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PubMed2000

The importance of surgery in supratentorial ependymomas. Long-term survival in a series of 23 cases.

In view of the widely recognized correlation between extent of surgical resection and length of survival of children with intracranial ependymoma and the statement that total resection is more likely to be achieved in supratentorial than infratentorial primaries, we decided to review our experience with supratentorial ependymomas and the pertinent literature to verify the importance of surgery in treating this subgroup of pediatric ependymal neoplasms. Of 23 patients operated on, 12 are still alive without evidence of disease 72-357 months after surgery (mean 227, median 237 months). One girl treated by surgery alone was lost to follow-up after 234 months when she, and 7 other patients in the series, had already passed the end of the period of risk for recurrence according to Collins' law. Six surviving patients (2 with subependymoma and 4 with ependymoma) were treated by surgery alone and only 1, the oldest in the series, had to undergo a second operation for recurrence after 10 years. The idea of treating intracranial ependymoma by surgery alone was favored by eminent neurosurgeons in the past and has recently received renewed attention. This was in part the consequence of recognizing that unlike diffuse astrocytoma, in which neoplastic cells can be found up to several centimeters away from the apparent tumor borders, ependymoma has more or less well-defined margins and grows mainly by expansion. Early experience with the policy of electively deferring adjuvant therapy after radiologically controlled total resection of ependymoma seems encouraging, although postoperative MRI does not yet indicate absolute certainty. Close surveillance is recommended. The majority of ependymomas so far treated by surgery alone, with relatively good success, have been supratentorial. In conclusion, on the basis of our experience and a review of the literature we favor a change in attitude to the management of intracranial ependymomas, especially of the cerebrum, with radiologically controlled radical surgery alone followed by close surveillance with periodic MR imaging until the child passes the period of risk for recurrence according to Collins' law as the initial option. In children less than 3 years old the period of surveillance should be doubled. In case of recurrence, reoperation should be considered first, particularly for supratentorial primaries. Radiotherapy continues to be a major option in malignant ependymoma and unresectable primary or recurrent benign ependymoma.

Adolescent↗

PubMed2003

Sensitivity and specificity of epithelial membrane antigen staining patterns in ependymomas.

Pattern and extent of epithelial membrane antigen (EMA) immunoreactivity in ependymomas as compared to other glial tumors have only been investigated in small series. To determine sensitivity and specificity of EMA staining, 54 ependymomas were evaluated in comparison to 54 glioblastomas, 43 fibrillary astrocytomas and 21 oligodendrogliomas. Distinct punctate intracytoplasmic EMA immunoreactivity was observed in 48/54 ependymomas (89%), whereas ring-like EMA staining was observed in 17/54 ependymomas (31%). Apart from the absence in most myxopapillary ependymomas, neither staining pattern was related to tumor grade or localization. Dot-like EMA immunoreactivity was less frequently observed in glioblastomas [32/54 (59%), P<0.05 vs ependymomas], fibrillary astrocytomas [10/43 (23%), P<0.001 vs ependymomas] and oligodendrogliomas [2/21 (10%), P<0.001 vs ependymomas], whereas ring-like EMA staining was absent. Sensitivity and specificity of punctate EMA staining for the diagnosis of ependymoma as compared to other glial tumors were determined: A finding of 5 EMA dots/high-power field was associated with a sensitivity of 72% and a specificity of 81%. The presence of ring-like EMA positive structures was less sensitive (32%), but highly specific (100%). To conclude, distinct punctate and ring-like EMA staining might serve as sensitive and specific markers of ependymal differentiation in glial tumors and, thus, may aid the diagnosis of ependymoma.

Adolescent↗

PubMed1983

Intracranial ependymomas in childhood. Survival and functional results of 47 cases.

