Incomplete tumour control following DNA vaccination against rat gliomas expressing a model antigen.

BACKGROUND: Vaccination against tumour-associated antigens is one approach to elicit anti-tumour responses. We investigated the effect of polynucleotide (DNA) vaccination using a model antigen (E. coli lacZ) in a syngeneic gliosarcoma model (9L). METHODS: Fisher 344 rats were vaccinated thrice by intramuscular injection of a lacZ-encoding or a control plasmid in weekly intervals. One week after the last vaccination, lacZ-expressing 9L cells were implanted into the striatum. RESULTS: After 3 weeks, in lacZ-vaccinated animals the tumours were significantly smaller than in control-vaccinated animals. In cytotoxic T cell assays lysis rates of >50 % could only be observed in a few of the lacZ-vaccinated animals. This response was directed against lacZ-expressing and parental 9L cells but not against syngeneic MADB 106 adenocarcinoma cells. In Elispot assays interferon-γ production was observed upon stimulation with 9LlacZ and 9L wild-type but not MADB 106 cells. This response was higher for lacZ-immunized animals. All animals revealed dense infiltrates with CD8+ lymphocytes and, to a lesser extent, with NK cells. CD25-staining indicated cells possibly associated with the maintenance of peripheral tolerance to self-antigens. All tumours were densely infiltrated by microglia consisting mostly of ramified cells. Only focal accumulation of macrophage-like cells expressing ED1, a marker for phagocytic activity, was observed. CONCLUSION: Prophylactic DNA vaccination resulted in effective but incomplete suppression of brain tumour formation. Mechanisms other than cytotoxic T cell responses as measured in the generally used in vitro assays appear to play a role in tumour suppression.

A rare case of extradural lumbar nerve root cavernoma.

We present a very rare case of an extradural nerve root cavernoma of the lumbar spine. The patient had signs of radiculopathy for the last 3 years. Conservative treatment was unsuccessful. The MRI-image revealed a lesion mimicking neurinoma of the left L3 nerve root. Surgical removal of the lesion was performed by an extreme lateral transmuscular approach. Intraoperatively, the lesion showed signs of intratumoural bleeding. In the histological analysis, a cavernoma of the nerve root was established. Despite the benign nature of these very rare lesions, complete surgical removal should be performed since a spontaneous regression is not to be expected and surgery relieves the patients from their symptoms.

Gliosarcoma: clinical experiences and additional information with MR spectroscopy.

Gliosarcomas represent about 2% of glioblastoma multiforme (WHO grade IV). They have mixed features of glial and sarcomatous components. The clinical presentation and prognosis are similar to glioblastoma. Between 1997 and 2006, 16 patients with intracranial gliosarcoma were treated in the Department of Neurosurgery in Kiel, Germany. Median age was 63 years (52-79 years). Eleven patients were men and five were women. Six tumors were in the frontal lobe, four in the temporal lobe, three parietal, two in the thalamic area and one in the occipital lobe. Pre-operatively, in two patients, we could perform magnetic resonance (MR) spectroscopy. There was lactate peak, which is a sign of local necrosis and hypoxia. Median survival time in our patient group was 7 months (2-11 months). On histological examination, we found glial fibrillary acid protein positive cells surrounded by sarcomatous tissue and reticular fibers. The proliferation index MIB-1 was between 20 and 70%. The prognosis in this patient group is still poor. MR spectroscopy and location of the tumor adjacent to the dura with inhomogeneous contrast enhancement might give hints pre-operatively for the differential diagnosis of gliosarcoma. Further works with adjuvant chemotherapy are necessary.

Outcome of cerebral amyloid angiopathic brain haemorrhage.

