Predictive value of progression-associated chromosomal aberrations for the prognosis of meningiomas: a retrospective study of 198 cases

[Cytogenetic alterations in meningioma tumors and their impact on disease outcome]

In recent years important advances have been achieved in the understanding of the genetic abnormalities present in meningioma tumors and its association with the ontogeny and progression of these tumor. Accordingly, while the presence of monosomy 22/22q-, associated with mutation of the NF2, BAM22, RRP22, GAR22, MN1, SMARCB1, CLH22 and/or LARGE genes, is associated with neoplasic transformation, other alterations such us monosomy 14, del(1p), different chromosomal abnormalities localized at 9p, 10q and 17q and complex karyotypes are frequently related to tumor progression. From the clinical point of view, currently available information about the impact of the different cytogenetic abnormalities on disease behavior and patient outcome is still scanty; nevertheless, the presence of gains of chromosome 22 in the context of a hyperdiploid karyotype, as well as del(1p) and monosomy 14 have been associated with a statistically significantly shorter recurrence-free survival, this later abnormality showing an independent prognostic value.

Hyperdiploidy defines a distinct cytogenetic entity of meningiomas

BACKGROUND

The most common chromosomal aberration found in meningiomas is monosomy 22. Progression and recurrence of meningiomas are usually associated with additional chromosome losses. Rarely, however, meningiomas have strongly hyperdiploid karyotypes with over 50 chromosomes; the objective of this study was to explore the cytogenetic and histopathologic patterns as well as the clinical significance of hyperdiploidy in meningiomas.

METHODS

Within a series of 677 consecutive meningiomas, we identified a subgroup comprising 16 cases that display a strikingly uniform pattern of hyperdiploidy mostly without structural chromosome rearrangements, as shown by banding techniques and, in the single structurally aberrant case, spectral karyotyping.

RESULTS

These meningiomas each have between 50 and 56 chromosomes, with trisomy 12 (14/16 cases), trisomy 20 (13/16 cases), trisomy 5 (12/16 cases), and trisomy 17 (10/16 cases). Histomorphologically, hyperdiploid meningiomas feature a heterogeneous phenotype. However, they are associated with a higher histological grade, and decreased expression of alkaline phosphatase as compared to meningiomas with typical karyotype. In two patients, recurrences were documented and three patients died of disease during the period of observation, indicating a worse prognosis of hyperdiploid than of cytogenetically typical meningiomas.

CONCLUSION

We conclude that hyperdiploidy constitutes a small but clinically relevant entity of biologically aggressive meningiomas, which are cytogenetically distinguishable from the majority of common-type meningiomas.

Histopathologic indicators of recurrence in meningiomas: correlation with clinical and genetic parameters

Meningiomas in general are circumscribed slow-growing tumors. However, despite gross total resection, tumor relapse and patients' outcome are still an issue. Risk stratification based on histomorphology alone remains problematic. This study explored the independent prognostic value of potential risk factors among 206 patients who underwent meningioma resection and followed-up until death or a median of 44 months. The statistical analysis considered clinical data, histomorphologic parameters, cytogenetic findings, Ki-67 immunoreactivity, and activity of tissue non-specific alkaline phosphatase (ALPL). Recurrence-free survival estimates were computed and prognostic factors were identified using Cox proportional hazards model. Independent predictors of recurrence included (1) anaplasia; (2) mitotic index > or =20/10 high-power fields; (3) subtotal tumor resection; (4) loss of short arm of chromosome 1 (1p-); and (5) Ki-67 labeling index (LI) >12%. Among totally resected WHO grade I meningiomas, neither histopathologic nor clinical parameters were predictive, whereas 1p- was the only independent prognostic factor. ALPL did not reach significance in the multivariate modeling, however, the fast and low-cost histochemical detection of ALPL expression could be proved as a highly sensitive screening method for 1p-. In particular, biologically aggressive meningiomas of histologically benign or "borderline" phenotype could be therefore identified by ALPL detection followed by 1p in situ hybridization.

Recurrent cytogenetic aberrations in histologically benign, invasive meningiomas of the sphenoid region

Meningiomas that arise in the sphenoid region (MSR) often display growth patterns leading to widespread invasion and destruction of the surrounding structures. Consequently, there is still estimated recurrence rate up to 30% with MSR. Conventional cytogenetic studies have failed to reveal aberrations characteristic of invasive meningiomas. Here we investigated 10 invasive and 5 non-invasive MSR using the array-based comparative genomic hybridization (array-CGH) with the GenoSensor Array 300. Mean number of aberrations detected per tumor was significantly greater for invasive meningiomas-67.4 compared with 40.5 for non-invasive MSR. Additionally, invasive MSR disclosed frequent losses on 1p, 6q, 14q and gains on 15q and 20, which were identified previously as molecular hallmarks of stepwise meningioma progression. Thus, the presence of a complex cytogenetic profile and progression-associated chromosomal aberrations in benign MSR is associated with their increased invasive potential. Inasmuch as no reliable adjuvant therapy for recurrent meningiomas is available thus far, revealed genomic aberrations can provide a potential targets for drug discovery and therapeutic intervention in a future.

