. Five cases had intravascular MAC387+ monocytes. Iba1 immunoreactivity was robust within and around all tumors. Statistical differences in immune cell markers were not found among tumor types. As previously reported, Kir7.1 is a reliable antibody for the diagnosis of canine CPTs. Although immune cells were present in all cases, no significant associations were found between the type of cells and tumor diagnosis. The characterization of the immune cells within CPTs could be useful in future studies involving immunotherapy.

Quantitative Evaluation of Different Protein Fractions of Cerebrospinal Fluid Using 18O Labeling

Molecular analysis of cerebrospinal fluid (CSF) provides comprehensive information on physiological and pathological processes related to the brain. In particular, proteomic studies give insights into the pathogenesis of many brain diseases which still pose diagnostic and therapeutic challenges. The identification of reliable biomarkers is an important step to meet these challenges. Mass spectrometry is an essential proteomic tool, not only for highly sensitive identification of proteins and posttranslational modifications, but also for their reliable quantification. Here, ¹⁸O labeling of tryptic peptides was employed to qualitative and quantitative analyses of protein fractions obtained by depletion of highly abundant proteins from cerebrospinal fluid. It was found that the execution of the investigated depletion protocols may cause the loss of potential protein biomarkers of neurological diseases.

Characterization of the EF-Hand Calcium-Binding Domains of Human Plastins

The three human plastins (L-plastin, T-plastin, and I-plastin) are important regulatory Ca²⁺-binding proteins that belong to the family of actin-binding proteins. Plastins are involved in the regulation of the actin cytoskeleton as well as the cross-linking of actin filaments. In addition to four calponin-homology (CH) domains, all three plastins contain two N-terminal EF-hand Ca²⁺-binding motifs which together are homologous to a single lobe of the well-known calcium-regulatory protein calmodulin. This part of the protein allows for the regulation of the actin bundling activity in response to elevated calcium levels. In this protocol, we describe the purification of the EF-hand headpiece domains of all three plastins, as well as SPR studies, ITC studies, and NMR interaction studies with different peptides and calcium. In combination, these three experimental techniques provide detailed insights into a novel regulatory mechanism, involving the linker region between the EF-hand domain and the first CH domain of the plastins.

Incorporating Advances in Molecular Pathology Into Brain Tumor Diagnostics

Recent advances in molecular pathology have reshaped the practice of brain tumor diagnostics. The classification of gliomas has been restructured with the discovery of isocitrate dehydrogenase (IDH) 1/2 mutations in the vast majority of lower grade infiltrating gliomas and secondary glioblastomas (GBM), with IDH-mutant astrocytomas further characterized by TP53 and ATRX mutations. Whole-arm 1p/19q codeletion in conjunction with IDH mutations now define oligodendrogliomas, which are also enriched for CIC, FUBP1, PI3K, NOTCH1, and TERT-p mutations. IDH-wild-type (wt) infiltrating astrocytomas are mostly primary GBMs and are characterized by EGFR, PTEN, TP53, NF1, RB1, PDGFRA, and CDKN2A/B alterations, TERT-p mutations, and characteristic copy number alterations including gains of chromosome 7 and losses of 10. Other clinically and genetically distinct infiltrating astrocytomas include the aggressive H3K27M-mutant midline gliomas, and smaller subsets that occur in the setting of NF1 or have BRAF V600E mutations. Low-grade pediatric gliomas are both genetically and biologically distinct from their adult counterparts and often harbor a single driver event often involving BRAF, FGFR1, or MYB/MYBL1 genes. Large scale genomic and epigenomic analyses have identified distinct subgroups of ependymomas tightly linked to tumor location and clinical behavior. The diagnosis of embryonal neoplasms also integrates molecular testing: (I) 4 molecularly defined, biologically distinct subtypes of medulloblastomas are now recognized; (II) 3 histologic entities have now been reclassified under a diagnosis of "embryonal tumor with multilayered rosettes (ETMR), C19MC-altered"; and (III) atypical teratoid/rhabdoid tumors (AT/RT) now require SMARCB1 (INI1) or SMARCA4 (BRG1) alterations for their diagnosis. We discuss the practical use of contemporary biomarkers for an integrative diagnosis of central nervous system neoplasia.

OTX2 Defines a Subgroup of Atypical Teratoid Rhabdoid Tumors With Close Relationship to Choroid Plexus Tumors

Atypical teratoid rhabdoid tumors (ATRT) are highly malignant brain tumors of early childhood that have been regarded as a homogenous entity characterized by inactivation of the SMARCB1/INI1 or SMARCA4/BRG1 genes as the only characteristic alteration. Recent studies suggest that similar to other embryonal tumors ATRT can also be divided into subgroups based on their mRNA or methylation profiles. Using microarray-based expression analysis of 12 patient ATRT specimens we demonstrated the existence of 2 subgroups of ATRT. One subgroup is characterized by high expression of OTX2, encoding a transcription factor involved in brain development. OTX2 expression was verified by immunohistochemistry and might function as a novel therapeutic target for this fatal tumor. High expression of OTX2 as well as expression of Kir7.1/KCNJ13, TRPM3 and ENPP2, which have all previously been linked to either choroid plexus epithelium or choroid plexus tumors (CPTs), suggests a close histogenetic relation of this subgroup to CPTs.