A pediatric series of 47 intracranial ependymomas (15 supra- and 32 infratentorial) is presented. All children were operated upon between 1969 and 1979. Among these children, 35 completed the treatment with radiotherapy. The irradiation was usually limited to the intracranial content but in 7 patients, it was extended to the spinal axis as well. Malignant ependymomas represented 69% of the whole series (86% of the supratentorial and 53% of the infratentorial ependymomas). The operative mortality rate was 17%. The 5-year survival rate was 39% in the whole series and 51% when excluding postoperative mortality. Recurrences developed in 41% of cases and metastases in 20%. The study of this series and of the literature points out that: (1) metastases from supratentorial ependymomas are not frequent, almost always supratentorial and secondary to a malignant ependymoma, and (2) metastases from infratentorial ependymomas are almost always intraspinal and occur in one third of these tumors. The rate of seeding is especially high in the case of malignant infratentorial ependymomas (50%) but is also 15% in the case of benign tumors. These data lead the authors to propose a craniospinal irradiation in the case of infratentorial ependymomas whether benign or malignant, an irradiation of only the brain in the case of malignant supratentorial ependymoma, an irradiation of only the tumoral bed when ependymomas are benign and supratentorial.

Brain Neoplasms↗

PubMed2001

Prognostic value of Ki-67 (MIB-1) and p53 in ependymomas.

To determine whether Ki-67 (MIB-1) and p53 have prognostic value in ependymomas, clinicopathologic study was undertaken in 29 patients with this tumor. The clinical course correlated well with the histological grade according to the World Health Organization (WHO) grading system, and it was the worst in patients with anaplastic ependymoma. The percent expression of MIB-1 and p53 correlated with the histological grade of malignancy. With regard to the subtypes of benign ependymoma, the clinical course was the worst in clear-cell ependymoma, which had a significantly higher expression of MIB-1 and p53 than the other subtypes. Tanycytic ependymoma showed the most benign clinical course and the lowest expression of MIB-1 and p53. Although the WHO grading generally tended to correlate with the clinical course of ependymomas, these two subtypes--clear-cell ependymoma and tanycytic ependymoma--exhibited biological properties different from those of other grade II ependymomas.

Adolescent↗

PubMed1999

Molecular genetic analysis of ependymal tumors. NF2 mutations and chromosome 22q loss occur preferentially in intramedullary spinal ependymomas.

Ependymal tumors are heterogeneous with regard to morphology, localization, age at first clinical manifestation, and prognosis. Several molecular alterations have been reported in these tumors, including allelic losses on chromosomes 10, 17, and 22 and mutations in the NF2 gene. However, in contrast to astrocytic gliomas, no consistent molecular alterations have been associated with distinct types of ependymal tumors. To evaluate whether morphological subsets of ependymomas are characterized by specific genetic lesions, we analyzed a series of 62 ependymal tumors, including myxopapillary ependymomas, subependymomas, ependymomas, and anaplastic ependymomas, for allelic losses on chromosome arms 10q and 22q and mutations in the PTEN and NF2 genes. Allelic losses on 10q and 22q were detected in 5 of 56 and 12 of 54 tumors, respectively. Six ependymomas carried somatic NF2 mutations, whereas no mutations were detected in the PTEN gene. All six of the NF2 mutations occurred in ependymomas of WHO grade II and were exclusively observed in tumors with a spinal localization (P = 0.0063). These findings suggest that a considerable fraction of spinal ependymomas are associated with molecular events involving chromosome 22 and that mutations in the NF2 gene may be of primary importance for their genesis. Furthermore, our data suggest that the more favorable clinical course of spinal ependymomas may relate to a distinct pattern of genetic alterations different from that of intracerebral ependymomas.

Adolescent↗

PubMed2000

Immunohistochemical markers for intracranial ependymoma recurrence. An analysis of 88 cases.

