Franco Ammannati

Screening for mutations in the neurofibromatosis type 2 (NF2) gene in sporadic meningiomas

Meningiomas are benign tumors of the central nervous system. They are usually sporadic but can also occur associated with the neurofibromatosis type 2 (NF2) syndrome. The gene responsible for NF2, recently isolated from chromosome 22, encodes a membrane-organizing protein that shows high sequence homology to a protein family thought to link the cytoskeleton with membrane proteins. Mutations of the NF2 gene have been described in sporadic meningiomas, exclusively in tumors that show loss of heterozygosity (LOH) of 22q. These preliminary results indicate that the NF2 gene is involved in the pathogenesis of at least a subset of meningiomas, where it does indeed behave as a tumor suppressor gene. In order to characterize better the role of the NF2 gene in the genesis of meningiomas we have examined the entire coding sequence of the gene in 125 meningiomas by single-strand conformational polymorphism analysis; furthermore, LOH analysis for markers of 22q has been carried out. Inactivating mutations were identified in 30% of our samples, all of which also showed LOH of 22q. The majority of mutations identified were frameshifts and nonsense mutations, which are predicted to produce a truncated or non-functional protein. We also found two missense and three in-frame deletions that may pinpoint specific regions of the protein critical to its function. Furthermore, the distribution of mutations throughout the gene, suggested that exons 2, 3, 5, 11 and 13 are more frequently involved. Our results reconfirm the importance of the NF2 gene in the pathogenesis of meningiomas and also suggest that there may be a nonrandom clustering of mutations throughout the gene.

Somatic mutations in the neurofibromatosis type 2 gene in sporadic meningiomas

Meningiomas are benign tumors of the central nervous system. Although usually sporadic, they can occur in patients affected by the autosomal dominant syndrome, neurofibromatosis type 2 (NF2). The NF2 gene has recently been isolated from chromosome 22. The presence of germline mutations in NF2 patients and the loss of heterozygosity (LOH) on 22q in NF2 tumors support the hypothesis that the NF2 gene acts as a tumor suppressor. Cytogenetic and LOH studies have suggested that the gene responsible for the development of meningiomas is located in the region of 22q in which the NF2 gene maps. The meningioma gene could therefore be the NF2 gene itself. Recently, somatic mutations of the NF2 gene have been identified in sporadic meningiomas, thus supporting the hypothesis that the NF2 gene is also important in meningioma pathogenesis. In this study, we analyzed sixty-one sporadic meningiomas for LOH of 22q and for mutations in the NF2 gene. LOH was detected in 36 of the 60 informative tumors. Single-strand conformational polymorphism analysis was used to identify nine mutations in five of the eight exons of the NF2 gene studied. The nine tumors with an altered NF2 gene also showed LOH for 22q markers. These results further support the hypothesis that mutations in the NF2 gene are a critical pathogenetic event in at least some meningiomas.

Second-line chemotherapy with fotemustine in temozolomide-pretreated patients with relapsing glioblastoma: a single institution experience.

To evaluate efficacy and safety of fotemustine chemotherapy in temozolomide (TMZ) pretreated adults with recurrent glioblastoma multiforme (GBM). Primary endpoint was progression-free survival at 6 months. Twenty-seven patients (median age: 56 years; median Karnofsky performance status at progression: 80) with relapsed glioblastoma multiforme underwent fotemustine as second-line chemotherapy after failure of homogeneous postoperative treatment consisting of conformal radiotherapy (60 Gy in 30 fractions) with concomitant TMZ (75 mg/m2 per day), followed by six courses of TMZ (150–200 mg/m2 for 5 days every 28 days). Patients were assigned to Radiation Therapy Oncology Group recursive partitioning analysis classes for gliomas. After MRI-proven tumor relapse or progression, all patients underwent chemotherapy with fotemustine, given intravenously 100 mg/m2 every week for 3 consecutive weeks (induction phase) and then every 3 weeks (maintenance phase). Adequate liver, renal, and bone marrow functions were required. Toxicity grading was based on the National Cancer Institutes Common Toxicity Criteria (version 2.0). Response to treatment was assessed on MacDonald criteria. According to an intention-to-treat-analysis, data on all enrolled patients were included in statistical analysis. Eight partial responses (29.6%) and five cases of stable disease (18.5%) were observed. Median time to progression was 5.7 months. Progression-free survival at 6 months was 48.15%. Median survival from the beginning of fotemustine chemotherapy was 9.1 months. Median survival from diagnosis of glioblastoma was 21.2 months. Toxicity was manageable and mainly hematological (grade 3 thrombocytopenia: three cases; grade 4 leukopenia: one case). Fotemustine has shown therapeutic efficacy as single-drug second-line chemotherapy in treatment of TMZ pretreated patients.