NHERF1/EBP50 and NF2 as diagnostic markers for choroid plexus tumors

The adaptor protein NHERF1 (Na/H exchanger-3 regulatory factor-1) and its associated ezrin-radixin-moesin-merlin/neurofibromin-2 (ERM-NF2) family proteins are required for epithelial morphogenesis and have been implicated in cancer progression. NHERF1 is expressed in ependymal cells and constitutes a highly sensitive diagnostic marker for ependymoma, where it labels membrane polarity structures. Since NHERF1 and ERM-NF2 proteins show polarized expression in choroid plexus (CP) cells, we tested their diagnostic utility in CP neoplasms. NHERF1 immunohistochemistry in 43 adult and pediatric tumors with papillary morphology revealed strong apical plasma membrane staining in CP papilloma (WHO grade I) and cytoplasmic expression in CP carcinoma (WHO grade III). Ezrin and moesin showed similar but less distinctive staining. NHERF1 also labeled papillary tumors of the pineal region in a microlumen and focal apical membrane pattern, suggestive of a transitional morphology between CP papilloma and ependymoma. CP tumors of all grades could be differentiated from metastatic carcinomas with papillary architecture by NF2, which showed polarized membranous staining in CP tumors. NHERF1 and NF2 immunohistochemistry showed enhanced sensitivity and specificity for CP tumors compared to commonly used markers, including cytokeratins and Kir7.1, emerging as reliable diagnostic tools for the differential diagnosis of papillary tumors of the central nervous system.

Kir7.1 immunoreactivity in canine choroid plexus tumors

Choroid plexus neoplasms are uncommon brain tumors in dogs. Choroid plexus carcinomas often spread diffusely throughout the ventricular system and subarachnoid space and, in aggressive forms, can mimic histologic patterns of other carcinomas, including being embedded in a desmoplastic reaction. Although choroid plexus tumors (CPTs) heterogeneously express pan-cytokeratin, little is known about other markers to identify choroid plexus and their associated tumors. Kir7.1, an inward-rectifier potassium channel, is reported to have high diagnostic utility in human neuropathology to distinguish CPTs from other primary brain tumors and cerebral metastases. To determine Kir7.1 expression in the dog brain, we analyzed the immunoreactivity of Kir7.1 in normal brain, gliomas, ependymomas, CPTs, meningiomas, and carcinomas. In normal brain tissue, the immunostaining was restricted to the choroid plexus where there was robust membrane immunoreactivity along the apical border of the cells with less intense cytoplasmic staining. Similar strong immunoreactivity was detected in 12 of 12 CPTs, whereas 5 of 5 gliomas, 4 of 5 ependymomas, 5 of 5 meningiomas, and 5 of 6 carcinomas had no immunoreactivity. One ependymoma and 1 nasal carcinoma with squamous metaplasia were up to 75% immunopositive, with moderate cytoplasmic and membranous immunoreactivity, but lacking the robust apical immunoreactivity pattern. Analysis for immunoreactivity in a tissue microarray failed to yield any other locations in which immunoreactivity was detected. These results, including the distinctive pattern of immunostaining in CPTs, suggest that Kir7.1 is an excellent marker for CPTs in the dog.

Choroid plexus papilloma in a beluga whale (Delphinapterus leucas)

We report herein a choroid plexus papilloma in a beluga whale ( Delphinapterus leucas). This case was positive for choroid plexus tumor marker Kir7.1 on immunohistochemistry. These results and the high conservation of Kir7.1 across species at the amino acid sequence level strongly suggest that antibodies directed against Kir7.1 not only can be employed for the diagnosis of choroid plexus tumors in cetaceans, but are also likely to be diagnostically useful in other animal species.

Depletion of highly abundant proteins from human cerebrospinal fluid: a cautionary note

Affinity-based techniques, both for enrichment or depletion of proteins of interest, suffer from unwanted interactions between the bait or matrix material and molecules different from the original target. This effect was quantitatively studied by applying two common procedures for the depletion of albumin/gamma immunoglobulin to human cerebrospinal fluid. Proteins of the depleted and the column-bound fraction were identified by mass spectrometry, employing (18)O labeling for quantitation of their abundance. To different extents, the depletion procedures caused the loss of proteins previously suggested as biomarker candidates for neurological diseases. This is an important phenomenon to consider when quantifying protein levels in biological fluids.

Cytoplasmic 5-Lipoxygenase Staining Is a Highly Sensitive Marker of Human Tumors of the Choroid Plexus

OBJECTIVES

To determine the immunoreactivity status of 5-lipoxygenase (5-LO) in normal tissues, in tumors of the human choroid plexus, and in other brain tumors.

METHODS

In total, 135 cases of various types of brain tumors were selected. Tissue samples were immunostained with a rabbit polyclonal anti-5-LO antibody.

