Multi-omics analyses of choroid plexus carcinoma cell lines reveal potential targetable pathways and alterations.

PURPOSE: Choroid plexus carcinomas (CPCs) are extremely rare brain tumors and carry a dismal prognosis. Treatment options are limited and there is an urgent need to develop models to further research. In the present study, we established two CPC cell lines and performed multi-omics analyses. These cell lines serve as valuable models to propose new treatments in these rare but deadly brain tumors. METHODS: Multi-omic profiling including, (i) methylation array (EPIC 850 K), (ii) whole genome sequencing (WGS), (iii) CANCERPLEX cancer genome panel testing, (iv) RNA sequencing (RNA-seq), and (v) proteomics analyses were performed in CCHE-45 and NGT131 cell lines. RESULTS: Both cell lines were classified as methylation class B. Both harbored pathogenic TP53 point mutations; CCHE-45 additionally displayed TP53 loss. Furthermore, alterations of the NOTCH and WNT pathways were also detected in both cell lines. Two protein-coding gene fusions, BZW2-URGCP, and CTTNBP2-ERBB4, mutations of two oncodrivers, GBP-4 and KRTAP-12-2, and several copy number alterations were observed in CCHE-45, but not NGT131. Transcriptome and proteome analysis identified shared and unique signatures, suggesting that variability in choroid plexus carcinoma tumors may exist. The discovered difference's importance and implications highlight the possible diversity of choroid plexus carcinoma and call for additional research to fully understand disease pathogenesis. CONCLUSION: Multi-omics analyses revealed that the two choroid plexus carcinoma cell lines shared TP53 mutations and other common pathway alterations and activation of NOTCH and WNT pathways. Noticeable differences were also observed. These cell lines can serve as valuable models to propose new treatments in these rare but deadly brain tumors.

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.

Tumors of Choroid Plexus and Other Ventricular Tumors.

Tumors arising inside the ventricular system are rare but represent a difficult diagnostic and therapeutic challenge. They usually are diagnosed when reaching a big volume and tend to affect young children. There is a wide broad of differential diagnoses with significant variability in anatomical aspects and tumor type. Differential diagnosis in tumor type includes choroid plexus tumors (papillomas and carcinomas), ependymomas, subependymomas, subependymal giant cell astrocytomas (SEGAs), central neurocytomas, meningiomas, and metastases. Choroid plexus tumors, ependymomas of the posterior fossa, and SEGAs are more likely to appear in childhood, whereas subependymomas, central neurocytomas, intraventricular meningiomas, and metastases are more frequent in adults. This chapter is predominantly focused on choroid plexus tumors and radiological and histological differential diagnosis. Treatment is discussed in the light of the modern acquisition in genetics and epigenetics of brain tumors.

Paediatric choroid plexus carcinoma: a retrospective case series from Karachi.

The objective of this study is to report clinical, radiological, and histopathological characteristics of three paediatric patients diagnosed as Choroid plexus carcinoma seen at our hospital, between 2015 and 2020. Three patients were diagnosed with choroid plexus carcinomas between 2015 and 2018. The mean age at diagnosis was 1.3 years (range 8 months to 1.5 years). All the three patients had subtotal resection and received adjuvant chemotherapy. One patient also received adjuvant radiotherapy. Despite these treatment measures, residual disease was noted in all three patients and two patients were subsequently treated on palliative care grounds. The average duration of follow-up after the first surgery for all three patients was approximately 33 months. Attaining satisfactory outcome in patients with CPC is challenging. Our case series reflects the difficulty in achieving gross total resection and ensuring that the disease does not recur.

Case Report : Li-Fraumeni Syndrome with Central Nervous System Tumors in Two Siblings.