BACKGROUND: Abnormal amyloid protein can be deposited in the wall of cerebral arteries leading to fragility and intracerebral haematoma in patients with cerebral amyloid angiopathy. Diagnosis can be done only histologically. The indication of surgically treating intracerebral haemorrhage caused by amyloid angiopathy is controversial. There are studies showing a high mortality and a high rate of recurrent bleeding. Others show almost no recurrent bleeding and a very low mortality and a third party states that even when recurrent intracerebral haemorrhage occurs, re-evacuation should be performed. In the present retrospective study a population of 99 patients suffering from cerebral amyloid angiopathy-related cerebral haemorrhage has been studied, to investigate the surgical outcome. METHOD: Ninety-nine patients were histologically diagnosed with cerebral amyloid angiopathy in our department from 1991-2004. The outcome has been established by the Glascow Outcome Score. FINDINGS: It could be shown that intraventricular bleeding and age >75 years increased the mortality after operative evacuation. Recurrent bleeding occurred in 22% of patients. After re-evacuation at least half of the patients survived leading to the suggestion to re-operate a recurrent bleeding since patients have a chance to survive even when the Glascow Outcome Score is 3. The overall mortality in the observed population was 16% and 11% had a very good neurological recovery based on a Glascow Outcome Score of 4-5. The operative outcome in amyloid angiopathy related intracerebral haemorrhage is similar to this of intracerebral haemorrhage induced by other causes like hypertensive bleeding. CONCLUSIONS: Possible cerebral amyloid angiopathy is no contraindication for evacuation of brain-haematoma, and especially not in patients younger than 75 years old without an intraventricular haemorrhage.

Clinical and histological features of multiple meningiomas compared with solitary meningiomas.

Between 1991 and 2002, 456 patients with an intracranial meningioma were treated. Thirty-nine of these had more than one meningioma (8.6%). The mean age was 58 years (27-85 years). Sex distribution was 8.8:1 (35 female, four male). There was no associated spinal meningioma. No patient had neurofibromatosis. In 19 patients all meningiomas were removed. Twelve showed the same histology, seven had different histological features. In the remaining 20 patients only the symptomatic meningioma was removed. Recurrences occurred in 11 patients (28.2%). Six patients died during follow-up. Multiple meningiomas have their own clinical features. Besides a high female preponderance, PR expression was stronger in multiple meningiomas than in solitary meningiomas while p53 status and MIB-1 LI were similar between the two groups. Progesterone receptor, p53 status and MIB-1 LI were valuable markers for predicting a patient's outcome in multiple meningiomas. The number of meningiomas is growing in patients with recurrent meningiomas.

Molecular profiling of chordoma.

The molecular basis of chordoma is still poorly understood, particularly with respect to differentially expressed genes involved in the primary origin of chordoma. In this study, therefore, we compared the transcriptional expression profile of one sacral chordoma recurrence, two chordoma cell lines (U-CH1 and U-CH2) and one chondrosarcoma cell line (U-CS2) with vertebral disc using a high-density oligonucleotide array. The expression of 65 genes whose mRNA levels differed significantly (p<0.001; ≥6-fold change) between chordoma and control (vertebral disc) was identified. Genes with increased expression in chordoma compared to control and chondrosarcoma were most frequently located on chromosomes 2 (11%), 5 (8%), 1 and 7 (each 6%), whereas interphase cytogenetics of 33 chordomas demonstrated gains of chromosomal material most prevalent on 7q (42%), 12q (21%), 17q (21%), 20q (27%) and 22q (21%). The microarray data were confirmed for selected genes by quantitative polymerase chain reaction analysis. As in other studies, we showed the expression of brachyury. We demonstrate the expression of new potential candidates for chordoma tumorigenesis, such as CD24, ECRG4, RARRES2, IGFBP2, RAP1, HAI2, RAB38, osteopontin, GalNAc-T3, VAMP8 and others. Thus, we identified and validated a set of interesting candidate genes whose differential expression likely plays a role in chordoma.

Expression of the chemokines CXCL12 and CX3CL1 and their receptors in human nerve sheath tumors.

Peripheral nerve sheath tumors are in most cases slowly growing neoplasms that can be adequately cured by surgical resection. However, facing the risk of a neurosurgical intervention and the trend of multiple relapses of nerve sheath tumors the development of additional therapy strategies seems to be favourable, and therefore substantiated knowledge of molecular and cellular mechanisms in nerve sheath tumors should be achieved. Here, we firstly describe the expression of the chemokines CXCL12 (SDF-1) and CX3CL1 (fractalkine) and their respective receptors CXCR4, CXCR7 and CX3CR1 in different entities of human nerve sheath tumors and normal control tissues. Both ligands and their receptors are expressed in high to moderate levels on mRNA and protein level in benign and malignant nerve sheath tumors. While CXCL12 was mainly found in schwannoma cells (S100⁺) in situ, its receptor CXCR4 is also partly found on CD11b-positive macrophages / microglia and its alternative receptor CXCR7 is also expressed by endothelial cells and macrophages. CX3CL1 is expressed by parts of the schwannoma and endothelial cells, whereas its receptor CX3CR1 is expressed by nearly all tumor cells and macrophages, but not by endothelial cells. Taken together, we could show the presence of CXCL12 and CX3CL1 and their respective receptors in benign and malignant human nerve sheath tumors. Further investigations may show their functional role in health and disease.