RESULTS

Nuclear reactivity was observed in most brain tumors, with most of the positive tumor cells exhibiting low-level reactivity. Cytoplasmic strong immunoreactivity for 5-LO (2+ or 3+) was only observed in 8.8% of astrocytic tumors, 0% of oligodendrogliomatous tumors, 5.6% of ependymal tumors, 0% of embryonal tumors, 3.1% of meningeal tumors, and 0% of metastatic lung adenocarcinomas. In contrast, cytoplasmic immunoreactivity for 5-LO was detected in all 27 cases of choroid plexus tumors. Twenty-five cases showed strong and diffuse cytoplasmic immunoreactivity.

CONCLUSIONS

Our findings indicate that cytoplasmic 5-LO immunoreactivity is highly characteristic of human choroid plexus tumors but not other central nervous system tumor types. Cytoplasmic staining for 5-LO may prove to be a useful immunoreactive marker in the diagnosis of choroid plexus tumors.

Stanniocalcin-1, a new biomarker of glioma progression, is associated with prognosis of patients

Stanniocalcin-1 (STC1) is a secreted glycoprotein hormone and highly expressed in various types of human malignancies. Although evidence points to the role of STC1 in human cancers, the clinical significance of STC1 expression in glioma has not been established. Here, we investigated the relationship between STC1 expression and clinicopathological significance in glioma. In our study, we selected 60 cases of different grades glioma tissues to detect the expression of STC1. Data showed that the mRNA and protein levels of STC1 in high-grade glioma tissues were significantly higher than that in low-grade tissues. The results of double immunofluorescent staining disclosed STC1 distribution in vascular endothelial cells and the cytoplasm in high-grade glioma, but almost distributed only in vascular endothelial cells in low-grade glioma. By immunohistochemistry, we got the same results and the expression of STC1 has significant difference in high-grade gliomas and low-grade gliomas. Furthermore, the results of Kaplan-Meier analysis indicated that cases with high STC1expression had significantly worse overall survival than those with low level of STC1. These results suggested that STC1 may be a valuable biomarker in diagnosing malignant degree of glioma and evaluating prognostic following surgery. Next, we would study the pathophysiological mechanism of STC1 in glioma.

Anatomical, molecular and pathological consideration of the circumventricular organs

BACKGROUND AND PURPOSE

Circumventricular organs (CVOs) are a diverse group of specialised structures characterized by peculiar vascular and position around the third and fourth ventricles of the brain. In humans, these organs are present during the fetal period and some become vestigial after birth. Some, such as the pineal gland (PG), subcommissural organ (SCO) and organum vasculosum of the lamina terminalis (OVLT), which are located around the third ventricle, might be the site of origin of periventricular tumours. In contrast to humans, CVOs are present in the adult rat and can be dissected by laser capture microdissection (LCM).

METHODS

In this study, we used LCM and microarrays to analyse the transcriptomes of three CVOs, the SCO, the subfornical organ (SFO) and the PG and the third ventricle ependyma of the adult rat, in order to better characterise these organs at the molecular level. Furthermore, an immunohistochemical study of Claudin-3 (CLDN3), a membrane protein involved in forming cellular tight junctions, was performed at the level of the SCO.

RESULTS

This study highlighted some potentially new or already described specific markers of these structures as Erbb2 and Col11a1 in ependyma, Epcam and CLDN3 in the SCO, Ren1 and Slc22a3 in the SFO and Tph, Anat and Asmt in the PG. Moreover, we found that CLDN3 expression was restricted to the apical pole of ependymocytes in the SCO.

Choroid plexus carcinomas are characterized by complex chromosomal alterations related to patient age and prognosis

Choroid plexus carcinoma is a malignant brain tumor predominantly occurring in young children. Only limited data are available regarding the underlying molecular genetic alterations. Therefore, molecular inversion probe single nucleotide polymorphism (MIP SNP) arrays were performed on a series of 26 neuropathologically well-characterized choroid plexus carcinomas. Recurrent copy number losses of chromosomes 5, 6, 16, 18, 19, and 22 as well as gains of chromosomes 1, 2, 4, 12, and 20 were identified. Furthermore, GISTIC analysis identified significant recurrent gains of 17 genes in 9 regions, and recurrent losses of 96 genes in 14 regions. Clustering analysis separated choroid plexus carcinomas into two groups: one characterized by marked losses and the other characterized by gains across the chromosomes. Chromosomal losses of 9, 19p, and 22q were significantly more frequent in younger children (<36 months), whereas gains on chromosomes 7 and 19, and chromosome arms 8q, 14q, and 21q prevailed in older patients. Multivariate analysis revealed that loss of 12q was associated with shorter survival [12 ± 5 months vs. 86 ± 8 months; (mean ± SD; P = 0.001)] and, in addition, 45 smaller chromosomal regions showing genetic alterations significantly associated with survival could be identified. The MIP SNP array profiles also contributed to the diagnosis of two difficult SMARCB1-negative tumors as choroid plexus carcinoma and cribriform neuroepithelial tumor (CRINET), respectively. In conclusion, choroid plexus carcinomas are characterized by complex genetic alterations, which are related to patient age and may have prognostic and diagnostic value.

