Immunobiological and experimental aspects of malignant astrocytoma.

Today several findings indicate that a multifactorial strategy is the best strategy for treating cancer. Although radiotherapy, chemotherapy and surgery have been differently applied to treat human gliomas, no substantial improvement in life expectancy has been observed. Starting from 1992, the goal of our studies was to obtain new biological data on malignant astrocytomas to better understand the basic biology of the tumour and these are reviewed here. Immunotherapy may represent an available method in addition to the traditional therapeutic approaches. Starting from 1991, we set up a cellular model of lymphocytes obtained from peripheral blood of healthy patients treated with interleukin-2 (IL-2) in order to study the role of IL-2 in regulating lymphocytes activation. The lymphocytes responding to IL-2 treatment, named lymphokine-activated killer (LAK) cells, have a killer non MHC restricted activity, and are able to kill autologous and allogenic glioma cells. The interaction of LAK cells with various normal and transformed targets indicates that LAK cells recognize surface structures present both on normal and transformed cells. However, only the interaction with transformed cells induces lytic events and LAK cells can act as "surgical weapons" against tumour cells independently from their cell cycle. Much recent effort has focused on identifying the immune escape mechanisms used by glioma cells, in particular the modulation of the human leukocyte antigen (HLA) and antigen processing machinery component expression. Finally, another interesting field of research that will be presented is that of new tumour biomarkers of proliferation and apoptosis, cytokine/chemokine release and cytokine/chemokine receptors.

Endoscopic removal of a central neurocytoma from the posterior third ventricle.

Central neurocytoma is a rare benign tumor that most commonly arises within the ventricular system of young adults. Its occurrence in the posterior third ventricle is one of the least reported presentations. These tumors are usually treated by a combination of either biopsy or open surgical resection, often followed by radiation (Gamma knife or Novalis) with or without chemotherapy. A 37-year-old woman with a posterior third ventricle neurocytoma presented with acute signs of aqueductal stenosis. The patient underwent endoscopic assisted gross total resection of the tumor with the aid of intraoperative laser followed by standard third ventriculostomy; no further treatment was required. The patient did not develop any subsequent neurological deficit. A 36-month follow-up was still consistent with a normal neurological examination. Serial post-operative MRIs show neither residual nor recurrent tumor. Thus, posterior third ventricle central neurocytomas are relatively benign tumors that can be successfully removed using a minimally invasive approach, thereby avoiding both the morbidity related to conventional open craniotomy and the potential toxicity of any adjuvant treatment.

Exogenous platelet-derived growth factor (PDGF) induces human astrocytoma cell line proliferation.

Platelet-derived growth factor receptors (PDGFR) regulate several processes in normal cells including cellular proliferation, differentiation and migration, and are widely expressed in a variety of malignancies. In astrocytoma, PDGF ligand and receptor are often overexpressed and PDGFR activity deregulation has been linked to pathogenesis. The issue of the functional capacity of PDGFR has only occasionally been addressed in glioma cells by measuring the proliferative response induced by exogenous PDGF. In the present study, PDGFRalpha expression was evaluated in human grade 2 and 4 astrocytoma cell lines and tissue specimens by immunocytochemistry. The receptor responsiveness to exogenous PDGF was determined in astrocytoma cells with an MTT assay. It was found that astrocytoma cells express PDGFRalpha and respond to PDGF mitogenic action in a grade-dependent manner. The receptor was found to be functional since it induced cell proliferation at different ligand concentrations. We can thus conclude that the proliferative response of human astrocytoma cells is related to their malignancy and receptor status before PDGF stimulation, suggesting a role for PDGFRalpha inhibitors as blockers of malignant cell proliferation.

Diagnostic value of PRND gene expression profiles in astrocytomas: relationship to tumor grades of malignancy.

