Proteomic identification of biomarkers in the cerebrospinal fluid (CSF) of astrocytoma patients

The monitoring of changes in the protein composition of the cerebrospinal fluid (CSF) can be used as a sensitive indicator of central nervous system (CNS) pathology, yet its systematic application to analysis of CNS neoplasia has been limited. There is a pressing need for both a better understanding of gliomagenesis and the development of reliable biomarkers of the disease. In this report, we used two proteomic techniques, two-dimensional gel electrophoresis (2-DE), and cleavable Isotope-Coded Affinity Tag (cICAT) to compare CSF proteomes to identify tumor- and grade-specific biomarkers in patients bearing brain tumors of differing histologies and grades. Retrospective analyses were performed on 60 samples derived from astrocytomas WHO grade II, III, and IV, schwannomas, metastastic brain tumors, inflammatory samples, and non-neoplastic controls. We identified 103 potential tumor-specific markers of which 20 were high-grade astrocytoma-specific. These investigations allowed us to identify a spectrum of signature proteins that could be used to distinguish CSF derived from control patients versus those with low- (AII) or high-grade (AIV) astrocytoma. These proteins may represent new diagnostic, prognostic, and disease follow-up markers when used alone or in combination. These candidate biomarkers may also have functional properties that play a critical role in the development and malignant progression of human astrocytomas, thus possibly representing novel therapeutic targets for this highly lethal disease.

Durable response of a radiation-induced, high-grade cerebellar glioma to temozolomide

BACKGROUND

Radiation-induced high-grade gliomas are a rare but serious late complication of radiotherapy. We report a patient with radiation-induced cerebellar high-grade glioma who had a durable response to temozolomide.

PATIENTS AND METHODS

Case report of a 77-year-old woman with a radiation-induced, high-grade cerebellar glioma that responded durably to temozolomide.

RESULTS

Our patient developed a cerebellar high-grade glioma 9 years after treatment for a stage IV (T4N0M0) supraglottic laryngeal squamous cell carcinoma with cisplatinum and fluorouracil chemotherapy, and subsequently focal head and neck radiotherapy. Patient was treated with radiation and concurrent temozolomide (only partially due to toxicity) and was stable for 1 year without further adjuvant treatment. Subsequently the tumor recurred and the patient had a dramatic and durable response to standard 5 day dosing of adjuvant temozolomide.

CONCLUSION

High-grade gliomas are a late complication of radiation to the central nervous system and may respond to chemotherapy.

The bad seed: PDGF receptors link adult neural progenitors to glioma stem cells

In this issue of Neuron, Jackson et al. show that adult neural stem cells (B cells) express PDGF receptors. Functional analysis of PDGF signaling in these neural progenitors resonates in provocative ways with an older body of literature on PDGF autocrine loops in malignant glioma and with more recent observations on the bHLH transcription factor Olig2.

Pilot study of the combination of EGFR and mTOR inhibitors in recurrent malignant gliomas

Malignant gliomas are frequently characterized by amplification of the epidermal growth factor receptor (EGFR) and loss of PTEN tumor suppressor gene. Twenty-eight heavily pretreated patients with recurrent malignant gliomas were administered EGFR inhibitors (gefitinib or erlotinib) in combination with the mTOR (mammalian target of rapamycin) inhibitor sirolimus. The regimens were reasonably well tolerated. Nineteen percent of patients experienced a partial response and 50% had stable disease. Six-month progression-free survival for glioblastoma patients was 25%.

Medical management of patients with brain tumors

The most common medical problems in brain tumor patients include the management of seizures, peritumoral edema, medication side effects, venous thromboembolism (VTE), fatigue and cognitive dysfunction. Despite their importance, there are relatively few studies specifically addressing these issues. There is increasing evidence that brain tumor patients who have not had a seizure do not benefit from prophylactic antiepileptic medications. Patients on corticosteroids are at greater risk of Pneumocystis jerovecii pneumonia and may benefit from prophylactic therapy. There is also growing evidence suggesting that anticoagulation may be more effective than inferior vena cava IVC) filtration devices for treating VTE in brain tumor patients and the risk of hemorrhage with anticoagulation is relatively small. Low-molecular weight heparin may be more effective than coumadin. Medications such as modafinil and methylphenidate have assumed an increasing role in the treatment of fatigue, while donepezil and memantine may be helpful with memory loss.