Gene expression-based comparison of the human secretory neuroepithelia of the brain choroid plexus and the ocular ciliary body: potential implications for glaucoma

Background

The neuroepithelia of the choroid plexus (CP) in the brain and the ciliary body (CB) of the eye have common embryological origins and share similar micro-structure and functions. The CP epithelium (CPE) and the non-pigmented epithelium (NPE) of the CB produce the cerebrospinal fluid (CSF) and the aqueous humor (AH) respectively. Production and outflow of the CSF determine the intracranial pressure (ICP); production and outflow of the AH determine the intraocular pressure (IOP). Together, the IOP and ICP determine the translaminar pressure on the optic disc which may be involved in the pathophysiology of primary open angle glaucoma (POAG). The aim of this study was to compare the molecular machinery of the secretory neuroepithelia of the CP and CB (CPE versus NPE) and to determine their potential role in POAG.

Methods

We compared the transcriptomes and functional annotations of healthy human CPE and NPE. Microarray and bioinformatic studies were performed using an Agilent platform and the Ingenuity Knowledge Database (IPA).

Results

Based on gene expression profiles, we found many similar functions for the CPE and NPE including molecular transport, neurological disease processes, and immunological functions. With commonly-used selection criteria (fold-change > 2.5, p-value < 0.05), 14% of the genes were expressed significantly differently between CPE and NPE. When we used stricter selection criteria (fold-change > 5, p-value < 0.001), still 4.5% of the genes were expressed differently, which yielded specific functions for the CPE (ciliary movement and angiogenesis/hematopoiesis) and for the NPE (neurodevelopmental properties). Apart from a few exceptions (e.g. SLC12A2, SLC4A4, SLC4A10, KCNA5, and SCN4B), all ion transport protein coding genes involved in CSF and AH production had similar expression profiles in CPE and NPE. Three POAG disease genes were expressed significantly higher in the CPE than the NPE, namely CDH1, CDKN2B and SIX1.

Conclusions

The transcriptomes of the CPE and NPE were less similar than we previously anticipated. High expression of CSF/AH production genes and candidate POAG disease genes in the CPE and NPE suggest that both might be involved in POAG.

Current management of choroid plexus carcinomas

Choroid plexus carcinoma (CPC) is a World Health Organization (WHO) grade III brain tumor with a poor prognosis that occurs mainly in children. Gross total resection of CPC is highly recommended and is associated with improved overall survival, although it is often associated with increased morbidity. The use of adjuvant therapies has yet to be standardized, although evidence suggests that for patients with incompletely resected CPCs, a combination of chemotherapy and radiation therapy may be beneficial. The use of radiation therapy for younger children (<3 years old) with CPC, however, is not recommended, due to the potential negative neurological sequelae associated with radiation to the developing brain. Given that the majority of CPC patients are young children, questions regarding optimal radiation dose, chemotherapy agents, and how to combine these two adjuvant treatment modalities to achieve the best outcomes remain unanswered. In this paper we summarize the current management of CPC in the literature. Further studies are needed to standardize the treatment paradigm for this malignant brain tumor.

Cribriform neuroepithelial tumor arising in the lateral ventricle

Cribriform neuroepithelial tumor (CRINET) is a recently recognized central nervous system neoplasm that arises in the ventricles of young children and is characterized by primitive, non-rhabdoid SMARCB1-deficient cells with prominent cribriform architecture. We report a 14-month-old male who presented with signs of increased intracranial pressure. Neuroimaging revealed a large solid and cystic mass in the lateral ventricle. Tumor cells were small, primitive appearing, and arranged in cribriform and trabecular patterns with interspersed solid cellular areas. Rhabdoid cells were absent. Immunohistochemical staining showed no SMARCB1 (INI11, BAF47, hSNF5) expression and strong epithelial membrane antigen (EMA) immunoreactivity along luminal surfaces. Electron microscopy showed epithelial characteristics, including abundant basal lamina. Genetic analysis of the tumor revealed deletion of 1 SMARCB1 allele, while the other contained an intronic point mutation predicted to disrupt splicing. This case further illustrates the distinct histopathologic and molecular genetic features of CRINET and identifies distinctive ultrastructural features.

Neuropathology of brain metastases

Metastatic tumors are the most common neoplasms encountered in the central nervous system (CNS), and continue to be major cause for mortality and morbidity. Macroscopic features and corresponding radiological findings can be diagnostic in majority of the cases, however, microscopic evaluation would be necessary when the differential diagnosis includes a primary CNS tumor, unknown primary tumor site, and when the resection of the tumor is either considered therapeutic or palliative. The first step in the diagnosis of a metastatic brain lesion is to exclude a primary CNS tumor, followed by verification or identification of the primary tumor and the site. Although general approach to a metastatic lesion from an unknown primary tumor is the same everywhere else, there are slight variations for the metastatic lesions in the CNS versus other regions. When morphological features are not enough to establish a definitive diagnosis, additional studies including immunohistochemical stains are applied. With the expending immunohistochemical armamentarium for pathologists, more accurate assessments are possible even in cases of unknown primary tumor. This review summarizes the diagnostic approach to CNS metastases, immunohistochemical assessment of neoplasm of unknown primary, and primary CNS lesions entering in the differential diagnosis of metastases.

