Malignant progression in choroid plexus papillomas

Primary adult choroid plexus carcinomas: a single-center experience with a systematic review

Objective

Primary adult choroid plexus carcinomas (PACPCs) are extremely rare brain tumors. The existing literature primarily comprises case reports, which limits our understanding of this uncommon disease. This study aims to describe the clinical characteristics and prognosis of PACPCs, as well as to identify optimal treatment strategies.

Methods

We conducted a comprehensive analysis of clinical data from 7 patients with PACPCs who underwent surgical treatment at the Department of Neurosurgery, Beijing Tiantan Hospital, between March 2011 and March 2023. Additionally, a thorough search of the PubMed database was performed using the keywords "choroid plexus carcinoma" or "choroid plexus carcinomas" within the time frame of August 1975 to April 2023, which yielded a total of 28 identified cases. Subsequently, we evaluated risk factors for progression-free survival (PFS) and overall survival (OS) based on the pooled cases.

Results

The pooled cohort, consisting of 7 cases from our institution and 28 cases from the literature, included 20 males and 15 females with a mean age of 44.3 ± 14.7 years (range: 21-73 years). Gross-total resection (GTR) and non-GTR were achieved in 22 (62.9%) and 13 (37.1%) patients, respectively. Radiotherapy and chemotherapy were administered to 29 (90.6%) and 13 (40.6%) patients, respectively. After a mean follow-up of 21.0 ± 26.7 months (range: 2-132 months), 18 patients were alive, and 11 patients had died. The multivariate Cox regression model demonstrated that non-GTR (HR 5.262, 95% CI 1.350-20.516, p=0.017) was a negative prognostic factor for OS. However, we did not find any risk factors for PFS.

Conclusion

Complete surgical resection should be considered as the primary treatment approach for this rare disease. Chemotherapy and radiotherapy appear to have limited effectiveness in treating this condition. Further research with large cohorts is needed to validate our conclusions.

Intracranial Choroid Plexus Carcinomas: Report of 11 Cases from a Single Institution

BACKGROUND

Choroid plexus carcinoma is a central nervous system tumor pathologically corresponding to World Health Organization grade III. Choroid plexus carcinoma mainly affects pediatric patients with a poor prognosis. Due to its rarity, standardized treatment has not yet been outlined.

METHODS

We retrospectively analyzed 11 patients with histopathologically diagnosed choroid plexus carcinoma between January 2008 and December 2016. They were treated with surgical resection with or without adjuvant therapies. The clinical profiles and outcomes were analyzed.

RESULTS

The mean age at diagnosis was 16.0 years (median, 7.0 years; range, 4 months to ∼59 years). Gross total resection was achieved in 9 cases, and subtotal resection in 2 cases. Seven patients received adjuvant radiotherapy, and 2 patients underwent chemotherapy. The mean overall survival was 34.8 months, and the mean progression-free survival was 24.5 months. During the follow-up period, 4 patients succumbed to central nervous system dissemination of choroid plexus carcinoma including 2 patients with malignant transformation from atypical choroid plexus papilloma to choroid plexus carcinoma and 1 patient treated with the combined chemotherapy protocol.

CONCLUSIONS

In this study, we described the clinicoradiologic characteristics of choroid plexus carcinomas. Surgical resection is the mainstream treatment. Due to the paucity of clinical evidence, the standard regimen of adjuvant therapies still needs further research.

Molecular insights into malignant progression of atypical choroid plexus papilloma

Choroid plexus tumors are rare pediatric neoplasms ranging from low-grade papillomas to overtly malignant carcinomas. They are commonly associated with Li–Fraumeni syndrome and germline TP53 mutations. Choroid plexus carcinomas associated with Li–Fraumeni syndrome are less responsive to chemotherapy, and there is a need to avoid radiation therapy leading to poorer outcomes and survival. Malignant progression from choroid plexus papillomas to carcinomas is exceedingly rare with only a handful of cases reported, and the molecular mechanisms of this progression remain elusive. We report a case of malignant transformation of choroid plexus papilloma to carcinoma in a 7-yr-old male with a germline TP53 mutation in which we present an analysis of molecular changes that might have led to the progression based on the next-generation genetic sequencing of both the original choroid plexus papilloma and the subsequent choroid plexus carcinoma. Chromosomal aneuploidy was significant in both lesions with mostly gains present in the papilloma and additional significant losses in the carcinoma. The chromosomal loss that occurred, in particular loss of Chromosome 13, resulted in the losses of two critical tumor suppressor genes, RB1 and BRCA2, which might play a possible role in the observed malignant transformation.

