Skip to main content
NCBI home page
The American Journal of Pathology logoLink to The American Journal of Pathology
. 2001 Apr;158(4):1525–1532. doi: 10.1016/S0002-9440(10)64103-X

Pediatric High-Grade Astrocytomas Show Chromosomal Imbalances Distinct from Adult Cases

Christian H Rickert *¶, Ronald Sträter †, Peter Kaatsch ‡, Hansdetlef Wassmann §, Heribert Jürgens †, Barbara Dockhorn-Dworniczak , Werner Paulus *
PMCID: PMC1891902  PMID: 11290570

Abstract

We studied 23 pediatric high-grade astrocytomas by comparative genomic hybridization. Chromosomal imbalances were found in 10 of 10 anaplastic astrocytomas and 11 of 13 glioblastomas and consisted of +1q (43%), +3q (26%), +1p, +2q, +5q (22%), −22q (34%), −6q, −10q (30%), −9q, −11q, −13q, −16q, and −17p (22%). Anaplastic astrocytomas frequently showed +5q (40%), +1q (30%), −22q (50%), −6q, −9q (40%), and −12q (30%); glioblastomas +1q (54%), +3q (38%), +2q, +17q (23%), −6q, −8q, −10q, −13q, and −17p (31%). Minimal common regions mapped to +1q21-41, +3q27-qter, +2q31-32, +5q14-22, −22q12-qter, −10q23-25, −6q25-qter, −9q34.2, −11q14−22, −16q22-qter, and −17p. High-level gains were located on 1q (7 cases), 2q, 7q (4 cases), 3q (3 cases), 9, 17q (2 cases), 4q, 8q, 18, and 20q (1 case). A significantly shorter survival was found for anaplastic astrocytomas showing +1q (P < 0.05), MIB-1 proliferation index >25% (P < 0.001) and glioblastomas (P < 0.05). Compared with adult cases, +1p, +2q, and +21q as well as −6q, −11q, and −16q were more frequent in pediatric malignant astrocytomas. Among the latter +5q, −6q, −9q, −12q, and −22q were characteristic for pediatric anaplastic astrocytomas and +1q, +3q, +16p, −8q, and −17p for pediatric glioblastomas. Our results show that chromosomal aberrations differ between pediatric anaplastic astrocytomas and glioblastomas as well as between pediatric and adult high-grade astrocytomas, supporting the notion of a different genetic pathway. Furthermore, gains of chromosomal material on 1q might be correlated with a worse prognosis in pediatric anaplastic astrocytomas.

Astrocytomas are the most common pediatric brain tumors and account for 40.9% of cerebral and 7.7% of all childhood cancers. 1 High-grade astrocytomas, ie, anaplastic astrocytomas and glioblastomas, however, are rarer compared with their adult counterparts and make up 6.6% of pediatric brain tumors. 1 Relatively few studies have been performed on their molecular properties, and different genetic pathways seem to be involved in the evolution of pediatric and adult high-grade astrocytomas.

Comparative genomic hybridization (CGH) is able to identify imbalances of the entire genome in terms of DNA copy number changes. Its main advantage is that it bypasses the need for laborious cell culture to harvest metaphase spreads, and that it can be applied to archival material. Although it has previously been used in a few studies on adult high-grade astrocytomas, no CGH study has hitherto been undertaken on pediatric high-grade astrocytomas. To screen for DNA copy number changes that may be involved in tumorigenesis of pediatric malignant astrocytomas, we applied CGH on anaplastic astrocytomas and glioblastomas from 23 patients under 18 years of age.

Materials and Methods

Patients and Tumors

Formalin-fixed and paraffin-embedded biopsy specimens of 23 primary pediatric high-grade astrocytomas were investigated (Table 1) ▶ . These consisted of 10 anaplastic astrocytomas World Health Organization grade III (three males, seven females; mean age, 7.1 years; range, 8 months to 17 years) and 13 glioblastomas World Health Organization grade IV [six males, seven females (including two sisters; cases 12 and 13); mean age, 8.9 years; range, 1 to 16 years]. Of these, 20 tumors were located supratentorially (9 anaplastic astrocytomas, 11 glioblastomas), two in the cerebellum (one anaplastic astrocytoma, one glioblastoma), and one in the brain stem (one glioblastoma). The pediatric age group was defined as patients under 18 years of age at the time of operation. All patients underwent surgery or stereotactic biopsy. A combination of postoperative radiation therapy and chemotherapy was applied to eight patients, whereas 10 patients underwent radiation therapy and three patients underwent chemotherapy alone; two children did not receive any adjuvant therapy (Table 1) ▶ . Clinical follow-up data were available for all patients.

Table 1.