Genetic insights into familial tumors of the nervous system.

Nervous system tumors represent unique neoplasms that arise within the central and peripheral nervous system. While the vast majority of nervous system neoplasm occur sporadically, most of the adult and pediatric forms have a hereditary equivalent. In a little over a decade, we have seen a tremendous increase in knowledge of the primary genetic basis of many of the familial cancer syndromes that involve the nervous system, syndromes that are mostly inherited as autosomal dominant traits. In this review, we discuss the most recent findings on the genetic basis of hereditary nervous system tumors. The identification of genes associated with familial cancer syndromes has in some families enabled a “molecular diagnosis” that complements clinical assessment and allows directed cancer surveillance for those individuals determined to be at‐risk for disease.

Evaluation of the anterior pituitary function in the acute phase after spontaneous subarachnoid hemorrhage

Background: Subarachnoid hemorrhage (SAH) is a potential cause of hypopituitarism. Most of the studies regarding the relationship between SAH and anterior pituitary function were retrospective and hormonal assessment was performed several months after SAH. Aim: To prospectively evaluate the prevalence of anterior pituitary hormone deficiencies in the acute phase after spontaneous SAH and their possible correlation with clinical and radiological parameters. Methods: Pituitary function was tested in 60 patients within 72 h after spontaneous SAH. Results: 56.9% of the patients showed at least one anterior pituitary hormone deficiency: gonadotropin and GH secretion failure represented the most prevalent hormonal deficiencies (33.3 and 22.0%, respectively), whereas ACTH and TSH deficiency was less frequent (7.1 and 1.8%, respectively). With the exception of secondary hypogonadism, the prevalence of other pituitary hormone deficiencies is in agreement with previous studies, which evaluated pituitary function on long-term follow up after SAH. No correlation was found between hypopituitarism and clinical status, as assessed with Hunt-Hess and Glascow Coma Scales. Moreover, no correlation was found between hypopituitarism and bleeding severity evaluated with Fisher’s scale. Conclusions: We demonstrated a high prevalence of anterior pituitary hormone deficiencies acutely after SAH. Although part of GH and gonadotropin deficiencies might be a consequence of functional alteration due to SAH itself, the finding of low cortisol levels in this stressful condition strongly suggests the presence of true hypocortisolism. Therefore, an evaluation of pituitary function shortly after SAH might be useful to identify a subset of patients who deserve a more accurate follow-up.

Which target for DBS in Parkinson's disease? Subthalamic nucleus versus globus pallidus internus.

Abstract We selected 14 patients with advanced idiopathic Parkinsons disease (PD) and examined the clinical effects of STN DBS versus GPi DBS. Nine patients underwent bilateral STN DBS and five underwent bilateral GPi patients. All patients were followed for at least 12 months. The evaluation was performed on and off drug before surgery; on-drug/on-DBS and off-drug/on-DBS at 1, 2, 6 and 12 months after stereotactic surgery. At 1 and 3 months after surgery in off-drug/on-DBS condition, both groups showed an improvement in motor score (UPDRS II). Nevertheless, the results changed after long-term stimulation in the two groups. Chronic STN DBS is superior to GPi DBS in the amelioration of the clinical features and in the decrease of time spent in the off state. The efficacy in reduction of LID was comparable at 1 and 3 months after surgery, but the results were better in STN DBS after chronic stimulation. The L-dopa dose was reduced only in the STN group.