Endoplasmic Reticulum Calcium Pumps and Tumor Cell Differentiation

Endoplasmic reticulum (ER) calcium homeostasis plays an essential role in cellular calcium signaling, intra-ER protein chaperoning and maturation, as well as in the interaction of the ER with other organelles. Calcium is accumulated in the ER by sarco/endoplasmic reticulum calcium ATPases (SERCA enzymes) that generate by active, ATP-dependent transport, a several thousand-fold calcium ion concentration gradient between the cytosol (low nanomolar) and the ER lumen (high micromolar). SERCA enzymes are coded by three genes that by alternative splicing give rise to several isoforms, which can display isoform-specific calcium transport characteristics. SERCA expression levels and isoenzyme composition vary according to cell type, and this constitutes a mechanism whereby ER calcium homeostasis is adapted to the signaling and metabolic needs of the cell, depending on its phenotype, its state of activation and differentiation. As reviewed here, in several normal epithelial cell types including bronchial, mammary, gastric, colonic and choroid plexus epithelium, as well as in mature cells of hematopoietic origin such as pumps are simultaneously expressed, whereas in corresponding tumors and leukemias SERCA3 expression is selectively down-regulated. SERCA3 expression is restored during the pharmacologically induced differentiation of various cancer and leukemia cell types. SERCA3 is a useful marker for the study of cell differentiation, and the loss of SERCA3 expression constitutes a previously unrecognized example of the remodeling of calcium homeostasis in tumors.

Epigenetics impacts upon prognosis and clinical management of choroid plexus tumors

PURPOSE

Choroid plexus tumors comprise of choroid plexus papilloma (CPP, WHO grade I), atypical choroid plexus papilloma (aCPP, WHO grade II) and choroid plexus carcinoma (CPC, WHO grade III). Molecular events driving the majority of choroid plexus tumors remain poorly understood. Recently, DNA methylation profiling has revealed different epigenetic subgroups.

METHODS

Comprehensive review of epigenetic profiles of choroid plexus tumors in the context of histopathological, genetic, and clinical features. DNA methylation profiling segregates choroid plexus tumors into three distinct epigenetic subgroups: supratentorial pediatric low-risk choroid plexus tumors (CPP and aCPP), infratentorial adult low-risk choroid plexus tumors (CPP and aCPP), and supratentorial pediatric high-risk choroid plexus tumors (CPP and aCPP and CPC). Epigenetic subgrouping provides additional prognostic information in comparison to histopathological grading.

CONCLUSIONS

Epigenetic profiling of choroid plexus tumors can be used for the identification of patients at risk of recurrence and is expected to play a role for treatment stratification and patient management in the context of future clinical trials.

Myc and Loss of p53 Cooperate to Drive Formation of Choroid Plexus Carcinoma

Choroid plexus carcinoma (CPC) is a rare brain tumor that occurs most commonly in very young children and has a dismal prognosis despite intensive therapy. Improved outcomes for patients with CPC depend on a deeper understanding of the mechanisms underlying the disease. Here we developed transgenic models of CPCs by activating the Myc oncogene and deleting the Trp53 tumor suppressor gene in murine neural stem cells or progenitors. Murine CPC resembled their human counterparts at a histologic level, and like the hypodiploid subset of human CPC, exhibited multiple whole-chromosome losses, particularly of chromosomes 8, 12, and 19. Analysis of murine and human CPC gene expression profiles and copy number changes revealed altered expression of genes involved in cell cycle, DNA damage response, and cilium function. High-throughput drug screening identified small molecule inhibitors that decreased the viability of CPC. These models will be valuable tools for understanding the biology of choroid plexus tumors and for testing novel approaches to therapy. SIGNIFICANCE: This study describes new mouse models of choroid plexus carcinoma and uses them to investigate the biology and therapeutic responsiveness of this highly malignant pediatric brain tumor.

Nonvestibular Schwannoma Tumors in the Cerebellopontine Angle: A Single-Surgeon Experience

Background:

The most common cerebellopontine angle (CPA) tumor is a vestibular schwannoma. Schwannomas account for 8.5% of all intracranial tumors and more than 90% of the tumors originate from the eighth cranial nerve, but one in five CPA tumors are not vestibular schwannoma. These tumors may have different manifestations and require different management strategies.