Intracranial ependymomas are the third most common primary brain tumor in children. Although clinical and histological criteria for ependymoma prognosis are recognized, studies have reported contradictory results. Prognostic significance based on immunohistochemistry of ependymomas has been reported in a few studies. Eighty-eight patients with intracranial ependymomas were examined retrospectively for immunoexpression of various tumor-associated antigens and apoptosis. The results demonstrated significant preponderance of expression of the tenascin, vascular endothelial growth factor protein (VEGF), epidermal growth factor (EGFR), and p53 protein in high-grade tumors. Also high-grade ependymomas revealed more prominent labeling indices (LI) for proliferative marker Ki-S1 and lower LI for cyclin-dependent kinase inhibitor p27/Kip1. For low-grade ependymomas the progression free survival time (PFS) was found to be significantly shorter for Ki-S1 LI>/=5%, and for tenascin, VEGF, and EGFR positivity. For high-grade ependymomas PFS was found to be significantly reduced for age <16 years, subtotal tumor removal, p27 LI <20%, p53 positivity, and for apoptotic index (AI) <1%. The classification regression tree analysis exhibited four groups of ependymomas; (1) low-grade tenascin negative (32 cases, recurrence rate=0), (2) high-grade with AI >/=1% (21 cases, recurrence rate=57%), (3) low-grade tenascin-positive (10 cases, recurrence rate=89%), and (4) high-grade with AI <1% (25 cases, recurrence rate=100%). So, the immunohistochemical variables were found to be strongest predictors of ependymoma recurrence and they seem to be useful for assessing individual tumor prognosis in routinely processed biopsy specimen.

Adolescent↗

PubMed2002

Comparative genomic hybridization detects specific cytogenetic abnormalities in pediatric ependymomas and choroid plexus papillomas.

Pathogenesis and genetic abnormalities of ependymomas are not well known and differential diagnosis with choroid plexus tumors may be difficult when these tumors are located in the ventricles. We analyzed 16 samples of primary pediatric ependymomas and seven choroid plexus tumors for significant gains or losses of genomic DNA, using comparative genomic hybridization (CGH). Four ependymoma samples were obtained after surgery for relapse, including one patient whose tumor was analyzed at diagnosis and at first and second relapses. Three out of 16 ependymomas and none of the choroid plexus tumors appeared normal by CGH. In the remaining ependymomas, the number of regions with genomic imbalance was limited. The most frequent copy number abnormality in ependymomas was 22q loss. In one patient from whom multiple samples could be analyzed during tumor progression, no abnormality was present at diagnosis; gain of chromosome 9 and loss of 6q were observed at first relapse and, at second relapse, additional genomic imbalances were loss of 3p, 10q, and chromosome 15. In choroid plexus tumors, recurrent abnormalities were gains of chromosome 7 and region 12q. The recurrent chromosomal abnormalities were clearly different between ependymomas and choroid plexus papillomas (CPP). Recurrent loss of 22q suggests that this region harbors tumor suppressor genes important in the pathogenesis of ependymomas; however, other pathogenic pathways may exist involving 6q and chromosome 10 losses or gain of 1q and chromosome 9. CPP can be distinguished from ependymoma on the basis of CGH abnormalities.

Brain Neoplasms↗

PubMedDate not supplied

Supratentorial ependymomas and subependymomas: CT and MR appearance.

OBJECTIVE: Our goal was to characterize the CT and MR features of supratentorial ependymomas and subependymomas. MATERIALS AND METHODS: The CT or MRI examinations of 11 supratentorial ependymomas (average patient age: 16 years) and 3 supratentorial subependymomas (average age: 60 years) were analyzed for tumor size, location, and appearance. RESULTS: Ependymomas were periventricular (nine), intraventricular (one), or both (one) and averaged 4 cm in diameter. Four of nine ependymomas examined by CT were calcified. Eight ependymomas had a cystic component. All seven ependymomas evaluated with MRI demonstrated prolonged T1 and T2 relaxation, with two having foci thought to represent intratumoral hemorrhage. The MR contrast enhancement patterns included an enhancing nodule within the wall of a cyst (four), heterogeneous enhancement of cystic/solid lesions (two), and homogeneous enhancement of a solid lesion (one). All subependymomas were solid intraventricular masses, averaging 2.6 cm in diameter. One had small amounts of calcification, and none were cystic. All three were isointense or hypointense to white matter on T1-weighted MR images and heterogeneous or hyperintense on T2-weighted images, with variable enhancement characteristics. Early (< 1 year) postsurgical recurrence was seen in two ependymomas and one subependymoma. CONCLUSION: Supratentorial ependymomas are typically large, cystic, calcified, extraventricular masses found in children and young adults. Supratentorial subependymomas are generally solid, intraventricular masses that are usually smaller than ependymomas and occur in an order patient population.