Surgical outcomes in choroid plexus papillomas: an institutional experience

Choroid plexus papillomas (CPPs) are rare, indolent lesions that comprise less than 0.5 % of intracranial tumors. We sought to assess the long-term outcomes and associated surgical complications at our institution. A review of the University of California, San Francisco (UCSF) Brain Tumor Research Center (BTRC) database was performed to identify a cohort of patients treated for CPP from 1997 to 2011. Patients were grouped based on tumor location and extent of resection. Outcomes including progression-free survival and surgical complications were assessed. We identified 24 patients (16 female, 8 male) ranging in age from 6 months to 55 years (median 29 years) treated at our institution. Tumors were found in the following locations: 16 (67 %) fourth ventricle/cerebellopontine angle; 7 (29 %) lateral ventricle; 1 (4 %) third ventricle. Gross total resection (GTR) was achieved in 20 patients (83 %) with subtotal resection (STR) in 4 (17 %). Median follow-up time was 2.8 years with 3 recurrences identified at 1.6, 3.3, and 8.5 years. Extent of resection and tumor location were not associated with recurrence. There was one new permanent neurologic deficit detected after surgery. All patients were alive at most recent follow-up. Attempted gross total resection is the standard treatment for CPPs and generally associated with excellent outcomes. Since recurrences are rare, even among patients who undergo STR, radiation may be reserved for cases of tumor progression. This modern experience at a tertiary care center performed exclusively during the MRI-era demonstrates that CPPs can be safely removed with minimal morbidity and good tumor control.

Choroid plexus tumors: A clinico-pathological and neuro-radiological study of 23 cases

BACKGROUND

Choroid plexus tumors are intraventricular tumors derived from choroid plexus epithelium.

AIM

To study the choroid plexus tumors with reference to their clinical, radiological, and pathological features.

MATERIALS AND METHODS

The study was performed by the retrospectively reviewing the clinical, radiological, and pathological records of patients of choroid plexus tumors.

RESULTS

A total of 23 cases (11 males, 13 females) of choroid plexus tumor were diagnosed from 1997 to 2009. Fourteen patients were below 15 years of age. Raised intracranial pressure was the main presenting feature in all the cases. Tumor was located in lateral ventricle (n = 14; in 3 cases tumor was going into third ventricle), fourth ventricle (n = 7), and cerebellopontine angle (n = 2). Total tumor excision was achieved in 21 cases. The histopathology was suggestive of choroid plexus papilloma (n = 19), atypical choroid plexus papilloma (n = 1), and choroid plexus carcinoma (n = 2). Clears cell areas were noted in three cases. Other histopathological features observed were foci of calcification (n = 5), Psammoma bodies (n = 2), hemorrhage (n = 5), hyalinization (n = 2), and oncocytic changes (n = 1).

CONCLUSIONS

Choroid plexus tumors are intraventricular tumors arising from choroid plexus epithelium. The predominant clinical presentation is raised intracranial pressure. Surgery is the mainstay of treatment; histopathologically, they include choroid plexus papilloma, atypical choroid plexus papilloma, and choroid plexus carcinoma.

Choroid plexus papillomas: advances in molecular biology and understanding of tumorigenesis

Choroid plexus papillomas are rare, benign tumors originating from the choroid plexus. Although generally found within the ventricular system, they can arise ectopically in the brain parenchyma or disseminate throughout the neuraxis. We sought to review recent advances in our understanding of the molecular biology and oncogenic pathways associated with this disease. A comprehensive PubMed literature review was conducted to identify manuscripts discussing the clinical, molecular, and genetic features of choroid plexus papillomas. Articles concerning diagnosis, treatment, and long-term patient outcomes were also reviewed. The introduction of atypical choroid plexus papilloma as a distinct entity has increased the need for accurate histopathologic diagnosis. Advances in immunohistochemical staining have improved our ability to differentiate choroid plexus papillomas from other intracranial tumors or metastatic lesions using combinations of key markers and mitotic indices. Recent findings have implicated Notch3 signaling, the transcription factor TWIST1, platelet-derived growth factor receptor, and the tumor necrosis factor-related apoptosis-inducing ligand pathway in choroid plexus papilloma tumorigenesis. A combination of commonly occurring chromosomal duplications and deletions has also been identified. Surgical resection remains the standard of care, although chemotherapy and radiotherapy may be considered for recurrent or metastatic lesions. While generally considered benign, these tumors possess a complex biology that sheds insight into other choroid plexus tumors, particularly malignant choroid plexus carcinomas. Improving our understanding of the molecular biology, genetics, and oncogenic pathways associated with this tumor will allow for the development of targeted therapies and improved outcomes for patients with this disease.

Loss of TP53 expression in immortalized choroid plexus epithelial cells results in increased resistance to anticancer agents

Choroid plexus carcinomas are malignant brain tumors predominantly arising in young children. Because a prognostic role of p53 alterations has been demonstrated, further research into potential underlying mechanisms is essential. Our objective was, therefore, to investigate the role of p53 in the growth-inhibitory potential of a variety of anticancer agents in the rodent choroid plexus epithelial cell line Z310. Furthermore, association of p53 alterations with proliferative activity (Ki67/MIB1) in choroid plexus carcinoma samples (N = 20) was examined by use of immunohistochemistry. Silencing of TP53 expression did not significantly alter metabolic activity in Z310 cells and p53 protein expression status was not associated with increased proliferative activity in choroid plexus carcinomas. However, the growth-inhibitory activity of vincristine, doxorubicin, carboplatin, etoposide, and temozolomide was significantly impaired by silencing of TP53. In conclusion, these results indicate a potential predictive role of p53 in choroid plexus carcinomas. Alterations of p53 should be taken into account when evaluating the effect of anticancer agents in future clinical trials.