The expression of mismatch repair proteins MLH1, MSH2 and MSH6 correlates with the Ki67 proliferation index and survival in patients with recurrent glioblastoma.

OBJECTIVES: There is a growing body of evidence that deficiency of DNA mismatch repair proteins other than O(6)-methylguanine-DNA methyltransferase (MGMT) also contributes to glioblastoma recurrence. We examined the protein expression of MLH1, MSH2 and MSH6 in paired initial and recurrent glioblastoma and compared the results to the Ki67 proliferation index and patient survival. METHODS: Forty-two patients were included who met the following inclusion criteria: (1) histologically confirmed primary glioblastoma; (2) total tumour resection at initial craniotomy; (3) re-craniotomy for recurrence. Immunohistochemical staining was performed using specific monoclonal antibodies against MLH1, MSH2, MSH6 and Ki67. Chi-square test, Wilcoxon test and log-rank test (Cox-Mantel) were used for statistical analysis. RESULTS: In recurrent tumours, MLH1 expression was significantly reduced. MLH1, MSH2 and MSH6 expression in initial lesions was significantly associated with the Ki67 proliferation index. MLH1 and MSH2 expression in recurrent lesions was also significantly associated with the Ki67 proliferation index. MLH1 and MSH6 positivities in initial lesions were indicators of reduced patient survival. DISCUSSION: Our results indicate a potential important role of MLH1 and MSH6 in glioblastoma progression. Specific attention should be given on the role of MLH1 and MSH6 in patients with glioblastoma recurrence during temozolomide treatment.

Glioblastoma of the cerebellum and brainstem.

Glioblastoma multiforme (GB) is the most common and most malignant primary intracranial tumor. Of the 577 patients who underwent surgery for newly diagnosed GB (World Health Organization grade IV) between January 1991 and March 2008 at our department, seven had infratentorial GB (iGB) (incidence 1.2%). Patients younger than 21years of age, as well as patients with gliomatosis cerebri, were excluded from the analysis. We concluded that iGB is rare in adults. Because of its rarity and the non-specific radiological features of iGB, it can easily be misdiagnosed as a brain metastasis, ependymoma or even as a benign lesion such as vestibular schwannoma or meningioma. Surgical removal, or at least stereotactic biopsy, is essential to establish the diagnosis. Postoperative adjuvant therapy similar to that for supratentorial glioblastoma is indicated. We analysed the clinical characteristics and therapy of our patients with iGB and reviewed the literature.

A case of rapid-growing anaplastic meningiomas.

Meningiomas are tumours originating from the leptomeningeal covering of the brain and spinal cord and are generally benign and slow growing. Rarely, they show malignant anaplastic characteristics with a high recurrence rate. A number of factors have been reported to predict this high recurrence. Such factors are histopathological ones, such as necrosis and hypercellularity, the World Health Organization (WHO) grade, mitotic index, positivity of proliferation markers (Ki-67 or MIB-1), clinical parameters such as age, gender, localisation, cytogenetic factors and radiation treatment. The present case reports a patient with a giant meningioma over the right frontal lobe who had almost all possible negative prognostic parameters and showed an explosive multifocal recurrence in a timespan of about 5 months.

Overexpression of CXCL16 and its receptor CXCR6/Bonzo promotes growth of human schwannomas.

Chemokines and their receptors play a decisive role in tumor progression and metastasis. Here, we describe the expression of the CXCL16-CXCR6-system in human schwannomas of different localization and in malignant peripheral nerve sheath tumors. The transmembrane chemokine CXCL16 and its receptor CXCR6/Bonzo were overexpressed on the mRNA and protein levels in all tumor samples investigated as compared with normal peripheral or 8th cranial nerve tissues. Chromogenic immunostaining and confocal laser microscopy revealed that CXCL16 and CXCR6 were localized mainly on S-100 positive schwannoma cells. Cultured schwannoma cells responded to CXCL16-stimulation by phosphorylation of kinases p42/44 (Erk 2/1) that could be inhibited by the MEK1/2-inhibitor U0126 indicating an involvement of the mitogen-activated protein kinase signal transduction pathway. As a biological response, CXCL16 increased proliferation and induced migration of schwannomas. Hence, CXCL16 appears to be a novel growth factor for schwannomas of different localization.

