Intraoperative consultation on pediatric central nervous system tumors by squash cytology

Squash cytology (SC) is a very useful procedure during neurosurgical intraoperative consultation (IOC), and it is especially recommended for the evaluation of soft tumors or tumors that are highly cellular (just the characteristics of pediatric central nervous system [CNS] tumors). The aim of this review is to familiarize pathologists with the range of cytomorphologic appearances that can occur during IOC for pediatric CNS tumors and with the diagnostic dilemmas and pitfalls encountered in this setting. This article is based on the medical literature and the authors' experience with a large series of cases accrued over a 12‐year period at 3 institutions. SC is a specially recommended procedure in IOC for pediatric CNS tumors; it reveals the fine cellular details and background features in a manner not seen in corresponding frozen sections. Indeed, a differential diagnosis between histologically look‐alike processes can be achieved with more confidence if SC is employed. Cancer (Cancer Cytopathol) 2015;123:331–46. © 2015 American Cancer Society.     

Pediatric brain tumors: mutations of two dioxygenases (hABH2 and hABH3) that directly repair alkylation damage

Alkylating agents, commonly used for brain tumor therapy, induce DNA and RNA lesions that, if not repaired, drive cells to apoptosis. Thus, cellular mechanisms that are responsible for nucleic acid repair are possibly involved in drug resistance. This work analyzes hABH2 and hABH3, two human Fe(II)-dependent dioxygenases in pediatric brain tumors that are treated with alkylating agents. We analyzed 25 brain tumor samples for hABH2 and hABH3 mutations; a subset of samples was tested for quantitative expression with Real-Time PCR. Sequencing analysis showed two new mutations in two glioma patients, one of hABH2 coding sequence (I141 V) and the other of hABH3 (D189 N). The mutation at codon 189 falls in a crucial region of the protein. All subjects analyzed by Real-Time PCR showed an enhanced expression of the two genes, particularly of hABH2. This is the first study of hABH2 and hABH3 in pediatric brain tumors; further molecular investigations of their mutations and expression may help determine their role in response to chemotherapy.     

New agents in the treatment of primary brain tumors

Summary A review of single agent trials of cytotoxic agents in adults with high grade gliomas is presented. The rationale for testing these agents in patients with brain tumors was variable and is discussed. The criteria to evaluate responses were also variable ranging from subjective evaluation of clinical improvement with a stable radiographic assessment to the same objective response criteria utilized for solid tumors. Trials of agents specifically designed for brain tumors such as AZQ and spiromustine have been disappointing. There are encouraging results being seen in early trials of newer agents which await confirmation in larger trials but which hold promise for improving the disappointing results seen so far with chemotherapy in primary brain tumors.     

Establishment and characterization of MRT cell lines from genetically engineered mouse models and the influence of genetic background on their development

Malignant rhabdoid tumors (MRTs) are rare, aggressive cancers occuring in young children primarily through inactivation of the SNF5(INI1, SMARCB1) tumor suppressor gene. We and others have demonstrated that mice heterozygous for a Snf5 null allele develop MRTs with partial penetrance. We have also shown that Snf5^+/? mice that lack expression of the pRb family, due to TgT₁₂₁ transgene expression, develop MRTs with increased penetrance and decreased latency. Here, we report that altering the genetic background has substantial effects upon MRT development in Snf5^+/?‐ and TgT₁₂₁;Snf5^+/? mice, with a mixed F1 background resulting in increased latency and the appearance of brain tumors. We also report the establishment of the first mouse MRT cell lines that recapitulate many features of their human counterparts. Our studies provide further insight into the genetic influences on MRT development as well as provide valuable new cell culture and genetically engineered mouse models for the study of CNS‐MRT etiology.     

In vivo models of primary brain tumors: pitfalls and perspectives

Animal modeling for primary brain tumors has undergone constant development over the last 60 years, and significant improvements have been made recently with the establishment of highly invasive glioblastoma models. In this review we discuss the advantages and pitfalls of model development, focusing on chemically induced models, various xenogeneic grafts of human cell lines, including stem cell-like cell lines and biopsy spheroids. We then discuss the development of numerous genetically engineered models available to study mechanisms of tumor initiation and progression. At present it is clear that none of the current animal models fully reflects human gliomas. Yet, the various model systems have provided important insight into specific mechanisms of tumor development. In particular, it is anticipated that a combined comprehensive knowledge of the various models currently available will provide important new knowledge on target identification and the validation and development of new therapeutic strategies.     