The cytogenetic relationship between primary and recurrent meningiomas points to the need for new treatment strategies in cases at high risk of relapse

PURPOSE

Recurrence is the major factor influencing the clinical outcome of meningioma patients although the exact relationship between primary and recurrent tumors still needs to be clarified. The aim of the present study is to analyze the cytogenetic relationship between primary and subsequent recurrent meningiomas developed within the same individual.

EXPERIMENTAL DESIGN

Multicolor interphase fluorescence in situ hybridization was done for the identification of numerical abnormalities of 12 chromosomes in single-cell suspensions from 59 tumor samples corresponding to 25 recurrent meningioma patients. In 47 of these tumors, the distribution of different tumor cell clones was also analyzed in paraffin-embedded tissue sections. In parallel, 132 nonrecurrent cases were also studied.

RESULTS

Most recurrent meningiomas showed complex cytogenetic aberrations associated with two or more tumor cell clones in the first tumor analyzed. Interestingly, in most individuals (74%), exactly the same tumor cell clones identified in the initial lesion were also detected in the subsequent recurrent tumor samples. In the recurrent tumor samples of the remaining cases (26%), we observed tumor cell clones related to those detected in the initial lesion but which had acquired one or more additional chromosome aberrations associated with either the emergence of new clones with more complex karyotypes or the disappearance of the most representative clones from the primary lesions. Multivariate analysis of prognostic factors showed that the Maillo et al. prognostic score, based on age of patient, tumor grade, and monosomy 14, together with tumor size was the best combination of independent variables for predicting tumor recurrence at diagnosis.

CONCLUSION

Overall, our results indicate that the development of recurrent meningiomas after complete tumor resection is usually due to regrowth of the primary tumor and rarely to the emergence of an unrelated meningioma, underlining the need for alternative treatment strategies in cases at high risk of relapse, particularly those with a high Maillo et al. prognostic score and larger tumors.

Microarray-Based Analysis of Spinal versus Intracranial Meningiomas: Different Clinical, Biological, and Genetic Characteristics Associated with Distinct Patterns of Gene Expression

It has long been recognized that spinal meningiomas show particular clinical and histological features. Here, we compare the clinico-biological characteristics as well as the genetic abnormalities and patterns of gene expression of spinal and intracranial meningiomas. Fourteen spinal and 141 intracranial meningioma patients were analyzed at diagnosis. In all tumors, interphase fluorescence in situ hybridization (iFISH) studies were performed for the detection of quantitative abnormalities for 11 different chromosomes. Additionally, microarray analyses were performed on a subgroup of 18 histologically benign meningiomas (7 spinal and 11 intracranial). Upon comparison with intracranial tumors, spinal meningiomas showed a marked predominance of psammomatous and transitional tumors (p = 0.001), together with a higher proportion of cases displaying a single tumor cell clone by iFISH (p = 0.004). In 86% of the spinal versus 56% of the intracranial tumors (p = 0.01), the ancestral tumor cell clone detected showed either absence of any chromosomal abnormality or monosomy 22/22q- alone. Analysis of gene expression profiles showed differential expression between spinal and intracranial meningiomas for a total of 1555 genes, 35 of which allowed a clear distinction between both tumor types. Most of these 35 genes (n = 30) showed significantly higher expression among spinal tumors and corresponded to genes involved in signal transduction pathways, which did not show a significantly different expression according to tumor histopathology. In summary, we show the occurrence of unique patterns of genetic abnormalities and gene expression profiles in spinal as compared to intracranial meningiomas that provide new insights into the molecular pathways involved in the tumorigenesis and progression of spinal meningiomas, and could help explain their particular clinical and histological features.