Diagnostic value of EAAT-1 and Kir7.1 for distinguishing endolymphatic sac tumors from choroid plexus tumors

The endolymphatic sac tumor (ELST) is a low-grade carcinoma originating in the ear. These extremely rare tumors are capable of invading the cerebellopontine angle and might be mistaken for choroid plexus tumors (CPTs) in this region. Currently, these tumors are distinguished by conventional morphologic and immunohistochemical studies for S-100, cytokeratin, and GFAP expression, but all markers are variably expressed by both tumors. Therefore, we examined new promising markers such as EAAT-1 and Kir7.1 in 4 ELSTs and 35 CPTs located in the fourth ventricle or at the cerebellopontine angle in adults. Immunohistochemical expression of Kir7.1 was found in 30 (100%) of 30 and EAAT-1 in 32 (91%) of 35 CPTs tested and was absent in all ELSTs. Expression of GFAP was found in 16 (55%) and S-100 in 29 (100%) of 29 CPTs tested, but both markers were also expressed in 2 of 4 ELSTs examined. Specificity and sensitivity of Kir7.1 (both 100%) and EAAT-1 (100% and 91%, respectively) were superior to the values for S-100 (50% and 100%, respectively) and GFAP (50% and 55%, respectively) for distinguishing CPT from ELST.

Molecular characterization of circumventricular organs and third ventricle ependyma in the rat: potential markers for periventricular tumors

Circumventricular organs (CVOs) are specialized ventricular structures around the third and fourth ventricles of the brain. In humans, these structures are present during the fetal period and some become vestigial after birth. Some of these organs, such as the pineal gland (PG), subcommissural organ (SCO), and organum vasculosum of the lamina terminalis, might be the sites of origin of periventricular tumors, notably pineal parenchymal tumors, papillary tumor of the pineal region and chordoid glioma. In contrast to the situation in humans, CVOs are present in the adult rat and can be dissected by laser capture microdissection (LCM). In this study, we used LCM and microarrays to analyze the transcriptomes of three CVOs, the SCO, the subfornical organ (SFO), and the PG and the third ventricle ependyma in the adult rat, in order to better characterize these organs at the molecular level. Several genes were expressed only, or mainly, in one of these structures, for example, Erbb2 and Col11a1 in the ependyma, Epcam and Claudin-3 (CLDN3) in the SCO, Ren1 and Slc22a3 in the SFO and Tph, Aanat and Asmt in the PG. The expression of these genes in periventricular tumors should be examined as evidence for a possible origin from the CVOs. Furthermore, we performed an immunohistochemical study of CLDN3, a membrane protein involved in forming cellular tight junctions and found that CLDN3 expression was restricted to the apical pole of ependymocytes in the SCO. This microarray study provides new evidence regarding the possible origin of some rare periventricular tumors.

Plastin family of actin-bundling proteins: its functions in leukocytes, neurons, intestines, and cancer

Sophisticated regulation of the actin cytoskeleton by a variety of actin-binding proteins is essential for eukaryotic cells to perform their diverse functions. The plastin (also know, as fimbrin) protein family belongs to actin-bundling proteins, and the protein family is evolutionarily conserved and expressed in yeast, plant, and animal cells. Plastins are characterized by EF-hand Ca²⁺-binding domains and actin-binding domains and can cross-link actin filaments into higher-order assemblies like bundles. Three isoforms have been identified in mammals. T-plastin is expressed in cells from solid tissues, such as neurons in the brain. I-plastin expression is restricted to intestine and kidney; the isoform plays a vital role in the function of absorptive epithelia in these organs. L-plastin is expressed in hematopoietic cell lineages and in many types of cancer cells; the isoform is thus considered to be a useful biomarker for cancer.

A rare case of papillary carcinoma of choroids plexus: Its management and review of literature

Papillary carcinoma of choroids plexus is very rare. Only a few cases have been described in the literature, and it is most commonly found in the pediatric population. A further observation is added now. A 20-year-old lady presented with complaints of headache and vomiting from past one and half months, headache was increasing in severity and there was relief after vomiting. On examination, no abnormality was detected in any of her systems. The patient underwent computed tomography scan of brain, which showed space occupying lesion in the right frontal lobe. She underwent near total excision of the lesion. Postoperative period was uneventful. Histopathology was suggestive of papillary carcinoma of choroids plexus and was confirmed with immunohistochemistry. The patient received whole brain radiation and intrathecal chemotherapy. The patient tolerated the treatment well, except for grade two vomiting. She has completed one and half years of follow-up and is disease free.

[Pathological aspects of the tumors of the lateral ventricles]

Typing a tumor of the lateral ventricle is often an issue, even for an experienced Neuropathologist. In this location are encountered specific entities, such as neurocytoma and subependymal giant cell astrocytoma, as well as more usual tumors, displaying a common misleading morphology, for instance a main clear cell component. The panel of diagnostic tools given to the pathologists has been increasing for a few years, enriched by immunohistochemical and molecular probes.

