Heinz-Hermann Hugo

Expression of Somatostatin Receptor Subtypes in Cultured Astrocytes and Gliomas

Abstract: Expression of receptors for the neuropeptide somatostatin was investigated in vitro in rat and human astrocytes, glioma cell lines, and solid human glial tumors that were all immunopositive for the astrocytic marker glial fibrillary acidic protein. After affinity labelling with a peptide‐gold conjugate of known biological activity, somatostatin‐binding sites could be visualized at the light‐ and electron‐microscopic level on the surface of glial cells. Glioma cells were generally labeled more strongly than were normal astrocytes and preferentially bound the ligand at their processes and not at their somata as were normal cells. Somatostatin transmembrane receptor (SSTR) subtype expression was probed by reverse transcription‐polymerase chain reaction: In rat and human cortical astrocytes and in one glioma cell line (U 118), a pattern of three subtypes (SSTR‐1, SSTR‐2, and SSTR‐4) was detected, whereas, in all other glioma cell lines and in six solid glial tumors investigated, the SSTR‐2 subtype was relatively stronger, expressed either alone or in combination with SSTR‐1; sometimes SSTR‐3 or SSTR‐4 was demonstrated in clearly reduced amounts. In astrocytes and gliomas, somatostatin reduced the levels of cyclic AMP elicited by the adenylate cyclase activator forskolin indicating that at least one of the receptor subtypes is negatively linked to adenylate cyclase. In contrast to other cell types, somatostatin did not inhibit the basal or the fetal calf serum‐stimulated proliferation of astrocytes, glioma cell lines, or glial tumors in culture. Thus, strong SSTR‐2 subtype expression characterizes glial tumors, but somatostatin is ineffective in inhibiting their growth.

Malignant peripheral nerve sheath tumours--report of 8 cases and review of the literature.

Summary Background. Though Malignant peripheral nerve sheath tumours (MPNST) are a rare entity accounting for 5–10% of soft-tissue sarcomas they are an important differential diagnosis to benign tumours of the peripheral nervous system regarding treatment and prognosis. Method. We present our experience with eight patients who underwent surgery for MPNST at the Department of Neurosurgery between 10/1990 and 9/1999. The median age was 37 years [range: 13–64], the male/female ratio was 1:1. Two patients suffered from Neurofibromatosis type 1. Paraffin embedded tumour specimens were immunohistochemically stained for S-100, p53 and Ki67/MIB-1. Findings. The most frequent initial symptoms were local swelling and pain followed by irritation of cranial nerves and spinal ataxia. Four tumours were localised at the head & neck region, three were found in the extremities and one tumour was located on the trunk. All patients underwent surgery with curative intent, but total resection, defined by negative surgical margins, was achieved in only 3 cases. All of these developed local recurrence with a mean disease free survival time of 10,6 months. In five cases, adjuvant radiation was given. During follow up, three patients developed distant metastases located in the lung, liver and subcutaneous tissue. Five out of eight patients died during follow-up with a mean survival time of 11,6 months after diagnosis. Results of immunohistochemical staining were as followed: S-100 (7/8), p53 (7/8). The Ki67/MIB-1 proliferation index was detectable in all tumour samples, it differed from 10–30%. Interpretation. MPNST is a rare and fatal diagnosis in neurosurgery with high risk of local recurrence and occurence of distant metastases. Though mulitimodal therapy including surgical resection and adjuvant radiotherapy including brachytherapy is available, the prognosis remains dismal. Modern clinical studies and the development of effective chemotherapy is needed in order to gain control of the disease.

Spontaneous intracranial haematomas caused by neoplasms.