Adolescent↗

PubMed2003

Lumbosacral ependymomas: a review of the management of intradural and extradural tumors.

OBJECT: The goal of this study was to review the management of intra- and extradural ependymomas. Spinal ependymomas most commonly occur as intramedullary tumors throughout the spinal axis. In the lumbosacral region, ependymomas are most commonly associated with the conus medullaris and cauda equina, but can also occur extradurally in the sacrum, presacral tissues, or subcutaneous tissues over the sacrum. These two tumor locations produce different management concerns. Intradural ependymomas, especially those in the lumbosacral region, are now recognized for their potential to spread throughout the central nervous system (CNS), whereas extradural tumors elicit more concern for their association with extraneural metastases. METHODS: The authors have reviewed the literature regarding both of these distinct tumors and have summarized recommendations for the management of intra- and extradural lumbosacral ependymomas. For both tumors, it appears that gross-total resection is the treatment of choice when feasible. The role of radiation therapy has not been adequately studied for either tumor location, but most clinicians use this modality in patients with subtotal resection of intradural ependymomas, local recurrence, or CNS dissemination. Data supporting the use of radiation therapy for extradural ependymomas are lacking. There does not appear to be a significant role for chemotherapy in either tumor location. CONCLUSIONS: Despite the risk for local recurrence and CNS dissemination, the prognosis for intradural lumbosacral ependymomas is good, with a greater than 90% 10-year patient survival in most series. The prognosis for extradural ependymomas does not appear to be as good. Much depends on extradural tumor location, however; the outlook is better for dorsal sacral tumors than presacral tumors.

Adolescent↗

PubMed1976

Ependymomas and ependymoblastomas in children.

The authors analyze histologically verified cases of ependymoma and ependymoblastoma (malignant ependymoma) occurring in children in Connecticut from 1935 to 1973. Of the 488 central nervous system tumors diagnosed in that period, 44 (9%) of the 467 intracranial neoplasms and five (24%) of the 21 intraspinal tumors were of ependymal origin. An increase in the incidence of ependymomas was noted since the mid-1950's. The mean ages at diagnosis of ependymomas and ependymoblastomas were 5.6 and 5.0 years respectively. The male to female ratio was 0.6:1 for ependymomas and 1.7:1 for ependymoblastomas. Epencymomas were found above and below the tentorium with similar frequency; however, viturally all of the epencymoblastomas occurred supratentorially. Presenting symptoms and physical findings were reviewed. A significant difference (p less than 0.05) was noted in the seizure rates of supratentorial ependymomas (9%) and ependymoblastomas (38%). A significantly increased survival (p less than 0.05) was associated with supratentorial ependymal neoplasms relative to infratentorial from 42 months following diagnosis onward. Contrary tp the reports of no clinical difference between ependymomas and ependymoblastomas, children with supratentorial ependymomas were noted to have a significantly longer survival (p less than 0.05) than those with similarly situated ependymoblastomas, with the difference noted from 18 months following diagnosis onward. The children treated by operation and irradiation had a significantly greater survival (p less than 0.05) than those treated by other methods; furthermore, with this treatment, longer survivals were noted in the ependymoma patients as compared to those with epencymoblastomas. This difference became significant (p less than 0.05) at 27 months after diagnosis. Operative mortality decreased from 40% to 17% in the last decade of the study as compared to the previous decade. Steroid therapy may have contributed to this decreased operative mortality, but it had no statistically significant effect on length of survival. The clinical course of intracranial ependymal neoplasms in adults and children was compared and appeared to be essentially the same.