Choroid plexus papilloma originating from the cerebrum parenchyma

Background:

Choroid plexus papilloma (CPP) can develop at a primary intraparenchymal location completely unrelated to the ventricular system. Here, we present a case of CPP that was difficult to diagnose preoperatively.

Case Description:

Preoperative imaging and operative findings showed that the tumor originated entirely within the cerebrum parenchyma, with no connections between the tumor and the ventricular system. Histopathological examination of the tumor revealed a papillary structure with a single layer of well-differentiated columnar epithelium in the lesion. Furthermore, part of this lesion had infiltrated the cerebral parenchyma. Therefore, the tumor was diagnosed as CPP, and the diagnosis was confirmed by immunohistological examination.

Conclusions:

CPP originating as intraparenchymal growths are extremely rare. Origins of extraventricular CCP are discussed in the context of the literature.

A case of choroid plexus papilloma with stromal sclerosis and indistinct papillary structures

We present a case of choroid plexus papilloma with unusual histopathological findings. A 41-year-old Japanese man presented with dizziness. Brain magnetic resonance imaging scan showed a distinct mass in the fourth ventricle. Histopathological examination showed proliferation of cuboidal cells forming irregular trabeculae, small nests, and pseudoglandular and indistinct papillary structures, accompanied by a variable degree of stromal sclerosis. The tissue sections also showed rare mitotic activity, no hypercellularity, cellular pleomorphism, or necrosis. The immunohistochemical findings were tumor cells positive for cytokeratin 7, vimentin, S-100 protein, and transthyretin but negative for cytokeratin 20, BerEP4 and carcinoembryonic antigen. These findings were consistent with choroid plexus papilloma. The combination of these immunohistochemical markers was helpful in establishing the diagnosis, although the morphological finding of stromal sclerosis is rare for choroid plexus papilloma.

High expression of BMP pathway genes distinguishes a subset of atypical teratoid/rhabdoid tumors associated with shorter survival

Molecular profiling of tumors has proven to be a valuable tool for identification of prognostic and diagnostic subgroups in medulloblastomas, glioblastomas, and other cancers. However, the molecular landscape of atypical teratoid/rhabdoid tumors (AT/RTs) remains largely unexplored. To address this issue, we used microarrays to measure the gene expression profiles of 18 AT/RTs and performed unsupervised hierarchical clustering to determine molecularly similar subgroups. Four major subgroups (clusters) were identified. These did not conform to sex, tumor location, or presence of monosomy 22. Clusters showed distinct gene signatures and differences in enriched biological processes, including elevated expression of some genes associated with choroid plexus lineage in cluster 4. In addition, survival differed significantly by cluster, with shortest survival (mean, 4.7 months) in both clusters 3 and 4, compared with clusters 1 and 2 (mean, 28.1 months). Analysis showed that multiple bone morphogenetic protein (BMP) pathway genes were upregulated in the short survival clusters, with BMP4 showing the most significant upregulation (270-fold). Thus, high expression of BMP pathway genes was negatively associated with survival in this dataset. Our study indicates that molecular subgroups exist in AT/RTs and that molecular profiling of these comparatively rare tumors may be of diagnostic, prognostic, and therapeutic value.

Synchronous Choroid Plexus Papilloma of the Fourth Ventricle and Ependymoma of the Filum Terminale: Case Report

BACKGROUND AND IMPORTANCE:

We report the first case of synchronous choroid plexus papilloma of the fourth ventricle and myxopapillary ependymoma of the filum terminale. Both are papillary World Health Organization grade I tumors known to disseminate via cerebrospinal fluid pathways.

CLINICAL PRESENTATION:

A 65-year-old man presented with an incidental mass in the fourth ventricle found on a computed tomography scan of the head after a motor vehicle collision and an intradural mass of the filum terminale. The patient underwent resection of the fourth ventricle mass. After pathological diagnosis of a choroid plexus papilloma, the patient underwent resection of the spinal cord tumor.

CONCLUSION:

This case underscores the need for separate pathological diagnosis in a patient with an intradural spine lesion in the context of a benign intracranial lesion. We detail a panel of immunohistochemical markers essential for distinguishing the 2 papillary neuroectodermal tumors recovered in this case.

Intramedullary papillary ependymoma with choroid plexus differentiation and cerebrospinal fluid dissemination to the brain

This 8-year-old girl presented with a papillary ependymoma in the thoracic spinal cord. Resection was followed by recurrence at the primary site and later in the lumbosacral thecal sac, followed by cerebrospinal fluid dissemination to the brain approximately 5 years after her initial presentation. The tumor showed cytological and immunohistochemical features overlapping those of classic ependymomas and choroid plexus tumors similar to those seen in uncommon supratentorial papillary ependymomas, also known as papillary tumors of the pineal region. The histopathological and clinical courses of this rare spinal papillary ependymoma exhibiting mixed ependymal and choroid plexus-like differentiation are discussed.