BACKGROUND: Li-Fraumeni syndrome (LFS) is a rare autosomal dominant cancer predisposition syndrome caused by germline TP53 gene mutations. It is characterized by high risk of early-onset cancer, and has been confirmed as associated with multiple tumors clinically. So pediatricians should be more alert to LFS in children with tumors. Choroid plexus carcinoma (CPC) is a rare, malignant tumor which account for less than 1% of all central nervous system (CNS) tumors. However, when such tumorigenesis occurs, it is important to be vigilant for the presence of LFS. CASE PRESENTATION: The first patient is a 32-month-old boy admitted for convulsions and then was found intracranial space-occupying lesion. Underwent operation, he was diagnosis as choroid plexus carcinoma (WHO Grade III). After 5 months, his elder sister, a 13-year-old girl, was brought to emergency department for confusion and intermittent convulsions. Surgery was performed immediately after head CT examination found the lesion. The pathology result indicated glioblastoma. Because the siblings of the same family have successively suffered from malignant tumors, we performed genetic testing on this family. TP53 gene mutation occurred in both children of these two cases from their father, and their other brother was not spared either. So the two siblings both met the diagnostic criteria of LFS. Then they all received systematic anti-tumor therapy, and follow-up hitherto. CONCLUSION: Here we reported a rare LFS case that two siblings were inherited the same TP53 germline mutations from their father. They suffered from choroid plexus carcinoma and glioblastoma and were finally diagnosed with LFS. In this LFS family, the primary tumors of the two children were both central nervous system tumors, which were not reported in the previous literature. It is suggested that clinicians should be alert to LFS related tumors, which is helpful for early diagnosis. Timely detection of TP53 gene is an important way for early diagnosis of LFS, especially in children with tumor. The incidence of secondary tumor in LFS patients is significantly higher, and other family members of the LFS patient also have an increased risk of suffering from the tumors. Therefore, early diagnosis and timely tumor surveillance can obtain better therapeutic effect and prognosis for both proband and their family.

An update on the central nervous system manifestations of Li-Fraumeni syndrome.

Li-Fraumeni syndrome (LFS), caused by the germline mutations in the TP53 gene, leads to significant lifetime risk to cancer in the central nervous system. Recognition of LFS, and elucidating its underlying cause has had a remarkable effect on our knowledge of the biology of brain tumors and represents a significant opportunity for cancer surveillance and screening. In this review, we discuss the historical context of the LFS with an emphasis on the clinicopathologic implications in clincal diagnosis, germline testing, and clinical management of brain tumor patients.

Intraventricular choroid plexus tumors: clinical characteristics and impact of current management on survival.

INTRODUCTION: Choroid plexus tumors (CPTs) represent one of the most common intraventricular tumors. Although most are benign, they often reach considerable sizes before clinical manifestation, challenging their surgical management. We aim to describe the clinical characteristics and the impact of current management on the survival of patients harboring intraventricular CPT. METHODS: The National Cancer Database (NCDB) was queried to identify biopsy-proven intraventricular CPT patients (2004-2015). Demographic and patterns of care were described, the log-rank method was used to independently analyze survival according to age, WHO grade and extent of resection (EOR). Multivariate analysis was performed to investigate the impact of prognostic factors on overall survival (OS). RESULTS: A total of 439 CPT patients with known WHO grade were included. WHO grade I tumors were more frequent in adults, while WHO grade III tumors were more common in pediatric population. Most CPTs were benign, with a median tumor size of 3-4 cm. Mean tumor size in pediatric population was greater than in adult population (4.39 cm vs. 2.7 cm; p < 0.01). Frequency was similar between males and females (51.7% vs. 48.3%; p > 0.0.5). Five- and ten-year OS among all patients was 87% and 84%, respectively. EOR was not associated with survival for any WHO grade. On multivariable analysis, only patient age (p = 0.022), WHO grade (p = 0.003) and medical comorbidity scores (p = 0.002) were independently associated with OS after diagnosis. CONCLUSION: Patients with CPTs present at different stages of life, with sizable tumor burden and distinct WHO grade prevalence. Considering their favorable survival, efforts to improve tumor control should be meticulously weighed against the long-term risk associated with surgery, radiation, and chemotherapy.

Structure-based design generated novel hydroxamic acid based preferential HDAC6 lead inhibitor with on-target cytotoxic activity against primary choroid plexus carcinoma.

Histone deacetylase 6 (HDAC6) is an attractive target for cancer therapeutic intervention. Selective HDAC6 inhibitors is important to minimise the side effects of pan inhibition. Thus, new class of hydroxamic acid-based derivatives were designed on structural basis to perform preferential activity against HDAC6 targeting solid tumours. Interestingly, 1-benzylbenzimidazole-2-thio-N-hydroxybutanamide 10a showed impressive preference with submicromolar potency against HDAC6 (IC50 = 510 nM). 10a showed cytotoxic activity with interesting profile against CCHE-45 at (IC50 = 112.76 µM) when compared to standard inhibitor Tubacin (IC50 = 20 µM). Western blot analysis of acetylated-α-tubulin verified the HDAC6 inhibiting activity of 10a. Moreover, the insignificant difference in acetylated-α-tubulin induced by 10a and Tubacin implied the on-target cytotoxic activity of 10a. Docking of 10a in the binding site of HDAC6 attributed the activity of 10a to π-π stacking with the amino acids of the hydrophobic channel of HDAC6 and capture of zinc metal in bidentate fashion. The therapeutic usefulness besides the on-target activity may define 10a as an interesting safe-lead inhibitor for future development.