Gender differences in facial expression recognition in survivors of pediatric brain tumors

Objective: To examine the relation between gender, history of cranial radiation therapy (CRT) and facial expression recognition (FER) skill in survivors of pediatric brain tumors. Methods: Fifty‐three survivors (27 females) completed a measure of FER and an intelligence test. Results: There was a significant interaction between gender and CRT on ability to interpret low‐intensity facial expressions, such that females who had not had CRT made fewer errors than either females who had CRT or males. Conclusion: A history of CRT has a notable effect on FER skill in females: girls who received CRT performed significantly more poorly than girls who did not. Copyright © 2008 John Wiley & Sons, Ltd.     

Proton radiotherapy for pediatric central nervous system ependymoma: clinical outcomes for 70 patients

Background

Ependymoma is treated with maximal surgical resection and localized radiotherapy. Minimizing unnecessary exposure to radiation is of paramount importance for young children. Proton radiotherapy (PRT) spares healthy tissues outside the target region, but reports of clinical outcomes are scarce. We report outcomes for 70 patients treated with PRT for intracranial ependymoma.

Methods

Seventy patients with localized ependymoma treated with involved-field PRT at the Massachusetts General Hospital between October 2000 and February 2011 were included.

Results

Median age at diagnosis was 38 months (range, 3 mo–20 y). Nineteen (27%) patients had supratentorial ependymoma and 51(73%) had infratentorial ependymoma. Forty-six (66%) had gross total resection (GTR), and 24 (34%) had subtotal resection (STR). At a median follow-up of 46 months, 3-year local control, progression-free survival, and overall survival were 83%, 76%, and 95%, respectively. STR was significantly associated with worse progression-free survival (54% vs 88%, P = .001) and overall survival (90% vs 97% for GTR, P = .001). In a subset of patients (n = 14), mean intelligence was 108.5 at baseline and 111.3 after mean 2.05 years of follow-up. In a larger group of patients (n = 28), overall adaptive skills were 100.1 at baseline and 100.8 after 2.21 years of follow-up. Few patients developed evidence of growth hormone deficiency, hypothyroidism, or hearing loss.

Conclusion

Outcomes for children treated with PRT compare favorably with the literature. STR correlated with inferior outcome. The young age at diagnosis and the proximity of critical structures in patients with ependymoma make PRT an ideal radiation modality.     

Primary brain lymphomas in patients with a prior or concomitant malignancy

The increased incidence of second malignancies among cancer survivors is well documented. Thus, differential diagnosis between metastatic spread from a prior malignancy and the occurrence of a new neoplasm should be considered. This isparticularly difficult for brain lesions due to their poor prognosis that often discourages diagnostic work-up. In some cases diagnosisof a second primary neoplasm, such as primary central nervoussystem lymphomas (PCNSL), could change the therapeutic managementand the prognosis. About 8% of PCNSL occurs as a second malignancy.Homogeneous and intense tomographic enhancement, deep location of lesions and dramatic response to corticosteroids are suggestive for PCNSL and should be carefully considered before the startof treatment for cerebral lesions. Prognosis and standard management of brain metastases and PCNSL are almost completely different. In addition, while treatment of brain metastases oftenhas a palliative purpose the goal in PCNSL treatment is the cure.Four patients with PCNSL as a second malignancy are reported and literature is reviewed. Diagnosis of PCNSL changes the strategyof treatment which could have a critical therapeutic and prognosticimpact.     

Physical functioning in pediatric survivors of childhood posterior fossa brain tumors

Background

Survival rates for children diagnosed with posterior fossa brain tumors (PFBTs) have improved significantly over the past several decades, and long-term functioning assessments have become priorities. These evaluations have occurred frequently in adults but only rarely in children. This study describes a cross-sectional assessment of physical functioning in pediatric survivors of PFBTs using the Bruininks-Osteretsky Test of Motor Performance, Second Edition (BOT-2).

Methods

Primary analyses compared BOT-2 scores to normative data using 1-sample t tests for each gross motor subscale (Bilateral Coordination, Balance, Running Speed/Agility, Strength) and motor-area composite (Body Coordination and Strength and Agility). Second, the cohort was stratified by diagnostic or treatment variables. Group differences and groups vs norms were evaluated using independent 2-sample and 1-sample t tests, respectively. Primary analyses compared BOT-2 scores with normative data using 1-sample t tests for each gross motor subscale (Bilateral Coordinationcoordination, Balance, Running Speed/Agility, Strength) and motor-area composite (Body Coordination and Strength and Agility). Second, the cohort was stratified by diagnostic or treatment variables. Group differences and groups vs norms were evaluated using independent 2-sample and 1-sample t tests, respectively.