Adolescent↗

PubMed2003

[Therapeutic results of eight patients with intracranial ependymomas].

Between 1985 and 2001, eight patients with intracranial ependymomas underwent surgery at our hospital. The cases included six infratentorial ependymomas, one supratentorial ependymoma and one supratentorial anaplastic ependymoma. Infratentorial ependymomas were classified according to origin and extension. The lateral type tumors originated from the lateral part of the fourth ventricle in four cases. The midfloor type tumors originated from the inferior half of the fourth ventricular floor in two cases. The three totally resected tumors were the lateral type tumors. The remaining one case with the lateral type tumor underwent nearly total resection of the tumor, since the tumor involved lower cranial nerves. All patients with the midfloor type tumors underwent incomplete resections of the tumors, because the tumors infiltrated into brain stem. Lower cranial nerve involvement and brain stem invasion implied incomplete resection and had the poor prognosis. In intracranial ependymomas, all four patients with total resections have been alive, whereas three of four patients with incomplete resections have died. The mean survival time of all patients with intracranial ependymomas was 127 months from the time of the initial surgery. There were no deaths in the patients with tumors showing MIB-1 index < 10% (n = 4). The mean survival time of the patients with tumors showing MIB-1 index > or = 10% (n = 4), was 30 months. The extent of the resection, the age of the patients and MIB-1 index are important factors in the outcome in patients with intracranial ependymomas. Two representative children aged less than 3 years with the midfloor type tumors were presented. In a patient treated with conventional radiation and chemotherapy, residual tumor repeatedly enlarged within 12 months despite several resections of the tumor. The patient died 32 months after the initial resection. In contrast, the other patient received multidisciplinary treatment including Linac stereotactic radiotherapy (SRT) with a marginal dose of 27 Gy in 9 fractions, have been still alive for 45 months after the initial resection. The residual tumor slightly decreased in size and remained stable without evident growth 12 months after SRT. SRT may provide good local control for patients with intracranial ependymomas and have a favorable impact on survival.

Adolescent↗

PubMed2003

MRI features of intramedullary spinal cord ependymomas.

BACKGROUND AND PURPOSE: To assess the magnetic resonance (MR) imaging characteristics of spinal intramedullary ependymomas. METHODS: MR images were obtained from 60 patients with spinal intramedullary ependymomas. All patients were treated surgically, and pathological diagnoses were confirmed. MR images of ependymomas and associated cysts were correlated with surgical findings. RESULTS: Among 60 cases of intramedullary ependymomas, 39 were cervical and 11 thoracic, and 10 were located at the conus medullaris and filum terminale. The lesions measured 1 to 10 vertebral segments in length along the neuraxis, with a mean length of 3.7 segments. All tumors had slightly hyperintense signals on T2-weighted MR images. Clear tumor margins were seen in 77% of patients; 75% had uniform contrast enhancement. Rostral and caudal cysts were seen in 90% of all patients; all cysts were hypointense on T1-weighted images and hyperintense on T2-weighted images. The rostral cysts were 1 to 5 segments in length and caudal cysts 2 to 10 segments in length. CONCLUSION: Ependymomas occur most often at the upper cord rather than in the conus medullaris and filum terminale. Of the cervical and thoracic ependymomas, most were cellular or epithelial types. Papillary ependymomas occurred exclusively in the conus medullaris and filum terminale. Rostral and caudal cysts are frequently associated with intramedullary ependymomas. Clear tumor margins, more uniform enhancement, and central locations can help differentiate ependymomas from other intramedullary spinal cord tumors.

Adult↗

PubMed2001

Molecular genetic alterations on chromosomes 11 and 22 in ependymomas.