Doppel (PRND) is a paralogue of the mammalian prion (PRNP) gene. It is abundant in testis and, unlike PRNP, it is expressed at low levels in the adult central nervous system (CNS). Besides, doppel overexpression correlates with some prion-disease pathological features, such as ataxia and death of cerebellar neurons. Recently, ectopic expression of doppel was found in two different tumor types, specifically in glial and haematological cancers. In order to address clinical important issues, PRND mRNA expression was investigated in a panel of 111 astrocytoma tissue samples, histologically classified according to the World Health Organization (WHO) criteria (6 grade I pilocytic astrocytomas, 15 grade II low-grade astrocytomas, 26 grade III anaplastic astrocytomas and 64 grade IV glioblastoma multiforme). Real-time PRND gene expression profiling, after normalisation with GAPDH, revealed large differences between low (WHO I and II) and high grade (III and IV) of malignancy (P<0.001). Extensive differences in PRND gene expression were also found within each grade of malignancy, suggesting that PRND mRNA quantitation might be useful to distinguish astrocytoma subtypes, and important in disease stratification and in the assessment of specific treatment strategies.

Immunohistochemical evaluation of minichromosome maintenance protein 7 in astrocytoma grading.

The minichromosome maintenance (MCM) proteins, which play an important role in eukaryotic DNA replication, represent a group of proteins that are currently under investigation as novel diagnostic tumor markers. Several studies have proved a greater reliability of MCM proteins to stain proliferating cells compared to Ki67 protein, a routinely used proliferation marker in histopathology. In the present study, the expressions of MCM7 and Ki67 were estimated in 66 primary human astrocytomas in relation to tumor grade (Grade I-IV, WHO). MCM7 significantly stained more nuclei compared to Ki67 in all the histopathological grades investigated. In addition, a stronger increase of the MCM7 labelling index, in relation to the tumor aggressiveness, was observed.

A randomized phase III study: comparison between intravenous and intraarterial ACNU administration in newly diagnosed primary glioblastomas.

BACKGROUND: In this randomized phase III study, the effectiveness as well as the side-effects of intraarterial [i.a.] (17 patients) versus intravenous [i.v.] (16 patients) ACNU [Nimustine] administration in newly diagnosed glioblastoma, were compared. PATIENTS AND METHODS: All patients undenwent extensive surgical resection, and both groups were homogeneous for the other known risk factors. Thirty-three patients with glioblastoma were treated with ACNU at the dose of 80-100 mg/m2. Treatment was repeated every 5-8 weeks for a minimum of 2 and maximum of 14 cycles. Total survival time (TST) and to time to progression were chosen as outcome variables. RESULTS AND CONCLUSION: No significant differences in systemic and hematological toxicity between the i.a. and iv. ACNU administration routes were detected. In both groups, tolerance of the procedure was excellent. Analysis of the main outcome measured showed no significant differences between i.a. and i.v. ACNU administration: time to progression was 6 months for i.a. ACNU and 4 months for i.v. ACNU and total survival time was 17 months for i.a. ACNU and 20 months for i.v. ACNU. In spite of ACNU dose incrementation, obtained through i.a. route administration, and subsequent higher concentration in the tumor bed, no improvement could be achieved in effectiveness.

Carotid cavernous aneurysm presenting as pituitary apoplexy.

The authors report an interesting case with a ruptured internal carotid artery aneurysm that presented as a sellar haematoma mimicking radiologically a pituitary adenoma, and clinically a pituitary apoplexy. A 53-year-old woman presented with a 2-week history of episodic severe headache and vomiting associated, 3 days prior to admission, with left ophthalmoparesis and transient right hemiparesis. Brain MRI showed a large intra- and suprasellar mass suggestive of a pituitary macroadenoma. Hormonal profiles showed hyperprolactinaemia and subsequent cerebral angiography demonstrated a carotid cavernous aneurysm. The patient underwent surgery via a subfrontal approach to manage both lesions. At operation, the suspected pituitary adenoma was revealed to be a sellar haematoma; the aneurysm was successfully clipped. Postoperatively, the patient developed hypotension and right hemiparesis which, as well as the third nerve paresis, progressively improved to full recovery. At 12 months follow-up the patient is neurologically intact and generally well. The clinical features, the management of such a case and the importance of differential diagnosis in the acute stage are emphasised and discussed along with relevant literature.

Minichromosome maintenance protein 7: a reliable tool for glioblastoma proliferation index.