Methods:

We report 224 consecutive NVCPAT operated in the Department of Neurosurgery, P.D. Hinduja National Hospital and Medical Research Centre, Mumbai, by the senior author between 2001 and 2014 and discuss the different approaches and outcomes in NVCPAT.

Results:

The age range was 20–60 years and there were 129 females and 95 male patients. The clinical material consisted of 81 cases of meningioma (36.1%), 44 cases of epidermoid (19.64%), 34 cases of trigeminal schwannoma (15.17%), 26 cases of jugular foramen schwannoma (11.60%), and 39 cases of other tumors (17.41%). In nonvestibular schwannoma (NVS), symptoms and signs from cranial nerve VIII are less frequent and other cranial nerves and cerebellar symptoms and signs predominate.

Conclusion:

Symptoms and signs are different in NVCPAT from those found in patients with vestibular schwannoma. Hearing loss is not the predominant symptoms. Cerebellar signs and trigeminal dysfunction are more common. The most common approach used in the current series was retrosigmoid craniotomy. Gamma knife radiosurgery was a useful adjunct in a subset of these patients.

Management of choroid plexus tumors-an institutional experience

Background

Choroid plexus tumors are rare entities. Resection is the mainstay of treatment in grade I and grade II tumors and adjuvant treatment is usually reserved for the less frequent choroid plexus carcinoma (CPC). Outcome is not only related to their histological grade but also dependent on their size, location, and presence of often multifactorial disturbances of cerebrospinal fluid (CSF) circulation.

Methods

Retrospective analysis of 36 consecutive patients operated on a choroid plexus tumor at our institution in a mixed pediatric and adult population between 1991 and 2016.

Results

Twenty-one CPP, 11 atypical choroid plexus papillomas (aCPP), and four CPC were encountered in 17 children and 19 adults. Regardless of histological grading, gross-total resection (GTR) could be achieved in 91.7% of patients. Tumor recurrence (25.0%) was significantly associated with histological grading (p = 0.004), subtotal resection (p = 0.002), and intraoperatively evident zones of tumor infiltration (p = 0.001). Adjuvant therapy was performed in 19.4% of patients, mainly diagnosed with CPC. The 5-year overall survival rate was 95.2% for CPP and 100.0% for both aCPP and CPC. Survival was related to the extent of resection (p = 0.001), tumor progression (p = 0.04), and the presence of leptomeningeal metastases (p = 0.002). Even after resection, either ventricular or subdural shunting was required in 25.0% of patients.

Conclusions

We could confirm that GTR is crucial for treatment of choroid plexus tumors. Parenchymal tumor infiltration as detected intraoperatively was associated with the extent of resection and not limited to CPC. CSF disturbances mandating treatment may persist after resection.

Clinical Features and Prognostic Risk Factors of Choroid Plexus Tumors in Children

Background:

Decision-making concerning the treatment of choroid plexus tumor (CPT) in pediatric patients remains a topic of considerable debate. The aim of this work was to describe clinical features and prognostic risk factors of CPT in the pediatric population and to provide theoretical opinions regarding clinical decisions for CPT.

Methods:

The data of 96 patients with CPT and younger than 14 years were retrospectively analyzed. Clinical characteristics such as pathological type of CPTs, rate and severity of hydrocephalus, treatment and outcome, and recurrence were investigated. For categorical variables, the Pearson's Chi-square test was performed. The Mann–Whitney U-test was used for comparisons between nonnormally distributed parameters. Log-rank test was used for progression-free survival (PFS).

Results:

The study included 70 choroid plexus papilloma (CPP) cases, 17 atypical choroid plexus papilloma (aCPP) cases, and 9 choroid plexus carcinoma (CPC) cases. Compared with patients with CPP or aCPP, patients with CPC had a shorter disease course (median: CPP, 4 months; aCPP, 2 months; CPC, 1 month; H: 23.5, P < 0.001), higher rate of acute hydrocephalus (CPP, 27.1%; aCPP, 52.9%; CPC, 77.8%; χ² = 10.9, P < 0.05), and lower incidence of cure rate (CPP, 85.7%; aCPP, 70.5%; CPC, 33.3%; χ² = 13.5, P < 0.05). The severity of hydrocephalus with tumor in the lateral or third ventricle was significantly higher than that with tumors in the fourth ventricle (severe hydrocephalus: lateral ventricle, 51.7%; third ventricle, 47.0%; fourth ventricle, 11.1%; χ² = 26.0, P < 0.001). Patients with gross total surgical resection had no better PFS than those with partial resection because of the use of adjuvant therapy in the latter (χ² = 4.0, P > 0.05). Patients with CPC experienced shorter time for recurrence than those with CPP or aCPP (χ² = 40.1, P < 0.0001).