Perinatal (fetal and neonatal) choroid plexus tumors: a review.

INTRODUCTION: The object of this review is to describe the choroid plexus tumors (CPTs) occurring in the fetus and neonate with regard to clinical presentation, location, pathology, treatment, and outcome. MATERIALS AND METHODS: Case histories and clinical outcomes were reviewed from 93 cases of fetal and neonatal tumors obtained from the literature and our own institutional experience from 1980 to 2016. RESULTS: Choroid plexus papilloma (CPP) is the most common tumor followed by choroid plexus carcinoma (CPC) and atypical choroid plexus papilloma (ACPP). Hydrocephalus and macrocephaly are the presenting features for all three tumors. The lateral ventricles are the main site of tumor origin followed by the third and fourth ventricles, respectively. CPTs of the fetus are detected most often near the end of the third trimester of pregnancy by fetal ultrasound. The extent of surgical resection plays an important role in the treatment and outcome. In spite of excellent survival, which is especially true in the case of CPP, surgical resection may carry significant risks in an immature baby. Given the neonatal low blood volume and increased vascularity of the tumors, there is potential risk for hemorrhage. Although advances in neurosurgical techniques have led to a greater degree of complete surgical resections, survival for the perinatal CPC group remains low even with multimodality therapies. CONCLUSION: Perinatal CPTs have variable overall survivals depending on degree of surgical resection and tumor biology. An increased understanding of the molecular features of these tumors may lead to improved therapies and ultimately survival.

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.

Transventricular Migration of Choroid Plexus Carcinoma Causing an Intraoperative Conundrum: A Case Report with a Review of the Literature.

Migrating intracranial tumors are extremely rare occurrences in the neurosurgery literature. Introduction of any factor causing disequilibrium in cerebrospinal fluid circulation and pressure can potentially precipitate transventricular migration of pedunculated intraventricular lesions. The identification of such factors, prior to excision of intraventricular pedunculated tumors, is imperative to avoid intraoperative mismanagement. We report an extremely rare case of transventricular migration of a choroid plexus carcinoma in an infant, possibly precipitated by a ventriculoperitoneal (VP) shunt on the opposite side. This resulted in intraoperative confusion and a subsequent re-exploration of the opposite side for excision of the tumor. The literature provided only two similar occurrences in the past; however, in both cases, the migration was within the same ventricle and was documented prior to definitive resection. We report the first instance of transventricular migration of a tumor to the opposite ventricle following VP shunt which resulted in a negative intraoperative finding requiring a subsequent re-intervention on the opposite side. We believe that for any pedunculated intraventricular lesion, where an emergency management of hydrocephalus takes priority, a repeat neuroimaging is a must prior to definitive resection.

A new genetically engineered mouse model of choroid plexus carcinoma.

Choroid plexus carcinomas (CPCs) are highly malignant brain tumours predominantly found in children and associated to poor prognosis. Improved therapy for these cancers would benefit from the generation of animal models. Here we have created a novel mouse CPC model by expressing a stabilised form of c-Myc (MycT58A) and inactivating Trp53 in the choroid plexus of newborn mice. This induced aberrant proliferation of choroid plexus epithelial cells, leading to aggressive tumour development and death within 150 days. Choroid plexus tumours occurred with a complete penetrance in all brain ventricles, with prevalence in the lateral and fourth ventricles. Histological and cellular analysis indicated that these tumours were CPCs resembling their human counterparts. Comparison of gene expression profiles of CPCs and non-neoplastic tissues revealed profound alterations in cell cycle regulation and DNA damage responses, suggesting that dysregulation of cell division and DNA checkpoint pathways may represent key vulnerabilities. This novel animal model of CPC provides an invaluable tool to elucidate the mechanism of CPC formation and to develop successful therapies against this devastating paediatric cancer.

Pediatric choroid plexus carcinoma: Biologically and clinically in need of new perspectives.

Choroid plexus (CP) carcinoma is a rare pediatric brain neoplasm. Recent studies have highlighted the potential of genome-wide methylation and gene expression profiling to provide additional layers of information to improve tumor risk-stratification. There is a lack of data regarding the best therapy, and approaches have been heterogeneous. Despite multidisciplinary treatment approaches, the outcome remains guarded and treatments have been based on case series and expert opinions. In this study, we discuss the recent wealth of data regarding CP carcinoma molecular biology and current management. We also briefly highlight the remaining barriers to formulate the best treatment strategies, and future therapeutic potentials.