At present there is increasing evidence concerning the value of minichromosome maintenance (MCM) protein expression as a novel indicator of proliferation. In the present study, 15 glioblastoma samples, classified according to WHO, were analysed to evaluate the expression of the principal proliferation markers. The samples examined were subdivided into 2 cytological subsets, small cell (SC) or multiforme cell (MC) glioblastoma, according to the predominant cell type defined in individual specimens. MCM7 detected more cells in the cycle than Ki67 and PCNA and all cases of SC glioblastoma, the most aggressive subset, displayed a significant increase of MCM7-stained nuclei versus those stained with Ki67. These results suggest that the cell cycle-associated proteins MCM are not only useful markers of proliferation, but also valid aids for diagnosis in cerebral glioblastoma.

Brain tissue autofluorescence: an aid for intraoperative delineation of tumor resection margins.

The intrinsic autofluorescence properties of biological tissues can change depending on alterations induced by pathological processes. Evidence has been reported concerning the application of autofluorescence as a parameter for in situ cancer detection in several organs. In this paper, autofluorescence properties of normal and tumor tissue in the brain are described, suitable for a real-time diagnostic application. Data were obtained both on ex vivo resected samples, by microspectrofluorometric techniques, and in vivo, during surgical operation, by means of fiberoptic probe. Significant differences were found in autofluorescence emission properties between normal and tumor tissues, in terms of both spectral shape and signal amplitude, that confirm the potential of autofluorescence as a parameter to distinguish neoplastic from normal condition. The noninvasiveness of the technique opens up interesting prospects for improving the efficacy of neurosurgical operations, by allowing an intraoperative delineation of tumor resection margins.

Activated lymphocytes in glioblastoma: significance for anti-tumoral immunity.

Interaction between immune cells and tumoral cells of a case of glioblastoma was studied. Tissue fragments obtained during neurosurgery from different areas of the tumor were examined before and after rIL-2 treatment in vitro. The same morphofunctional type of cells usually activated by rIL-2, which show antitumoral reactivity, was observed both in the glioblastoma imprints and in tumoral fragments cultured with rIL-2. This cytokine stimulated the proliferation of tumor infiltrating lymphocytes in vitro. This preliminary study shows that IL-2 potentiates the differentiation of HMS cells in peripheral blood which probably pass through the blood brain barrier and infiltrate the tumor.

Long-term follow-up in 257 ICA occlusion: comparison between EIAB-treated and untreated patients.

The purpose of this paper is to estimate the real value of the Extra-Intracranial Arterial Bypass (EIAB) in preventing or reducing further and more catastrophic ischaemic events in patients suffering from an Internal Carotid Artery (ICA) occlusion. 257 patients, suffering from ICA occlusion, are considered retrospectively: 122 of them submitted to EIAB and 135 medically treated or untreated. In both groups, homogeneous by sex, age, neurological grading distribution and length of follow-up, the following parameters were considered: the incidence of ischaemic recurrences during the follow-up period; the characters of the recurrences with particular reference to the fatal stroke; the rate of ischaemic events per year. The comparison between the outcome in surgically treated patients and in "untreated" ones indicates that the EIAB can be effective in preventing or reducing the ischaemic recurrences and the frequency of fatal stroke in TIA-, RIND, or stroke-patients suffering from ICA occlusion.

Extra-intracranial arterial bypass in typical carotid reversible ischaemic deficits: long-term follow-up in 100 patients.

The long-term follow-up of 100 consecutive patients who suffered from a reversible ischaemic attack (RIA) in the carotid territory and were submitted to extra-intracranial arterial bypass (EIAB) surgery in seven Italian Neurosurgical Centres is reported. The preoperative angiographic and clinical features, and the surgical complications are reported. The follow-up ranged from two to seven years with a mean of thirty-five months. In this period in the territory served by the bypass only two completed strokes and six RIAs occurred. Four patients died, only one for cerebral ischaemic problems. The results of the present series have been compared with those of the literature: they appeared consistent with other surgical series and clearly better than those of medical treated patients. The EIAB can then be considered a good therapeutic choice for the treatment of RIAs in carotid territory.