Conclusions:

Our results indicated that CPP in the fourth ventricle could trigger serious clinical symptoms at an early stage, requiring early intervention. Adjuvant treatment might be necessary for patients with partially resected CPP, aCPP, and CPC to achieve a favorable outcome.

Rapid malignant progression of an intraparenchymal choroid plexus papillomas

Background:

Choroid plexus tumors (CPTs) are rare neoplasms accounting for only 0.3–0.6% of all brain tumors in adults and 2–5% in children. The World Health Organization (WHO) classification describes three histological grades: grade I is choroid plexus papilloma (CPP), grade II is atypical papilloma, and grade III is the malignant form of carcinoma. In adults, CPTs rarely have a supratentorial localization.

Case Description:

Here we report a very rare case of an intraparenchymal parietal CPP with a rapid histological transition from grade I to grade III WHO in a 67-year-old man, in <7 months.

Conclusion:

Because of the rarity of these oncotypes, descriptions of each new case are useful, mostly to consider this diagnostic entity in extraventricular brain tumors of adults, despite an unusual location.

Choroid Plexus Papillomas of the Cerebellopontine Angle

OBJECTIVE

Choroid plexus papillomas (CPPs) of the cerebellopontine angle (CPA) are extremely rare. We present a series of 21 cases operated on in the last 7 years at our institution.

METHODS

During the period from January 2008 to October 2015, we encountered 102 histologically established cases of CPPs, of which 21 were located in the CPA region. Clinical profiles, radiologic features, surgical procedures, intraoperative findings, and outcomes were extracted from the patient records and neuroimaging data.

RESULTS

The 21 CPPs in the CPA region accounted for 20.5% of all CPPs. Two of the tumors occurred in pediatric patients. Tumor size was 2.5-4.7 cm. The rate of calcification was higher in the CPPs in the CPA region. Peritumoral cysts and cysts with small nodules were observed in our cases. A far lateral suboccipital approach was chosen for CPPs protruding inferiorly into the foramen magnum region (n = 14), and a suboccipital retrosigmoid approach was chosen for the other tumors. Total resection was achieved in 18 patients, and subtotal resection was achieved in 3 patients. During the follow-up period, only 1 patient experienced recurrence 32 months after the first operation. The recurrence turned out to be an atypical CPP.

CONCLUSIONS

CPPs in the CPA region cannot be easily differentiated from other tumors preoperatively. Cysts and calcifications appear on neuroimaging. CPPs in the CPA region usually protrude inferiorly into the foramen magnum region. As much tumor should be removed as possible to avoid recurrence and malignant transition.

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.

The choroid plexus: a comprehensive review of its history, anatomy, function, histology, embryology, and surgical considerations

INTRODUCTION

The role of the choroid plexus in cerebrospinal fluid production has been identified for more than a century. Over the years, more intensive studies of this structure has lead to a better understanding of the functions, including brain immunity, protection, absorption, and many others. Here, we review the macro- and microanatomical structure of the choroid plexus in addition to its function and embryology.

METHOD

The literature was searched for articles and textbooks for data related to the history, anatomy, physiology, histology, embryology, potential functions, and surgical implications of the choroid plexus. All were gathered and summarized comprehensively.

CONCLUSION

We summarize the literature regarding the choroid plexus and its surgical implications.

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.

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.

Choroid plexus carcinoma in an adult

Choroid plexus carcinoma is a very rare tumor in adults. Here we report a rare case of choroid plexus carcinoma in an adult patient. A 24-year-old male presented with a right temporal intraventricular tumor with a cystic component also extending up to the cortex. Histological examination revealed complex papillary structures and glandular spaces showing stratification and multilayering of cells with nuclear crowding and numerous mitotic figures and large areas of necrosis. The patient went through a complete search for a possible primary keeping in mind the differential diagnosis of metastatic carcinoma that is more common in adults but there was no evidence of any other tumor. Finally a diagnosis of choroid plexus carcinoma was rendered. Immunohistochemical analysis for p53 protein showed positivity. Choroid plexus carcinoma is exceptionally rare in adults but cases do occur.