Phase II study of antiangiogenic (metronomic) chemotherapy for recurrent malignant gliomas

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Background: There is preclinical evidence that continuous low-dose chemotherapy may inhibit tumor endothelial proliferation and prevent tumor growth (Browder et al Cancer Res 2000;60:1878). Methods: We conducted a phase II study of continuous low-dose etoposide (VP-16), alternating with cyclophosphamide (CP), in combination with thalidomide (T) and celecoxib (C) in adult patients with recurrent malignant gliomas. There was no limit on the number of prior therapies. Patients received VP-16 [35 mg/m2 (maximum 100 mg) daily for 21 days] alternating with CP [2 mg/kg (maximum 100 mg/day) for 21 days]. Thalidomide was started at 200 mg daily and increased by 100 mg weekly to a maximum of 1200 mg/day, as tolerated. Celecoxib was started at 200 mg twice daily and increased to 400 mg twice daily. MRIs were performed every 6 weeks. Patients were treated until tumor progression or development of unacceptable toxicity. Serum was collected for measurement of angiogenic peptides. Results: 48 patients were enrolled (15 female, 33 male). 28 had glioblastomas (GBM); 20 had anaplastic gliomas (AG). Median age was 53 years (range 33–74); median KPS was 70 (range 60–100). Patients had average of 2.1 prior chemotherapies; 33% had 3 or more prior chemotherapies. Toxicities included neutropenia (8 G3, 8 G4), leukopenia (13 G3, 8 G4), lymphopenia (26 G3), anemia (1 G3), thrombocytopenia (1 G3); nausea (1 G3), vomiting (3 G3), constipation (5 G3; 2 G4), colitis (2 G4), rash (1 G3), dizziness (1 G3); hypoxia (1 G3), and infection (2 G3). 2 patients had DVT and 6 had pulmonary emboli. There were no treatment related deaths. Fatigue was common but usually mild. 12% of patients had PR, 59% had SD, 29% progressed at their first scan. For GBM patients, median progression-free survival (PFS) was 11 weeks, 6 month-PFS was 9% and median survival was 21 weeks. For AG patients, median PFS was 14 weeks; 6 month-PFS was 26% and median survival was 41.5 weeks. Correlation of angiogenic peptide levels and response will be reported. Conclusions: Although there were some responders this regimen did not significantly improve survival in this heavily pretreated group of patients. However, further studies combining metronomic chemotherapy with more potent angiogenesis inhibitors such as lenalidomide or VEGFR inhibitors may be warranted.

[Table: see text]

Development of NG2 neural progenitor cells requires Olig gene function

In the adult central nervous system, two distinct populations of glial cells expressing the chondroitin sulfate proteoglycan NG2 have been described: bipolar progenitor cells and more differentiated "synantocytes." These cells have diverse neurological functions, including critical roles in synaptic transmission, repair, and regeneration. Despite their potential importance, the genetic factors that regulate NG2 cell development are poorly understood, and the relationship of synantocytes to the oligodendroglial lineage, in particular, remains controversial. Here, we show that >90% of embryonic and adult NG2 cells express Olig2, a basic helix-loop-helix transcription factor required for oligodendrocyte lineage specification. Analysis of mice lacking Olig function demonstrates a failure of NG2 cell development at embryonic and perinatal stages that can be rescued by addition of a transgene containing the human OLIG2 locus. These findings show a general requirement for Olig function in NG2 cell development and highlight further roles for Olig transcription factors in neural progenitor cells.

Comparison of linear and volumetric criteria in assessing tumor response in adult high-grade gliomas

The Response Evaluation Criteria in Solid Tumors, or RECIST criteria (one-dimensional [1D] measurement), are widely used to measure response in tumors, but there are few studies evaluating these criteria in brain tumors. We compared linear and volumetric measurements in adult high-grade supratentorial enhancing gliomas to determine the agreement between measurements, in defining responses and in their subsequent relation to survival. We hypothesized that the 1D RECIST criteria maybe suitable for response assessment in adult high-grade gliomas. Tumor size on MRI scans in 104 patients with high-grade enhancing gliomas treated on clinical trial protocols was measured by using 1D (greatest length), 2D (two-dimensional: product of the two longest perpendicular diameters), 3D (three dimensional: product of the longest perpendicular diameters in one plane and the longest orthogonal diameter to that plane), enhancing volume (EV), and total volume (TV). A total of 388 T1 postgadolinium MRI scans (104 baseline and 284 follow-up scans) were evaluated. Volumetric analysis (EV and TV) was performed with commercially available software. Intraobserver and interobserver correlations (rho) were high for all modalities (rho > 0.92 and rho > 0.71, respectively). Correlation was excellent (rho > 0.9) among all modalities except for 3D (rho < 0.6). Patient response rates ranged from 12% to 26%. Median progression-free survival (mPFS) and six-month progression-free survival (6mPFS) were not significantly different among the methods (range, 5.3 months to 5.9 months and 42% to 48%, respectively). Landmark analyses of response at two months using linear methods predicted overall survival with hazard ratios of 0.19 to 0.29 (P < 0.005). These results suggest high concordance among 1D, 2D, TV, and EV, but not 3D, methods in assessing enhancing tumor progression and in estimating mPFS and 6mPFS in adult brain tumor patients. The tumor response at two months assessed by linear methods correlated better with overall survival. Thus, linear methods are comparable to volumetric methods, but simpler to implement for routine clinical use and for designing clinical trials of brain tumors.