Overexpression of midkine contributes to anti-apoptotic effects in human meningiomas.

Meningiomas are the second most common intracranial tumours. Most meningiomas grow slowly; however, atypical and anaplastic meningiomas show an aggressive biological behaviour. Overexpression of growth factors is considered to be a cause of carcinogenesis. Midkine and pleiotrophin are heparin-binding growth factors that promote growth, survival, migration and differentiation of various target cells. Both molecules are highly expressed during human embryogenesis but are rarely seen in the adult. We show that in relation to normal dura and arachnoid tissues, midkine was overexpressed in meningiomas on the mRNA and protein level, whereas pleiotrophin was not. Thereby, not only the intact but also the truncated form of midkine could be observed. The expression of midkine receptors was variable in different samples. Midkine stimulation of cultured meningioma cells induced phosphorylation of Akt, whereas no increase in phosphorylation of p42/44 MAPK or p38 MAPK could be detected. Midkine did not influence the proliferation of meningioma cells in vitro, but it did protect meningioma cells from camptothecin-mediated apoptotic cell death through reduction in the amounts of active caspase-3. These findings provide evidence for the overexpression of midkine in meningiomas which contributes to protection from cell death in these second most common intracranial tumours.

Protein expression of Fas, Fas ligand, Bcl-2 and TGFbeta2 and correlation with survival in initial and recurrent human gliomas.

Several studies have recently demonstrated that human gliomas express Fas, Fas ligand (FasL), Bcl-2 and TGFbeta2 at some degree. These factors are considered to interact with apoptotic processes and to have immuno-reactive potential. Their role for tumor evasion from the immune surveillance is currently under examination. To date, there is only limited information about the definite expression patterns of these four factors in human gliomas, particularly in pilocytic astrocytoma (PA) and recurrent tumors. We analyzed 75 human gliomas for the immunohistochemical expression of Fas, FasL, Bcl-2, and TGFbeta2: (1) 25 PAs (WHO grade I), (2) 25 primary glioblastomas (WHO grade IV), and (3) 25 paired initial and recurrent glioblastomas (WHO grade IV), respectively. Co-expression of all four factors was present in the majority of specimens, i.e. in 72% (18/25) of PAs and 88% (47/50) of primary glioblastomas. Pilocytic astrocytomas showed significantly higher scores of TGFbeta2 expression (p < 0.05) and significantly lower Fas, Fas ligand and Bcl-2 scores (p < 0.05) than glioblastomas. There were no significant expression differences in initial versus recurrent glioblastoma specimens. Likewise, no significant correlation was observed between protein expression and clinical parameters, i.e. total survival time or progression free survival time, as documented by Kaplan-Meier method and log rank-test. In conclusion, Fas, FasL, Bcl-2 and TGFbeta2 are differently expressed in PAs versus glioblastomas. These factors, however, are not associated with patient prognosis. The broad co-expression of these factors may enable new therapeutic approaches in the future.

Clinical experiences with oligoastrocytomas WHO grade II and III.

Between April 1991 and June 2002, 39 patients with an histologically proven oligoastrocytoma WHO grade II and III were operated on in our department. Twenty-two patients were male and 17 female. Mean age was 42 years (20-67 years). The tumor was localized in the frontal lobe in 22 patients, in the temporal lobe in seven patients, in the parietal lobe in nine patients and in the occipital lobe in one patient. The leading clinical symptoms were seizures in 33 patients. Seventeen patients were operated on under local anesthesia. One operation was performed in 22 patients, two operations in eight, three operations in five, four operations in three and six operations in one patient. Histological examination showed oligoastrocytoma WHO grade II in 12 patients and WHO grade III in 27 patients. Postoperative radiotherapy was performed in 33 patients and chemotherapy in six patients. One female patient developed spinal drop metastases 10 months after the operation. One patient with a primary oligoastrocytoma grade II and five patients with a primary oligoastrocytoma grade III died during follow-up. The follow-up period was between 6 months and 25 years (mean 7 years 6 months).