Atypical transformation in sacral drop metastasis from posterior fossa choroid plexus papilloma

Choroid plexus papillomas (CPP) are rare tumours and spinal metastases of CPP are even less common. We report a 50-year-old woman with spinal drop metastases at Th9 and S1-2 6 years after total resection of a posterior fossa CPP. The metastasis at S1-2 was resected and histological examination showed transformation to an atypical CPP. Atypical transformation in a metastasis years after resection of a benign posterior fossa CPP has been described once. We would like to advocate craniospinal MRI at the time of initial diagnosis as well as periodic follow-up after total and subtotal resection of a posterior fossa CPP in adults at least once in 1 or 2 years, depending on the histological grading of the primary CPP. In our case report, this could have resulted in earlier diagnosis of the locoregional recurrence or of the spinal drop metastasis.

Recurrence of fourth ventricular choroid plexus papilloma with late occurrence of a spinal drop metastasis

Choroid plexus papillomas are rare tumours, which occasionally spread both intracranially and down the spinal canal. Spinal metastasis has been reported infrequently and only once many years since the initial diagnosis. This is the first reported case of late recurrence, metastasis and transformation of a benign to an atypical lesion.

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.

Atypical choroid plexus papilloma in an adult

We present an extremely rare case of the atypical choroid plexus papilloma in an adult which developed at the trigone of right lateral ventricle. A 62-year-old woman presented with the history of intermittent and gradually progressive headache and left side hemiparesis for 6 months. The brain magnetic resonance image showed highly enhanced and well demarcated mass at the trigone of lateral ventricle attached to the choroid plexus. Gross total resection was performed by transcortical approach via the middle temporal gyrus. The tumor was diagnosed as an atypical choroid plexus papilloma. She had no neurologic deficit after the surgery. We report a case of atypical choroid plexus papilloma in adult and introduce newly classified pathologic characteristics of this tumor.

TWIST-1 is overexpressed in neoplastic choroid plexus epithelial cells and promotes proliferation and invasion

The pathogenesis of choroid plexus papillomas, intraventricular papillary neoplasms most often occurring sporadically in children and young adults, remains poorly understood. To identify pathways operative in the development of choroid plexus papillomas, gene expression profiles obtained from laser-microdissected human choroid plexus papilloma cells (n = 7) were compared with that of normal choroid plexus epithelial cells laser microdissected from autopsy tissue (n = 8). On DNA microarray data analysis, 53 probe sets were differentially expressed in choroid plexus papilloma tumor cells (>7-fold). Up-regulation of TWIST1, WIF1, TRPM3, BCLAF1, and AJAP1, as well as down-regulation of IL6ST was confirmed using quantitative reverse transcription-PCR. Knockdown of Twist1 gene expression in the rat choroid plexus epithelial cell line Z310 significantly reduced proliferation as assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and cell invasion in a Matrigel assay, whereas cell migration was not affected. Screening for expressional changes of cancer-related genes upon Twist1 knockdown revealed up-regulation of Cdkn1a, Cflar, and Serpinb2 and down-regulation of Figf. To conclude, using gene expression profiling, several genes differentially expressed in human choroid plexus papillomas could be identified. Among those, TWIST1 is highly expressed in choroid plexus papillomas and promotes proliferation and invasion.

Histone acetylation resulting in resistance to methotrexate in choroid plexus cells

Choroid plexus carcinomas are rare tumors that typically occur in young children. Prognosis is poor, and very little information is available to optimize treatment protocols. We used a cell culture model to evaluate whether combining chemotherapeutic agents such as methotrexate with histone deacetylase inhibitors (HDACI) such as valproic acid and MS-275 could improve efficacy. Valproic acid increased the cytotoxicity of radiation and of all the chemotherapeutic agents in Z310 and SV11 mouse choroid plexus cell lines, with the exception of methotrexate. Both HDACIs made choroid plexus cells resistant to this folate antagonist. Searching for a molecular explanation, we found that thymidylate synthase was up regulated when the cells were incubated with HDACI. We also confirmed this finding in human choroid plexus carcinoma cells. Methotrexate should not be combined with HDACI in the treatment of choroid plexus carcinoma.