Ependymomas arise from the ependymal cells at different locations throughout the brain and spinal cord. These tumors have a broad age distribution with a range from less than 1 year to more than 80 years. In some intramedullary spinal ependymomas, mutations in the neurofibromatosis 2 (NF2) gene and loss of heterozygosity (LOH) on chromosome arm 22q have been described. Cytogenetic studies have also identified alterations involving chromosome arm 11q, including rearrangements at 11q13, in ependymomas. We analyzed 21 intramedullary spinal, 14 ventricular, 11 filum terminale and 6 intracerebral ependymomas for mutations in the MEN1 gene, which is located at 11q13, and mutations in the NF2 gene, which is located at 22q12, as well as for LOH on 11q and 22q. NF2 mutations were found in 6 tumors, all of which were intramedullary spinal and all of which displayed LOH 22q. Allelic loss on 22q was found in 20 cases and was significantly more frequent in intramedullary spinal ependymomas than in tumors in other locations. LOH 11q was found in 7 patients and exhibited a highly significant inverse association with LOH 22q (p<0.001). A hemizygous MEN1 mutation was identified in 3 tumors, all of which were recurrences from the same patient. Interestingly, the initial tumor corresponded to WHO grade II and displayed LOH 11q but not yet a MEN1 mutation. In 2 subsequent recurrences, the tumor had progressed to anaplastic ependymoma (WHO grade III) and exhibited a nonsense mutation in exon 10 of MEN1 (W471X) in conjunction with LOH 11q. This suggests that loss of wild-type MEN1 may be involved in the malignant progression of a subset of ependymomas. To conclude, our findings provide evidence for different genetic pathways involved in ependymoma formation and progression, which may allow to define genetically and clinically distinct tumor entities.

Adolescent↗

PubMed1993

The growth potential of ependymomas with varying grades of malignancy measured by the Ki-67 labelling index and mitotic index.

The prognostic significance of histopathological grade for postoperative outcome is not yet known for ependymomas. Data on proliferation kinetics of these tumors are few. In our study, the growth fraction was immunohistochemically determined by labelling cell nuclei with the monoclonal antibody Ki-67 in 24 tumors of the ependymoma group (2 malignant ependymomas grade III, 11 ependymomas grade II, 8 spinal ependymomas, and 3 subependymomas). The results were compared with the mitotic index in the same tumor areas. Both growth parameters are related to the grade of malignancy. The differences between the results of spinal ependymomas (grade I) and of intracranial tumors (grade II) were statistically significant. Malignant ependymomas had the highest values. Variable growth potentials could be demonstrated in a few tumors. A non-linear relationship between growth fraction and mitotic index was found, indicating a variable generation time in ependymomas (as in astrocytomas). Thus, with rising grade of malignancy the growth fraction increases and the generation time decreases.

Adolescent↗

PubMed1990

Localization and significance of peanut agglutinin-binding sites on ependymoma cells.

It has been suggested that peanut agglutinin (PNA)-binding sites in benign and malignant tissues were quite different. To clarify the difference of PNA-binding sites between benign and malignant ependymoma, PNA-binding sites are investigated on the surface membrane of tissues from benign and malignant ependymomas and cultured ependymoma cells. In four of five malignant ependymoma cases, PNA binding occurred in a diffuse cell membrane fashion or granular intracytoplasmic fashion without neuraminidase treatment. On the other hand, PNA binding was observed without neuraminidase treatment in only two of eight benign ependymoma cases. After neuraminidase treatment, all of our benign and malignant ependymoma cases evidenced PNA binding. PNA binding was clearly evident on the cell membrane of ependymoma cells which were able to express organotypic structures, that is, to form ependymal rosettes after neuraminidase treatment. Normal rat ependymal cells showed PNA binding only after neuraminidase treatment. These findings suggest that the masking of PNA-binding sites of ependymoma cells by sialic acid may be correlated with tumor cell differentiation.

Ependymoma↗

PubMed2005

Treatment of spinal cord ependymomas by surgery with or without postoperative radiotherapy.