Results

Mean age of 30 participants was 11.4 years (range, 4.9y–18.2y), and mean time from diagnosis was 6.1 years (range, 1.1y–16.7y). Cerebellar astrocytoma (43.3%) and medulloblastoma (40%) were the most common diagnoses. As a group, significantly decreased functioning, compared with norms, was observed in Balance (P < .001) and Running Speed/Agility (P = .005). Specifically in Balance, 21 (70%) participants performed below or well-below average. Participants with a non-astrocytoma performed significantly lower than norms in all areas, independent of age at diagnosis. Survivors with tumors infiltrating the vermis demonstrated significantly lower Body Coordination than norms (P < .001).

Conclusions

Pediatric survivors of PFBTs demonstrated decreased physical functioning, most notably in Balance. These data underscore the need for further research and implementation of physical activity programs aimed specifically at approaches to minimize physical limitations.     

Parental smoking and risk of childhood brain tumors

Childhood brain tumors (CBT) are the leading cause of cancer death in children, yet their etiology remains largely unknown. Tobacco smoke contains 61 known carcinogens and increases the risk of several adult cancers. This study investigated associations between parental smoking and risk of CBT in a population‐based case–control study conducted between 2005 and 2010. Cases were identified through all ten Australian pediatric oncology centers, controls via nationwide random‐digit dialing, frequency matched to cases on age, sex and state of residence. Parental smoking information was obtained for 302 cases and 941 controls through mailed questionnaires that requested average daily cigarette use in each calendar year from age 15 to the child's birth, linked to residential and occupational histories. Data were analyzed using unconditional logistic regression, adjusting for frequency matching variables and potential confounders. Overall, parental smoking before or during pregnancy showed no association with CBT risk. The odds ratios for maternal smoking before and during pregnancy were 0.99 (95% CI: 0.70, 1.40) and 0.89 (95% CI: 0.61, 1.21), respectively, and those for paternal smoking before and during pregnancy were 0.99 (95% CI: 0.71, 1.38) and 1.04 (95% CI: 0.74, 1.46), respectively. In children under 24 months of age, the odds ratios for maternal smoking preconception and during pregnancy were 5.06 (95% CI 1.35–19.00) and 4.61 (95% CI: 1.08, 19.63), although these results were based on modest numbers. Future studies should investigate the associations between maternal smoking and risk of CBT by the child's age of diagnosis.     

A phase 1 and pharmacokinetic study of enzastaurin in pediatric patients with refractory primary central nervous system tumors: a pediatric brain tumor consortium study

BackgroundWe sought to estimate the maximum tolerated or recommended phase 2 dose and describe the pharmacokinetics and toxicities of enzastaurin, an oral inhibitor of protein kinase Cβ, in children with recurrent central nervous system malignancies.MethodsEnzastaurin was administered continuously once daily at 3 dose levels (260, 340, and 440 mg/m²) and twice daily at 440 mg/m²/day. Plasma pharmacokinetics were evaluated following a single dose and at steady state. Inhibition of protein kinase C and Akt cell signaling in peripheral blood mononuclear cells was evaluated. Akt pathway activity was measured in pretreatment tumor samples.ResultsThirty-three patients enrolled; 1 was ineligible, and 3 were nonevaluable secondary to early progressive disease. There were no dose-limiting toxicities during the dose-finding phase. Two participants receiving 440 mg/m² given twice daily experienced dose-limiting toxicities of grade 3 thrombocytopenia resulting in delayed start of course 2 and grade 3 alanine transaminase elevation that did not recover within 5 days. There were no grade 4 toxicities during treatment. The concentration of enzastaurin increased with increasing dose and with continuous dosing; however, there was not a significant difference at the 440 mg/m² dosing level when enzastaurin was administered once daily versus twice daily. There were no objective responses; however, 11 participants had stable disease >3 cycles, 7 with glioma, 2 with ependymoma, and 2 with brainstem glioma.ConclusionEnzastaurin was well tolerated in children with recurrent CNS malignancies, with chromaturia, fatigue, anemia, thrombocytopenia, and nausea being the most common toxicities. The recommended phase 2 dose is 440 mg/m²/day administered once daily.     