Roles of the apparent diffusion coefficient and tumor volume in predicting tumor grade in patients with choroid plexus tumors.

PURPOSE: To explore the utility of the apparent diffusion coefficient (ADC) and tumor volume to predict histological grade and prognosis in patients with choroid plexus tumors. METHODS: ADC and tumor volumes were retrospectively evaluated in 25 patients with choroid plexus papilloma (CPP; WHO grade 1 [n = 13]), atypical CPP (aCPP; grade 2 [n = 8]), or choroid plexus carcinoma (grade 3 [n = 4]) The prognostic roles of ADC and tumor volume were assessed. RESULTS: There were significant differences in mean and minimum ADC values, and tumor volume among the WHO grades (p = 0.033, p = 0.044, and p = 0.014, respectively). Receiver-operating characteristic analysis revealed a mean cutoff ADC value ≤ 1.397 × 10-3 mm2/s for aCPP (sensitivity = 0.667, specificity = 0.923). Multiple linear regression analysis demonstrated that both mean ADC (ß = - 0.455, p = 0.005) and tumor volume (ß = 0.513, p = 0.002) were correlated with WHO grade (adjusted R2 = 0.520, p = 0.005). Kaplan-Meier curve analysis identified poorer survival in patients with WHO grade 2 and 3 tumors than in those with WHO grade 1 disease (p = 0.049 and p = 0.012, respectively). A mean ADC ≤ 1.397 × 10-3 mm2/s (p = 0.001) and tumor volume 21.05 ml (p = 0.031) predicted significantly poorer survival. CONCLUSION: Mean ADC and tumor volume were correlated with WHO grade of choroid plexus tumors. A lower ADC value and a larger tumor volume predicted a poorer prognosis.

Glomeruloid Microvascular Proliferation, Desmoplasia, and High Proliferative Index as Potential Indicators of High Grade Canine Choroid Plexus Tumors.

Choroid plexus tumors (CPT) are intraventricular neoplasms accounting for 10% of all primary central nervous system tumors in dogs. They are frequently classified according to the human WHO classification into choroid plexus papilloma (CPP, grade I), atypical CPP (aCPP, grade II), and choroid plexus carcinoma (CPC, grade III). Histological features observed in canine CPT such as increased vascular density (IVD) and glomeruloid microvascular proliferation (GMVP) are not part of the WHO classification. This multi-centric study aimed to investigate tumor-associated vascular hyperplasia in dogs by determining the prevalence of GMVP and IVD in 52 canine CPT and their association with tumor grade. In addition, the expression of angiogenic factors was assessed by immunohistochemistry in 25 tumors to investigate the pathogenesis of tumor-associated vascular hyperplasia. Based on the classical histological hallmarks, this study of 52 CPT identified 22 (42%) CPP (grade I) and 30 of (58%) CPC (grade III). GMVP was more prevalent in CPC (13/30; 43%) than CPP (1/22; 4%), whereas IVD occurred to a similar extent in CPP and CPC. Desmoplasia was more common in CPC (19/30; 63%) than CPP (2/22; 9%), and similarly, the proliferative index (PI) of neoplastic epithelium was significantly higher in CPC (5.14%) than CPP (0.94%). The majority of CPT expressed platelet-derived growth factor (PDGF), PDGFRα, PDGFRß, and vascular endothelial growth factor (VEGF) irrespective of tumor grade or tumor-associated vascular hyperplasia. These results suggest that tumor-associated GMVP, desmoplasia, and PI may serve as histological indicators of malignancy in CPT.

Choroid plexus tumors in adult and pediatric populations: the Cleveland Clinic and University Hospitals experience.