PURPOSE: To evaluate the effectiveness of complete resection and postoperative radiotherapy in spinal cord ependymomas. METHODS AND MATERIALS: We conducted a retrospective study over 20 patients (13 males and 7 females) with histologically confirmed spinal cord ependymomas between July 1985 and April 2001. Among them, 13 patients had ependymomas, 6 had myxopapillary ependymomas, and 1 had anaplastic ependymoma. All patients received radical surgery for tumor removal with 13 patients achieving complete resection and 7 incomplete resection due to technical difficulty. Among those with incomplete resection, 6 patients received postoperative radiotherapy to tumor bed and only one patient with anaplastic ependymoma received surgery alone. The total tumor dose ranged from 50 to 60 Gy. RESULTS: Among the 20 patients, 19 patients were alive and showed local control. The median survival time of all patients was 109 months, with 104 months in the complete resection alone group and 135 months in the incomplete resection with postoperative radiotherapy group. One patient with anaplastic ependymoma and no postoperative radiotherapy developed leptomeningeal seeding 9 months after surgery. Salvage therapy of radiotherapy and chemotherapy maintained normal neurological functions. The patient expired 34 months from the initial diagnosis due to progression of leptomeningeal seeding. CONCLUSION: Complete resection alone in spinal cord ependymoma can achieve excellent local control and survival. Patients should receive complete resection if technically possible. Postoperative radiotherapy is not recommended for complete resection. For incomplete resection, postoperative local radiotherapy is recommended and it can also achieve excellent local control and survival. Local radiotherapy with 50-60 Gy is effective and safe. Salvage radiotherapy improves quality of life for local recurrence or leptomeningeal seeding patients.

Adult↗

PubMed2006

Chromosomal imbalances in clear cell ependymomas.

Clear cell ependymoma is a rare and diagnostically challenging subtype of ependymoma, whose genetic features are essentially unknown. We studied 13 clear cell ependymomas (five cases WHO grade II, eight cases WHO grade III) by comparative genomic hybridization (CGH). Chromosomal imbalances were found in 12/13 cases. The most common aberrations overall were +1q (38%), -9 (77%), -3 (31%), and -22q (23%). Clear cell ependymomas of WHO grade II were characterized by -9 (40%), whereas WHO grade III cases mainly showed +1q (63%), and +13q (25%), as well as -9 (100%), -3 (38%), and -22q (25%). In contrast to other ependymal tumors, clear cell ependymomas of WHO grade II showed fewer imbalances than WHO grade III samples (1.4 vs 3.5 per case). Although some of the implicated chromosomes have previously been shown to be involved in other ependymoma variants, the striking frequency of +1q, -9, and -3 suggests that aberrations differ between clear cell and other types of ependymomas, in particular, for loss of chromosome 9 which can be regarded as the molecular hallmark of clear cell ependymomas.

Adolescent↗

PubMed2002

Differential involvement of protein 4.1 family members DAL-1 and NF2 in intracranial and intraspinal ependymomas.

Ependymomas are malignant CNS neoplasms with highly variable biologic behavior, including a generally better prognosis for intraspinal tumors. Inactivation of the NF2 gene on 22q12 and loss of its protein product, merlin, have been well documented in subsets of meningiomas and ependymomas. DAL-1, a related tumor suppressor and protein 4.1 family member on 18p11.3, has also been recently implicated in meningioma pathogenesis, though its role in ependymoma remains unknown. Therefore, we evaluated 27 ependymomas (12 intracranial and 15 spinal) using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) to determine NF2/merlin and DAL-1/DAL-1 status at the DNA and protein levels. Demonstrable NF2 and DAL-1 gene deletions were each detected in 6 (22%) ependymomas. All 5 merlin losses by IHC occurred in spinal ependymomas (P =.047), whereas 5 (71%) DAL-1-negative cases were intracranial (P =.185). The former result is consistent with prior observations that NF2 mutations are generally limited to spinal ependymomas. In contrast to meningiomas, simultaneous merlin and DAL-1 losses were not encountered. Our findings suggest that (1) NF2 and DAL-1 losses are involved in the pathogenesis of spinal and intracranial ependymoma subsets, respectively and (2) given the number of cases with no demonstrable losses, other cellular perturbations must also be critical for tumori-genesis.

Adolescent↗