Calmodulin content in human central nervous system tumors

Summary Benign and malignant brain tumors and normal cerebral cortex were assayed for calmodulin content by enzymatic and radioimmunoassay techniques. Normal cerebral cortex contained more (8.31 ± 1.27 vs 3.30 ± 0.42 µg/mg protein) calmodulin than the brain tumors. The contents of calmodulin in the malignant glioblastomas were significantly higher than the meningiomas (5.41 ± 0.31 vs 2.97 ± 0.16 µg/mg protein). These differences were independent of tumor location and persisted when calmodulin content was normalized for DNA rather than protein content. This data supports differences in the tissue calmodulin contents with normal cortex> primary malignant tumors> benign tumors> metastatic tumor tissue.     

Dose distribution effects of spot-scanning proton beam therapy equipped with a multi-leaf collimator for pediatric brain tumors

The present study simulated the effect of spot-scanning proton beam therapy (PBT) performed using a device equipped with a multi-leaf collimator (MLC) to calculate the dose distribution. Simulation studies using 18 pediatric patients with brain tumors in the posterior fossa were performed. Treatment plans were created for the MLC at different stages: Fully open (initial plan), fully closed to allow an irradiated area extending to 15 mm from the clinical target volume (CTV) (15-mm plan), or closing only the leaves where an organ at risk (OAR) overlapped with a border at 10 or 5 mm from the CTV (10- and 5-mm plans, respectively). The mean dose values for the brainstem, cervical cord, brain and cochlea in all MLC closure plans decreased as the MLC was closed (P=9.9×10⁻¹⁰, P=1.3×10⁻¹⁷, P=2.1×10⁻¹⁶ and P=2.0×10⁻⁵, respectively). The maximum dose (D_max) values of the cervical cord and cochlea in all MLC closure plans were also decreased as the MLC was closed (P=3.0×10⁻⁴ and P=1.1×10⁻⁵, respectively). The dose to the CTV was almost unchanged. In 10 patients, the D_max of the brain in all MLC-closure plans was higher than that of the initial plan, but the maximum increase was only 0.8 gray relative biological effectiveness [Gy(RBE)]. In conclusion, the existing MLC installed in the treatment device can be used to decrease the OAR dose significantly using spot-scanning PBT without a large capital investment. The dose from the scattered particles was small.     

Pneumocystis carinii pneumonia in HIV negative patients with primary brain tumors

Background: Pneumocystis carinii pneumonia (PCP) is an opportunistic infection with rather adverse outcomes. An unexpected increase in cases of PCP was noted in the brain tumor population at the Johns Hopkins Hospital (JHH) in 2000. This prompted the present review of the clinical features and risk factors for PCP in the human immunodeficiency virus (HIV) negative brain tumor population. Methods: The study was located at the JHH. A retrospective review of medical records was done to identify patients with discharge diagnosis of PCP from 1980 to 2001. Patients who were HIV positive were excluded. A detailed analysis was done of patients with brain tumors. Results: From 1980 to 2001, 468 cases of PCP were identified, diagnosed histologically or clinically, of which 110 were patients with an underlying malignancy. Of the 110 cases 15 were seen in the brain tumor population. Of these, 6 patients were seen in 2000 and one in early 2001. Three of these had primary central nervous system (CNS) lymphoma (PCNSL) on high dose methotrexate. Eight of the fifteen episodes (53.3%) were fatal despite institution of antibiotics and supportive therapy. Conclusion: The incidence and mortality due to Pneumocystis carinii among the brain tumor population is increasing. While corticosteroids are known immunosupressants, prescribing patterns for these medications has not changed lately. However, high dose methotrexate is now being used in PCNSL and could be a complicating factor. Since effective prophylaxis exists, it should be considered in patients with brain tumors receiving high dose steroids, high dose methotrexate or with lymphopenia.     

Invasiveness of primary brain tumors

Summary Primary malignant neoplasms of the nervous system differ from other types of malignancy in several ways. Clinical progression is due to local invasive growth, while metastases outside the skull are rare. The tumors show no sharp delimitation from the surrounding normal tissue. At the edge, an ill-defined area of invasive tumor cells, reacting glial cells and inflammatory cells is present. At the same time the primary brain tumors are biologically heterogeneous.In this review, a short survey of markers for malignancy in primary brain tumors is given, and some properties of importance for invasive behavior, are listed. These include different cellular enzymes, phagocytotic property, locomotive and proliferative characteristics.Studies of primary brain tumors in situ show invasive growth into the surrounding brain tissue, often tollowed by hemorrhage and necrosis. In addition spread of tumor cells takes place along preexisting intracranial structures. Recently, several systems for the study of brain tumor invasiveness in culture have been elaborated. Both experimental and human gliomas have been tested. The target tissues include organ culture of embryonic chick heart muscle, chorioallantoic membrane, fetal rat brain tissue and reconstructed vessel walls. It has been shown that glioma cells are able to split junctions between normal cells. They destroy and phagocytose the normal cells and penetrate the normal tissue. The use of brain tissue and reaggregated brain cell cultures as target for glioma cells in culture opens the possibility for an elucidation of invasiveness as one of the most important properties of malignancy in the nervous system.     