Brain metastases

PURPOSE OF REVIEW

Brain metastases occur in 10-30% of cancer patients, and they are associated with a dismal prognosis. Radiation therapy has been the mainstay of treatment for patients without surgically treatable lesions. For patients with good prognostic factors and a single metastasis, surgical resection is recommended. The management of patients with multiple metastases, poor prognostic factors, or unresectable lesions is, however, controversial. Recently published data will be reviewed.

RECENT FINDINGS

Radiation therapy has been shown to substantially reduce the risk of local recurrence after surgical resection of brain metastases, although this does not translate into improved survival. Recently, stereotactic radiosurgery has emerged as an increasingly important alternative to surgery that appears to be associated with less morbidity and similar outcomes. Other potentially promising therapies under investigation include interstitial brachytherapy, new chemotherapeutic agents that cross the blood-brain barrier, and targeted molecular agents.

SUMMARY

Patients with brain metastases are now eligible for a number of treatment options that are increasingly likely to improve outcomes. Randomized, prospective trials are necessary to better define the utility of radiosurgery versus surgery in the management of patients with brain metastases. Future investigations should address quality of life and neurocognitive outcomes, in addition to traditional outcome measures such as recurrence and survival rates. The potentially substantial role for chemotherapeutics that cross the blood-brain barrier and for novel targeted molecular agents is now being elucidated.

Vector control in leishmaniasis

Indoor residual spraying is a simple and cost effective method of controlling endophilic vectors and DDT remains the insecticide of choice for the control of leishmaniasis. However resistance to insecticide is likely to become more widespread in the population especially in those areas in which insecticide has been used for years. In this context use of slow release emulsified suspension (SRES) may be the best substitute. In this review spraying frequencies of DDT and new schedule of spray have been discussed. Role of biological control and environment management in the control of leishmaniasis has been emphasized. Allethrin (coil) 0.1 and 1.6 per cent prallethrin (liquid) have been found to be effective repellents against Phlebotomus argentipes, the vector of Indian kalaazar. Insecticide impregnated bednets is another area which requires further research on priority basis for the control of leishmaniasis. Role of satellite remote sensing for early prediction of disease by identifying the sandflygenic conditions cannot be undermined. In future synthetic pheromons can be exploited in the control of leishmaniasis.

Therapy for recurrent malignant glioma in adults

Malignant gliomas are the most common form of primary brain tumors in adults. Although the prognosis remains poor, there has been recent progress in the treatment of these tumors. Standard therapy for patients with this disease will be reviewed, together with more novel approaches such as targeted molecular therapies, angiogenesis inhibitors, immunotherapies, gene therapies and intratumoral therapies.

Characterization of lymphocytic infiltrates in progressive multifocal leukoencephalopathy: Co-localization of CD8+T cells with JCV-infected glial cells

We characterized inflammatory infiltrates in archival brain biopsy and autopsy samples from 26 HIV(+) and 20 HIV(-) patients with progressive multifocal leukoencephalopathy (PML). The predominant inflammatory cells were CD8(+) T lymphocytes. We defined CD8(+) T cell distribution with regard to JCV-infected glial cells, PML lesions and the extent of demyelination. In most samples from either HIV(+) and HIV(-) patients, we found positive correlations between the parenchymal CD8(+) T cells and JCV-infected glial cells and conversely, negative correlations between the perivascular CD8(+) T cells and JCV-infected glial cells in the surrounding brain. Most of these correlations remained significant after accounting for the degree of demyelination and location of the cells relative to lesions. Moreover, high numbers of CD8(+) T cells were found within and at the border of active PML lesions. These results suggest that CD8(+) T cells are primarily associated with JCV-infected glial cells in most PML cases and that an active ongoing recruitment of CD8(+) T cells and possibly viral antigen-specific retention could occur. These observations are discussed in the context of the recent evidence of PML in multiple sclerosis and Crohn's patients treated with natalizumab, underscoring the role of CD8(+) T lymphocytes in continued immunosurveillance of the CNS.