Choroid plexus tumors (CPT) are rare neoplasms accounting for 1-4% of all pediatric brain tumors. They are divided into choroid plexus papilloma (CPP), atypical choroid plexus papilloma (APP) and choroid plexus carcinoma (CPC). CPTs are known to primarily affect children less than 2 years of age. Gross total resection is the most important predictor of survival especially in CPC. Although small case series have been published, limited clinical data are available to describe treatment and outcome of CPTs. More clinical data would be necessary to complete the picture, particularly in populations that are not age limited. Here we share data from the two major hospitals in Cleveland to describe treatment and outcome of adult and pediatric patients. We performed a retrospective analysis of patients with CPT seen in Cleveland Clinic from 1990 to 2015 and at University Hospitals from 1994 to 2015. Results were compared to previously published historical controls. We identified 30 cases with CPT, including 22 pediatric and eight adult cases; 11 females and 19 males. The mean age at presentation was 12.4 years with a median age of 4.5 years (range 2 months-51 years). Gross total surgical resection was achieved in 22, subtotal resection in four, partial resection in two and unknown in two. The histology was CPP in 23 patients, two of whom developed recurrence requiring repeat resection and adjuvant therapy. Median event free survival (EFS) for CPP patients was 7.6 years. The histology was CPC in seven patients. All CPC patients were treated with adjuvant therapy. Median EFS of CPC patients was 4.4 years. Overall survival of all CPT patients was 100% with a median follow up of 7 years. A systematic literature review identified 1012 CPT patients treated from 1989 to 2013. The mean and median age of CPT patients was 13 and 3 years respectively. The median survival of 541 CPP patients was undefined vs. 2.7 years for the 452 CPC patients. The difference between the two populations was highly significant (p < 0.001). Kaplan-Meier survival curves comparing CPTs at Cleveland Clinic and University Hospitals versus a systematic literature review showed a statistically significant advancement in overall survival among the patients treated at Cleveland Clinic and University Hospitals. Our data are consistent with the literature review regarding epidemiology, clinical presentation, and treatment modalities but differed in regards to survival. Differences in survival may be related to different methods of data collection or details in patient care.

A French retrospective study on clinical outcome in 102 choroid plexus tumors in children.

The aim of this study was to review and describe therapeutic approaches in children with choroid plexus tumor (CPT) based on a nationwide series. The World Health Organization classification subdivides these rare tumors into three histological subtypes corresponding to three grades of malignancy: low grade (grade I) choroid plexus papilloma (CPP), intermediate grade (grade II) atypical choroid plexus papilloma (aCPP) and high grade (grade III) choroid plexus carcinoma (CPC). This retrospective study included 102 French children younger than 18 years, treated from 2000 to 2012: 54 CPP, 26 aCPP and 22 CPC. The 5 year overall survival was 100% in CPP, 96.2% in aCPP and 64.7% in CPC. In patients with localized disease, complete surgical resection was achieved in 48/52 CPP, 20/26 aCPP and 7/14 CPC. In this group, patients with complete surgical resection had better event free survival than patients with partial resection (88.9 vs. 41.6%). 28 patients (1 CPP, 6 aCPP and 22 CPC) had adjuvant chemotherapy. 2 aCPP and 9 CPC had radiotherapy. We underlined the need for a central histological review to accurately analyze clinical data; we reported a much higher overall survival for CPC than in most previous CPT series probably including atypical teratoid rhabdoid tumors. In our series, the 5 years overall survival in CPC (64.7%) was higher than event free survival (25.2%) and could be interpreted as a clue for the efficiency of adjuvant/salvage therapy even if the heterogeneity of applied treatments in this retrospective series does not allow for meaningful statistical comparisons.

Preclinical studies of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in pediatric brain tumors.

Chemotherapies active in preclinical studies frequently fail in the clinic due to lack of efficacy, which limits progress for rare cancers since only small numbers of patients are available for clinical trials. Thus, a preclinical drug development pipeline was developed to prioritize potentially active regimens for pediatric brain tumors spanning from in vitro drug screening, through intracranial and intra-tumoral pharmacokinetics to in vivo efficacy studies. Here, as an example of the pipeline, data are presented for the combination of 5-fluoro-2'-deoxycytidine and tetrahydrouridine in three pediatric brain tumor models. The in vitro activity of nine novel therapies was tested against tumor spheres derived from faithful mouse models of Group 3 medulloblastoma, ependymoma, and choroid plexus carcinoma. Agents with the greatest in vitro potency were then subjected to a comprehensive series of in vivo pharmacokinetic (PK) and pharmacodynamic (PD) studies culminating in preclinical efficacy trials in mice harboring brain tumors. The nucleoside analog 5-fluoro-2'-deoxycytidine (FdCyd) markedly reduced the proliferation in vitro of all three brain tumor cell types at nanomolar concentrations. Detailed intracranial PK studies confirmed that systemically administered FdCyd exceeded concentrations in brain tumors necessary to inhibit tumor cell proliferation, but no tumor displayed a significant in vivo therapeutic response. Despite promising in vitro activity and in vivo PK properties, FdCyd is unlikely to be an effective treatment of pediatric brain tumors, and therefore was deprioritized for the clinic. Our comprehensive and integrated preclinical drug development pipeline should reduce the attrition of drugs in clinical trials.