Inwardly rectifying potassium channels: their structure, function, and physiological roles

Inwardly rectifying K(+) (Kir) channels allow K(+) to move more easily into rather than out of the cell. They have diverse physiological functions depending on their type and their location. There are seven Kir channel subfamilies that can be classified into four functional groups: classical Kir channels (Kir2.x) are constitutively active, G protein-gated Kir channels (Kir3.x) are regulated by G protein-coupled receptors, ATP-sensitive K(+) channels (Kir6.x) are tightly linked to cellular metabolism, and K(+) transport channels (Kir1.x, Kir4.x, Kir5.x, and Kir7.x). Inward rectification results from pore block by intracellular substances such as Mg(2+) and polyamines. Kir channel activity can be modulated by ions, phospholipids, and binding proteins. The basic building block of a Kir channel is made up of two transmembrane helices with cytoplasmic NH(2) and COOH termini and an extracellular loop which folds back to form the pore-lining ion selectivity filter. In vivo, functional Kir channels are composed of four such subunits which are either homo- or heterotetramers. Gene targeting and genetic analysis have linked Kir channel dysfunction to diverse pathologies. The crystal structure of different Kir channels is opening the way to understanding the structure-function relationships of this simple but diverse ion channel family.

Choroid plexus: biology and pathology

The choroid plexus is an epithelial-endothelial vascular convolute within the ventricular system of the vertebrate brain. It consists of epithelial cells, fenestrated blood vessels, and the stroma, dependent on various physiological or pathological conditions, which may contain fibroblasts, mast cells, macrophages, granulocytes or other infiltrates, and a rich extracellular matrix. The choroid plexus is mainly involved in the production of cerebrospinal fluid (CSF) by using the free access to the blood compartment of the leaky vessels. In order to separate blood and CSF compartments, choroid plexus epithelial cells and tanycytes of circumventricular organs constitute the blood-CSF-brain barrier. As non-neuronal cells in the brain and derived from neuroectoderm, choroid plexus epithelia are defined as a subtype of macroglia. The choroid plexus is involved in a variety of neurological disorders, including neurodegenerative, inflammatory, infectious, traumatic, neoplastic, and systemic diseases. Abeta and Biondi ring tangles accumulate in the Alzheimer's disease choroid plexus. In multiple sclerosis, the choroid plexus could represent a site for lymphocyte entry in the CSF and brain, and for presentation of antigens. Recent studies have provided new diagnostic markers and potential molecular targets for choroid plexus papilloma and carcinoma, which represent the most common brain tumors in the first year of life. We here revive some of the classical studies and review recent insight into the biology and pathology of the choroid plexus.

Malignant Transformation in Mature Cystic Teratoma of the Ovary

This study reports 3 unusual cases of malignant transformation in mature cystic teratoma of the ovary (dermoid cyst), namely carcinosarcoma, atypical choroid plexus papilloma, and papillary thyroid carcinoma, the last case involving both ovaries and with peritoneal dissemination. Adequate sampling is essential in such ovarian tumors to establish their teratomatous origin and avoid an erroneous diagnosis of primary ovarian or metastatic tumors. The authors present the clinicopathological findings in these 3 cases with a review of literature.

Atypical choroid plexus papilloma: clinical experience in the CPT-SIOP-2000 study

Atypical choroid plexus papilloma (APP) represents a novel intermediate-grade subtype of choroid plexus tumor (CPT), the clinical outcome of which has not been described yet. We present the first analysis of a group of APP patients enrolled in the ongoing CPT-SIOP-2000 study of CPTs. A worldwide registration and a randomized trial for those patients who require chemotherapy started in 2000. For APP, maximal surgical resection was recommended. After surgery, patients who had undergone complete resection were observed, whereas patients with incompletely resected or metastasized APP were treated with six chemotherapy courses (etoposide and vincristine, combined with either carboplatin or cyclophosphamide). Risk-adapted radiotherapy was given only to patients older than 3 years of age. Of the 106 patients with a centrally confirmed CPT histology, 30 had APP, 42 CPP and 34 CPC. APP patients were significantly younger (median = 0.7 years) than patients with CPP or CPC (both medians = 2.3 years). Complete resection was achieved in 68 (64%) patients (79% in CPP, 63% in APP, and 47% in CPC). Metastases were present at diagnosis in 17% of APP patients, 5% of CPP patients, and 21% of CPC patients. All nine APP patients who received postoperative chemotherapy showed an early response after two cycles: two had complete remission, four had partial response, and three had stable disease. In the observation group of 15 patients, one event was seen, and all patients were alive. In the treatment group, one patient with a metastasized tumor and incompletely resected APP died. While APP was defined histologically, median percentages of both the Ki-67/MIB-1 proliferation marker and the p53 tumor suppressor protein increased across the three histological subtypes (from CPP to APP and then CPC), suggesting that the subtypes comprise an ordinal categorization of increasingly severe CPT tumors. This ordering was reiterated by clinical outcome in the 92 patients treated per the study protocol, with 5-year EFS rates of 92% in 39 CPP patients, 83% in 24 APP patients, and 28% in 29 CPC patients. A similar ordering was seen when all 106 patients were evaluated for EFS. APP responded favorably to chemotherapy. The intermediate position of APP between CPP and CPC was supported by the clinical data.