Holistic and network analysis of meningioma pathogenesis and malignancy

Meningiomas, which originate from arachnoid cells and constitute the largest subgroup of all intracranial tumors, are generally benign, yet have the capacity to progress into a higher histological grade of malignancy associated with an increase in biological aggressivity and/or capacity to recur. To elucidate meningioma pathogenesis and malignancy, we applied a holistic and network approach analyzing cDNA and tissue microarray results. A potential pathway leading to meningioma angiogenesis, apoptosis and proliferation was evidenced as well as a regulatory network of the biomarkers including Ki-67, AR, CD34, P53, c-MYC, etc. which might support clinical research. In this potential pathway, ITGB1 could be the most important "superoncogene" playing a vital role in apoptosis and proliferation, while FOXO3A, MDM4 and MT3 are important to the malignancy process. Some genes are first reported that could explain why radiation induces meningioma and why more female than male patients are affected. Further, we present the hypothesis that HIV-Tat protein might have a close relationship with meningioma pathogenesis and malignancy.

Molecular genetics of meningiomas

In this article the authors provide a brief description of the current understanding of meningioma genetics. Chromosome 22 abnormalities, especially in the Neurofibromatosis Type 2 (NF2) gene, have been associated with meningioma development. Loss of heterozygosity of chromosome 22 occurs in approximately 60% of meningiomas; however, loss of NF2 gene function occurs in only one third of these lesions. This discrepancy supports the theory that a second tumor suppressor gene exists on chromosome 22, and the authors introduce several possible gene candidates, including BAM22, LARGE, INI1, and MN1 genes. Deletions of 1p have also been shown to correlate with meningioma progression. The genetic similarities and differences among sporadic, NF2-associated, pediatric, and radiation-induced meningiomas are discussed, with the observation that the nonsporadic meningiomas have a higher incidence of multiple chromosomal abnormalities at presentation. Ultimately, a better understanding of the molecular pathways of meningioma tumorigenesis will lead to new, successful treatments.

Intratumoral patterns of clonal evolution in meningiomas as defined by multicolor interphase fluorescence in situ hybridization (FISH): is there a relationship between histopathologically benign and atypical/anaplastic lesions?

Meningiomas are cytogenetically heterogeneous tumors in which chromosome gains and losses frequently occur. Based on the intertumoral cytogenetic heterogeneity of meningiomas, hypothetical models of clonal evolution have been proposed in these tumors which have never been confirmed at the intratumoral cell level. The aim of this study was to establish the intratumoral patterns of clonal evolution associated with chromosomal instability in individual patients as a way to establish tumor progression pathways in meningiomas and their relationship with tumor histopathology and behavior. A total of 125 meningioma patients were analyzed at diagnosis. In all cases, multicolor interphase fluorescence in situ hybridization (iFISH) studies were performed on fresh tumor samples for the detection of quantitative abnormalities for 11 different chromosomes. In addition, overall tumor cell DNA content was measured in parallel by flow cytometry. iFISH studies were also performed in parallel on tissue sections in a subset of 30 patients. FISH studies showed that 56 (45%) of the 125 cases analyzed had a single tumor cell clone, all these cases corresponding to histologically benign grade I tumors. In the remaining cases (55%) more than one tumor cell clone was identified: two in 45 cases (36%), three in 19 (15%), and four or more clones in five cases (4%). Overall, flow cytometric analysis of cell DNA contents showed the presence of DNA aneuploidy in 44 of these cases (35%), 30% corresponding to DNA hyperdiploid and 5% to hypodiploid cases; from the DNA aneuploid cases, 35 (28%) showed two clones and 9 (7%) had three or more clones. A high degree of correlation (r >/= 0.89; P < 0.001) was found between FISH and flow cytometry as regards the overall quantitative DNA changes detected with both techniques, the former being more sensitive. Among the cases with chromosome abnormalities, the earliest tumor cell clone observed was frequently characterized by the loss of one or more chromosomes (64% of all meningiomas); loss of either a single chromosome 22 or, less frequently, of a sex chromosome (X or Y) and del (1p) was commonly found as the single initial cytogenetic aberration (30%, 5%, and 5% of the cases, respectively). Interestingly, an isolated loss of chromosome 22 was only found as the initial abnormality in one out of 14 atypical/anaplastic meningiomas, while the same cytogenetic pattern was present in the ancestral tumor cell clone of 32% of the benign tumors. Cytogenetic patterns based on chromosome gains were found in the ancestral tumor cell clone in 4% of the patients, 2% corresponding to tetraploid tumors. Overall, cytogenetic evolution of the earliest tumor cell clones was frequently associated with tetraploidization (31%). Our results show that meningiomas are genetically heterogeneous tumors that display different patterns of numerical chromosome changes, with the presence of more than one tumor cell clone detected in almost half of the cases including all atypical/anaplastic cases. Interestingly, the pathways of intratumoral clonal evolution observed in the benign tumors were different from those observed in atypical/anaplastic meningiomas, suggesting that the latter tumors might not always represent a more advanced stage of histologically benign meningiomas.