Cell-surface antigen profiling of pediatric brain tumors: B7-H3 is consistently expressed and can be targeted via local or systemic CAR T-cell delivery

BackgroundImmunotherapy with chimeric antigen receptor (CAR) T cells is actively being explored for pediatric brain tumors in preclinical models and early phase clinical studies. At present, it is unclear which CAR target antigens are consistently expressed across different pediatric brain tumor types. In addition, the extent of HLA class I expression is unknown, which is critical for tumor recognition by conventional αβTCR T cells.MethodsWe profiled 49 low- and high-grade pediatric brain tumor patient-derived orthotopic xenografts (PDOX) by flow analysis for the expression of 5 CAR targets (B7-H3, GD2, IL-13Rα2, EphA2, and HER2), and HLA class I. In addition, we generated B7-H3-CAR T cells and evaluated their antitumor activity in vitro and in vivo.ResultsWe established an expression hierarchy for the analyzed antigens (B7-H3 = GD2 >> IL-13Rα2 > HER2 = EphA2) and demonstrated that antigen expression is heterogenous. All high-grade gliomas expressed HLA class I, but only 57.1% of other tumor subtypes had detectable expression. We then selected B7-H3 as a target for CAR T-cell therapy. B7-H3-CAR T cells recognized tumor cells in an antigen-dependent fashion. Local or systemic administration of B7-H3-CAR T cells induced tumor regression in PDOX and immunocompetent murine glioma models resulting in a significant survival advantage.ConclusionsOur study highlights the importance of studying target antigen and HLA class I expression in PDOX samples for the future design of immunotherapies. In addition, our results support active preclinical and clinical exploration of B7-H3-targeted CAR T-cell therapies for a broad spectrum of pediatric brain tumors.     

Phase II study of homoharringtonine in patients with recurrent primary malignant central nervous system tumors

A phase 11 trial of Homoharringtonine (HHT) was performed in 15 patients with recurrent or progressive malignant glioma. The drug was administered at a initial dose of 4 mg/m²/day by continuous 5 day intravenous infusion (3 mg/m²/day x 5 days for heavily pretreated patients). Courses were repeated every 3–4 weeks upon recovery from toxicity. No objective antitumor regressions occurred. Two patients had no change in their CT brain scans for 2–3 months and one patient had stable disease for 6 months. Toxicity was tolerable and included myelosuppression and occasionally mild hypotension. Chemosensitivity testing with HHT and several other chemotherapy drugs was performed in glioma cell lines, including cell lines derived from these patients. The results suggest that HHT is an inactive drug in malignant glioma using this dose schedule.     

Absence of human cytomegalovirus infection in childhood brain tumors

Human cytomegalovirus (HCMV) is a common human pathogen which induces different clinical manifestations related to the age and the immune conditions of the host. HCMV infection seems to be involved in the pathogenesis of adult glioblastomas. The aim of our study was to detect the presence of HCMV in high grade gliomas and other pediatric brain tumors. This hypothesis might have important therapeutic implications, offering a new target for adjuvant therapies. Among 106 pediatric patients affected by CNS tumors we selected 27 patients with a positive HCMV serology. The serological analysis revealed 7 patients with positive HCMV IGG (≥14 U/mL), whom had also a high HCMV IgG avidity, suggesting a more than 6 months-dated infection. Furthermore, HCMV IGM were positive (≥22 U/mL) in 20 patients. Molecular and immunohistochemical analyses were performed in all the 27 samples. Despite a positive HCMV serology, confirmed by ELISA, no viral DNA was shown at the PCR analysis in the patients’ neoplastic cells. At immunohistochemistry, no expression of HCMV antigens was observed in tumoral cells. Our results are in agreement with recent results in adults which did not evidence the presence of HCMV genome in glioblastoma lesions. We did not find any correlation between HCMV infection and pediatric CNS tumors.