Analysis of the neurofibromatosis type 2 gene in different human tumors of neuroectodermal origin

The autosomal dominant syndrome neurofibromatosis type 2 (NF2) is characterized by the development of bilateral vestibular schwannomas, meningiomas, ependymomas and gliomas. The NF2 gene, recently isolated from chromosome 22, is mutated in both sporadic and NF2 tumors such as schwannomas, meningiomas and ependymomas. Mutations of the gene have been described not only in the neoplasms usually associated with NF2, but also in 30% of the melanomas and 41 % of the mesotheliomas analyzed. In particular, the finding of mutations in melanomas supports the hypothesis that the NF2 gene is involved in the genesis of several tumor types that arise from the embryonic neural crest. In this study we examined, by single-strand conformation polymorphism (SSCP) analysis, 41 tumors of the central nervous system (11 schwannomas and 30 gliomas), 19 melanomas and 15 Merkel cell carcinoma specimens for mutations in the coding sequence of the NF2 gene. We found three inactivating mutations of the NF2 gene in schwannomas. No alterations of the gene were detected by SSCP analysis of the other tumors. These results confirm the role of NF2 in pathogenesis of schwannomas, but do not define its significance in the genesis of the other neuroectodermal tumors studied.

Extraventricular neurocytoma: morphological and immunohistochemical considerations on differential diagnosis.

Neurocytoma is an unusual neuronal tumor especially affecting young people. It commonly arises in the ventricles and has a benign outcome. Herein, we report on a rare case of extraventricular neurocytomas (right parietal lobe) in a young girl admitted to hospital for a cranial trauma subsequent to a seizure. The tumor, radiologically well-circumscribed, cystic and enhancing, was surgically excised. The patient, who received no post surgical treatment, is alive and well after 18 months of follow-up. Pathological examination showed a well-differentiated lesion composed of uniform, round cells with perinuclear halos in a neuropil background and immunohistochemically positive for neuronal markers (synaptophysin, neuron-specific enolase, neurofilaments). The authors emphasize the role of the morphological and immunohistochemical evaluations to recognize this rare tumor.

NF2 gene expression in sporadic meningiomas: Relation to grades or histotypes real time-PCR study

One of the most common regions involved in the meningiomas tumorigenesis is chromosome 22q where the NF2 gene resides. The deficiency or loss of the NF2 gene product, merlin/schwannomin, plays a role in tumor development and metastatization. Conflicting results have been reported on the prognostic value of merlin in meningiomas. Several studies have indicated NF2 gene inactivation as an early tumorigenic event unrelated to the histological grade or clinical behavior. On the contrary, the NF2 gene alteration rate differs between the different histotypes. A pathogenesis independent from the NF2 gene has been suggested in meningothelial meningiomas. In the present work, we studied the NF2 gene expression through real time‐PCR (RT‐PCR) in 30 meningiomas. The average of the NF2 gene expression of all meningiomas was considered as reference value. The average of expression of WHO grade I and II meningiomas was higher than the average of all meningiomas, whereas that of WHO grade III meningiomas was lower. When we compared the NF2 gene expression in the different meningioma grades we did not note a significant difference (P = 0.698) despite the tendency to decrease from grade I to grade III. The average expression of meningothelial meningiomas was higher than the reference value, and that of non‐meningothelial meningiomas was lower. The difference in NF2 gene expression between meningothelial and non‐meningothelial meningiomas was statistically significant (P = 0.013). Our data supports the finding that alterations in NF2 gene alteration are histotype related but not grade related.

Multiple spinal ganglioneuromas in a patient harboring a pathogenic NF1 mutation.

Bacci C, Sestini R, Ammannati F, Bianchini E, Palladino T, Carella M, Melchionda S, Zelante L, Papi L. Multiple spinal ganglioneuromas in a patient harboring a pathogenic NF1 mutation.