Meningiomas: Updating Basic Science, Management, and Outcome

BACKGROUND

Meningiomas are biologically complex and clinically and surgically challenging. These features, combined with the rewarding potential for cure, make them of great interest to neurologists, neurosurgeons, and neuroscientists alike.

REVIEW SUMMARY

Initially, we review the clinical context of meningiomas, particularly recent changes in histopathological classification, diagnosis, and neuroimaging. Secondly, the underlying basic science as it has evolved over the last decades is summarized. The status of areas recently of intense interest, such as steroid hormone receptors and oncogenic viruses is described. Additionally, emerging areas of great promise, such as cytogenetics and molecular biology are presented. Lastly, we describe recent advances in management. In particular, skull-base surgery, image-guided surgery, and advances in radiotherapy are emphasized. The possible impact of basic research on management and outcome is also outlined.

CONCLUSIONS

Although usually benign and amenable to cure, meningiomas still present significant diagnostic and treatment challenges. Advances in basic science, surgery, and adjuvant therapy are widening the potential for safe, effective, evidence-based management leading to even better outcomes

Prognostic value of allelic losses and telomerase activity in meningiomas

OBJECT

The goal of this study was to examine allelic losses and telomerase activity in meningiomas to determine whether they could be used to predict disease recurrence.

METHODS

To identify predictive markers of recurrence, a cohort of high-grade (24 World Health Organization [WHO] Grade II and six WHO Grade III) and low-grade (21 WHO Grade I) meningiomas was investigated for losses of heterozygosity (LOHs) on chromosomes 1p, 9p, 10q, 14q, and 22q, a deletion of CDKN2A, and telomerase activity. Results of molecular analyses were compared with radiological and histological findings and progression-free survival (PFS). Losses of heterozygosity on chromosomes 22q, 1p, and 10q, as well as telomerase activity were related to the WHO histological grades of the lesions (p < 0.01, p < 10(-5), p < 10(-4), and p = 0.002, respectively). In the absence of an LOH on 22q, the other alterations were found infrequently. Overall, the number of molecular alterations was closely related to the histological grades of the lesions (p < 10(-6)). An LOH on 22q occurred much more frequently in convexity or falx (33 [87%] of 38 lesions) than in skull base or spinal meningiomas (four [31%] of 13 lesions) (p < 0.001). The histological grade; Simpson grade; an LOH on chromosome 1p, 9p, or 10q; and telomerase activity were correlated with a shorter PFS time (p < 10(-4), p = 0.02, p = 0.000365, p = 0.022, p = 0.00027, and p = 0.000512, respectively).

CONCLUSIONS

On the basis of these data the authors suggest that LOH analysis and a telomerase activity assay could be useful to determine molecular predictors of outcome in patients with meningiomas.

Association of loss of 1p and alterations of chromosome 14 in meningioma progression

Meningiomas are usually benign tumors; however, they can recur after surgical resection and occasionally show histologic progression to a higher grade II and III malignancy. The second most frequently reported genetic abnormality after 22q loss is deletion of 1p, although alterations in 9q, 10q, and 14q are also implicated in meningioma progression. Fourteen tumors comprising six benign, four atypical, and four malignant meningiomas were examined by means of cytogenetic and fluorescence in situ hybridization analysis. All tumors showed losses in different regions of 1p, with 1p11, 1p13, 1p21, 1p22, 1p32, and 1q21 breakpoints; eight tumors also presented alterations of chromosome 14. Five of the six cases with deletions on 1p and normal chromosome 14 were grade I, and two were recurrent. All but one of the eight cases with simultaneous 1p deletion and alterations of chromosome 14 were grade II (3 cases) and grade III (4 cases); all the grade III cases were recurrent. These results support the possible association between changes in 1p and chromosome 14 with the evolution of aggressive meningiomas through tumor progression.

New classification scheme for the prognostic stratification of meningioma on the basis of chromosome 14 abnormalities, patient age, and tumor histopathology

PURPOSE

Meningiomas are usually considered benign tumors. However, relapses occur in 10% to 20% of all patients, including both histopathologically aggressive and benign tumors. This study explored the value of numerical abnormalities for 10 different chromosomes in meningiomas for predicting relapse-free survival (RFS).

PATIENTS AND METHODS

This study prospectively analyzed the frequency of numerical abnormalities of chromosomes 1, 9, 10, 11, 14, 15, 17, 22, X, and Y in 70 meningioma patients by fluorescence in situ hybridization and their relationship with disease characteristics at diagnosis and patients' outcome.