Summary¶ We report about 50 patients with spontaneous intracerebral haematomas (ICH) caused by intracranial neoplasms to assess the underlying histological condition, their presentation on admission, diagnostic work-up, treatment, histological diagnosis, and clinical outcome. These patients were identified in a prospective series of 2041 patients with intracranial neoplasms and 692 patients with spontaneous ICH, which were both consecutively collected over a nine-year-period. The frequency of ICH in patients with intracranial neoplasms was 2.4%. The frequency of tumour related ICH in the ICH group was 7.2%. The leading cause of tumour related ICH were metastases of extracranial origin (n=18; 36%), followed by glioblastoma multiforme (n=15; 30%). Nine patients (18%) had benign primary intracranial neoplasms. On admission 18 patients were somnolent (36%) and 14 patients (28%) were comatose. In 29 cases (58%) ICH was the first clinical sign of neoplastic disease, while in 21 patients (42%) a malignant tumour was already known. We operated on 45 patients (90%), four patients (8%) were not operated on because of poor clinical condition and died, one patient refused surgical treatment. Six patients (12%) died despite surgery. This series confirms the importance of a proper neuroradiological and clinical work-up of patients with suspected tumour related ICH followed by operative treatment and histological confirmation of the diagnosis. This is supported by the fact that 18% of patients had prognostically favourable intracranial tumours which would not otherwise have been adequately treated.

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.

Spinal Drop Metastases in Recurrent Glioblastoma Multiforme

Summary Multifocal dissemination of glioblastomas is very rare but is increasing as patients live longer. Between April 1994 and December 1997 one hundred and fifty one patients with a histologically proven glioblastoma multiforme were operated on in the Neurosurgical Department of the University of Kiel, Germany. Recurrent tumours of these patients were removed in 36 patients. Two patients developed multifocal spread of glioblastoma multiforme including spinal drop metastases. Both patients died 10 and 7 months after the primary operation. On histological examination both tumours showed wide perivascular tumour-cell cuffings in the surrounding brain tissue, so that this perivascular growth might be another explanation for the dissemination in these glioblastomas.

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

Abstract Objectives: There is a growing body of evidence that deficiency of DNA mismatch repair proteins other than O6-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.

Protein Expression of Fas, Fas Ligand, Bcl-2 and TGFβ2 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 TGFβ2 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 TGFβ2: (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 TGFβ2 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 TGFβ2 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.

Granular-cell tumour: a rare suprasellar mass.

Abstract Granular-cell tumour is a rare suprasellar space occupying lesion, which usually presents with visual deterioration, endocrine deficits or headache. We present two women with extraordinarily large tumours, measuring 3.8 and 4.0 cm in diameter. In both cases the tough, vascular tumour could be removed only subtotally.

Secretory Meningiomas: Clinical and Immunohistochemical Observations

OBJECTIVESecretory meningiomas are a rare histological subtype of these benign intracranial tumors. Few reports have been published regarding their tendency to develop peritumoral edema. METHODSBetween July 1994 and February 1999, 11 patients with secretory meningiomas underwent operations in the Department of Neurosurgery, University of Kiel, Kiel, Germany. The clinical notes and radiological data (computed tomographic and magnetic resonance imaging scans) were reviewed. Immunohistochemistry was used to examine the expression of carcinoembryonic antigen and epithelial membrane antigen as well as progesterone and estrogen receptors. RESULTSSecretory meningiomas were found in 11 (5%) of 214 patients with intracranial meningiomas who were operated on in that period. All 11 patients were women. These patients’ mean age was 65 years (range, 51–87 yr). The localization of these tumors was at the convexity in seven patients, at the sphenoid ridge in two patients, and in the olfactory groove and petroclival region in one patient each. Two meningiomas had no edema surrounding them, two meningiomas had a small amount of edema, two had moderate edema, and five had severe edema. No recurrences were observed during the mean follow-up period of 26 months (range, 8–65 mo). Immunohistochemically, all tumors contained pseudopsammoma bodies and reacted with epithelial membrane antigen and carcinoembryonic antigen. The MIB-1 antibody staining index showed a mean of 2% (range, 0–7%). CONCLUSIONSecretory meningiomas are rare tumors, and they are mainly localized at the frontal convexity and the sphenoid ridge. They are surrounded by more edema than usual. The preponderance of female patients with this presentation is striking. The expression of carcinoembryonic antigen and epithelial membrane antigen is a characteristic feature of secretory meningiomas. These meningiomas are also positive for progesterone receptors, which has been shown to be a good prognostic factor.