Targeted molecular therapy of malignant gliomas

Malignant gliomas are the most common form of primary brain tumors in adults. Despite advances in diagnosis and standard therapies such as surgery, radiation, and chemotherapy, the prognosis remains poor. Recent scientific advances have enhanced our understanding of the biology of gliomas and the role of tyrosine kinase receptors and signal transduction pathways in tumor initiation and maintenance, such as the epidermal growth factor receptors, platelet-derived growth factor receptors, vascular endothelial growth factor receptors, and the Ras/Raf/mitogen-activated protein (MAP)-kinase and phosphatidylinositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathways. Novel targeted drugs such as small molecular inhibitors of these receptors and signaling pathways are showing some activity in initial studies. As we learn more about these drugs and how to optimize their use as single agents and in combination with radiation, chemotherapy, and other targeted molecular agents, they will likely play an increasing role in the management of this devastating disease. This review summarizes the current results with targeted molecular agents in malignant gliomas and strategies under evaluation to increase their effectiveness.

Evaluation of a dot-immunoblot assay for detecting leishmanial antigen in naturally infected Phlebotomus argentipes (Diptera: Psychodidae)

A simple and highly reproducible dot-immunoblot assay was developed to detect leishmanial antigen in Phlebotomus argentipes that were naturally infected with Leishmania donovani. The test was sensitive to as little as 10 ng of antigenic protein (equivalent to the gut content of one laboratory-infected sandfly) and also appeared to be specific, in that it gave a positive result with some P. argentipes (the primary vector of L. donovani in India) and L. donovani but not with P. papatasi or other pathogens. When used to investigate a large number of sandflies collected from two areas of the Indian state of Bihar where visceral leishmaniasis is endemic, the assay appeared sufficiently sensitive and specific to detect the naturally infected insects. The simplicity, reproducibility, high sensitivity and high specificity of the assay should make it useful for field studies, particularly in determining the prevalence of sandfly infection, the local level of transmission, and the impact of vector-control programmes.

Targeted molecular therapy of malignant gliomas

Malignant gliomas are the most common form of primary brain tumors in adults. Despite advances in diagnosis and standard therapies such as surgery, radiation, and chemotherapy, the prognosis remains poor. Recent scientific advances have enhanced our understanding of the biology of gliomas and the role of tyrosine kinase receptors and signal transduction pathways in tumor initiation and maintenance, such as the epidermal growth factor receptors, platelet-derived growth factor receptors, vascular endothelial growth factor receptors, and the Ras/Raf/mitogen-activated protein (MAP)-kinase and phosphatidylinositol-3 kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathways. Novel targeted drugs such as small molecular inhibitors of these receptors and signaling pathways are showing some activity in initial studies. As we learn more about these drugs and how to optimize their use as single agents and in combination with radiation, chemotherapy, and other targeted molecular agents, they will likely play an increasing role in the management of this devastating disease. This review summarizes the current results with targeted molecular agents in malignant gliomas and strategies under evaluation to increase their effectiveness.

Malignant gliomas

Malignant gliomas are the most common type of primary brain tumor. Although therapy for patients with these tumors remains limited, there has been important progress recently. In this review, some of these advances are discussed, with an emphasis on targeted molecular therapies.

Susceptibility of Phlebotomus argentipes against DDT in endemic Districts of North Bihar, India

Susceptibility status of Indian kala-azar vector Phlebotomus argentipes after DDT spray from endemic areas of Muzaffarpur and Vaishali district and unsprayed non-endemic area of Patna district, Bihar, India were compared. Higher Lc50 viz. 2.6% and 3.2% and LT50, values 51.0 and 69.0 minutes to 4% DDT were observed for P. argentipes of Muzaffarpur and Vaishali district, whereas P. argentipes of Patna district was 100% susceptible to same concentration, indicating increased tolerance in P. argentipes. It is concluded DDT resistant P. argentipes, particularly in endemic zone growing. The possible explanation could be long-term insecticidal pressure.