RESULTS

Results showed the presence of numerical abnormalities for one or more chromosomes in most patients (77%). Chromosome 22 in the whole series and chromosome Y in males were those more frequently altered, followed by chromosomes 1, 14, and X in females. Patients with abnormalities of chromosomes 1, 9, 10, 11, 14, 15, 17, the sex chromosomes, and gains of chromosome 22 were associated with adverse prognostic features, more frequent relapses, and shorter RFS. Multivariate analysis showed that tumor grade together with chromosome 14 status and age were the best combination of independent variables for predicting RFS. According to these variables, all patients with a score of two or more than two adverse prognostic factors had experienced relapse at 5 years, whereas none of those with a score of zero had experienced relapse 10 years after surgery.

CONCLUSION

In addition to age and histologic grade, abnormalities of chromosome 14 contribute to a better prognostic stratification of meningioma patients at diagnosis. Additional prospective studies in larger series of patients, also including larger numbers of patients who experienced relapse, are necessary to confirm the utility of the proposed predictive model.

Monosomy 7p in meningiomas: a rare constituent of tumor progression

We present karyotypes of 15 meningiomas with structural aberrations of chromosome 7, which were taken from a consecutive series of 400 cytogenetically characterized meningiomas. Twelve of these tumors (80%) displayed partial or complete monosomy 7p with a consensus deleted region of 7p12 approximately pter, in 6 of 15 cases arising from an unbalanced whole-arm t(1;7)(q11;p11), and in 4 of 15 cases from a whole-arm translocation involving other chromosomes. Other types of partial aneusomy 7 (3/15 cases) or balanced aberrations of chromosome 7 (2/15 cases) were relatively rare. In most cases (11/15), the centromeric region of chromosome 7 was involved in the rearrangements. We conclude that in meningiomas, the near-centromeric region of chromosome 7 is particularly prone to structural rearrangements most frequently resulting in monosomy 7p. The investigation of the histopathologic features of this rare cytogenetic subgroup of meningiomas showed no clear genotype/phenotype correlation. As 7 of 11 of the meningiomas with monosomy 7p belonged to World Health Organization grades II or III, which usually comprise less than 20% of all meningiomas, partial loss of 7p appears to be involved in tumor progression in meningiomas. Because monosomy 7p is typically associated with the strongly progression-associated monosomy 1p, however, monosomy 7p represents a cofactor more than a stand-alone feature of meningioma progression.

Spinal meningiomas: surgical management and outcome

Advances in imaging and surgical technique have improved the treatment of spinal meningiomas; these include magnetic resonance imaging, intraoperative ultrasonography, neuromonitoring, the operative microscope, and ultrasonic cavitation aspirators. This study is a retrospective review of all patients treated at a single institution and with a pathologically confirmed diagnosis of spinal meningioma. Additionally the authors analyze data obtained in 556 patients reported in six large series in the literature, evaluating surgical techniques, results, and functional outcomes. Overall, surgical treatment of spinal meningiomas is associated with favorable outcomes. Spinal meningiomas can be completely resected, are associated with postoperative functional improvement, and the rate of recurrence is low.

Meningioma: Un modelo de evolución citogenética en la iniciación y progresión tumoral

Meningiomas are tumors of the central nervous system with a great morphological heterogeneity. They are generally benign, and have the capacity to progress to a higher histological grade (atypical and anaplastic), which is associated with an increase in biological aggressivity and/or capacity to recur. Citogenetically this evolution is characterized by total or partial monosomy 22 in the early phase, continued by numerical and structural changes during tumor progression. In this study, we present a review of 85 cases of meningiomas: 43 benign, 28 atypical and 14 anaplastic. We study the clinical and histopathological features, and their correlation with cytogenetie abnormalities present in these tumors. Numerical aberrations such as monosomy of chromosome 10, 14 and 18, and structural abnormalities such as deletions on 1p are directly associated with a higher agressivity of tumors. An association of aberatons on 1p and chromosome 14 are more commonly found in atypical and anaplastic meningiomas. These facts imply that the presence of complex karyotypes progressively increases from grade I to grade III meningiomas. Furthermore, these karyotypes are common in recurrent tumors.

Management of malignant tumors of the anterior skull base: experience with 76 patients

As the management of anterior cranial fossa malignancies has undergone significant evolution, decreases in morbidity and mortality rates have occurred. In this article, the authors discuss the clinical presentation, neuroimaging findings, and management options for common anterior skull base malignancies. Also discussed are surgery-related indications and principles.