Clinical Data of 23 Biopsy Specimens from Pediatric Anaplastic Astrocytomas and Glioblastomas

Case no. Age, years Sex MIB Location Therapy Clinical course Survival, months
Anaplastic astrocytomas (WHO III)
1 0.7 M 13.9 Parietal CT Stable disease >27
2 8 F 3.0 Parietal RT/CT Free of disease >48
3 16 F 5.9 Temporal RT/CT Progress 20
4 6 F 20.9 Hypothalamus RT/CT Remission >30
5 17 F 7.8 Parietal RT Remission >38
6 5 F 37.6 Parietal − Progress 3
7 4 M 38.5 Parietal RT/CT Progress 4
8 0.7 F 12.2 Temporal RT/CT Remission >102
9 12 M 3.6 Cerebellum RT Remission >77
10 2 F 16.8 Temporal − Progress 3
Glioblastomas (WHO IV)
11 15 M 11.7 Fronto-parietal RT Free of disease >23
12 5 F 50.8 Temporal RT Progress 1
13 7 F 49.7 Parietal RT Progress 6
14 4 M 41.9 Paraventricular RT/CT Progress 11
15 11 M 24.2 Brain stem RT/CT Progress 31
16 4 F 36.8 Parietal RT Progress 15
17 6 F 39.9 Parieto-occipital RT/CT Progress 8
18 12 F 12.6 Frontal RT/CT Progress 12
19 15 M 33.4 Thalamus RT Progress 9
20 14 F 51.1 Occipital RT Progress 16
21 5 M 26.1 Parietal RT Progress 11
22* 16 M 22.2 Temporal RT Progress 8
23 1 F 12.8 Cerebellum CT Remission >8
Open in a new tab

M; male, F; female, MIB-1; proliferation index in percent; RT; radiotherapy; CT; chemotherapy.

*Giant cell glioblastoma.

Histological criteria for classifying a tumor as anaplastic astrocytoma or glioblastoma were those of the World Health Organization classification. 2 Only tumor samples that had been shown histologically to contain >70% of tumor cells were included. Routine hematoxylin and eosin staining and immunohistochemistry using an avidin-biotin complex technique and monoclonal antibodies against glial fibrillary acid protein as well as the proliferation antigen Ki-67 (clone MIB-1) were performed. Statistical analysis was performed using Kaplan-Meier estimates of survival probabilities and the log-rank test.

CGH Analysis

DNA was isolated by phenol-chloroform extraction according to standard protocols. With minor modifications, CGH analysis was performed as described previously. 3 Briefly, tumor DNA was labeled with biotin-16-dUTP (Boehringer Mannheim, Mannheim, Germany) and reference DNA from a healthy male donor with digoxigenin-11-dUTP (Boehringer Mannheim) in a standard nick translation reaction. The DNase concentration in the labeling reaction was adjusted to reveal an average fragment size of 200 to 500 bp. The labeled DNA fragments were purified from remaining nucleotides by column chromatography.

For CGH, 500 ng of tumor DNA, 300 ng of reference DNA, and 30 μg of human Cot1 DNA (Gibco, Karlsruhe, Germany) were co-precipitated and redissolved in 10 μl of hybridization buffer. Denaturation of DNA (75°C for 5 minutes) was followed by a pre-annealing time of 45 minutes at 37°C. Target metaphase spreads (46,XY), which had been prepared following standard procedures, were denatured separately in 70% formamide/2× standard saline citrate for 2 minutes at 72°C. Hybridization was allowed to proceed for 3 to 4 days. Posthybridization washes were performed to a stringency of 50% formamide/2× standard saline citrate at 45°C and 0.1× standard saline citrate at 60°C. Biotinylated and digoxygenated sequences were detected simultaneously, using avidin-fluorescein isothiocyanate (1:200; Boehringer Mannheim) and anti-digoxigenin-rhodamine (1:40; Boehringer Mannheim). The slides were counterstained with 4,6-diamidino-2-phenylindole (DAPI) and mounted in an antifade solution (Vectashield; Vector Laboratories, Burlingame, CA).

Microscopy and Digital Image Analysis

Separate digitized gray level images of DAPI, fluorescein isothiocyanate, and rhodamine fluorescence were taken with a charge-couple device camera connected to a Leica DMRBE microscope (Leica, Wetzler, Germany). The image processing was performed by use of Applied Imaging Software (Applied Imaging, Sunderland, UK). Average green-red ratios were calculated for each chromosome in at least 10 metaphases.

Chromosomal regions with CGH ratio profiles surpassing the 50% CGH thresholds (upper threshold, 1.25; lower threshold, 0.75) were defined as loci with copy number gains or losses. Based on experiments with normal control DNA, these thresholds have been shown to eliminate false-positive results. These values have been used in several studies comparing CGH data with results obtained by other cytogenetic methods and have proven to provide robust criteria for the diagnosis of chromosomal gains and losses. Overrepresentations were diagnosed as high-level gains or amplifications when the fluorescence intensity levels exceeded 1.5 or when the fluorescein isothiocyanate fluorescence showed strong focal signals. For the assignment of these high-level amplifications to chromosomal bands, the signal intensities were compared to the DAPI banding on individual chromosomes. As tumor specimens and normal DNA were not sex matched, X and Y chromosomes were excluded. Also excluded were centromeric and satellite regions of the acrocentric chromosomes and chromosome 19 because of the abundance of highly repetitive DNA sequences as well as the frequent occurrence of false-positive CGH results as shown by interphase fluorescence in situ hybridization using suitable DNA probes.

Results

CGH revealed DNA copy number changes in 10 of 10 anaplastic astrocytomas and 11 of 13 glioblastomas; six patients showed only one chromosomal imbalance each (Table 2) ▶ . Every chromosome was shown to carry imbalances (Figure 1) ▶ ; most imbalances were found on chromosomes 1 (14 cases), 6 (11 cases), and 17 (10 cases), the fewest on chromosomes 14 and 15 (2 each). The most DNA copy number changes were detected in an anaplastic astrocytoma (19 changes), the fewest in two glioblastomas (none). Anaplastic astrocytomas showed an average of 6.6 chromosomal changes per tumor (range, 1 to 19; 2.9 gains versus 3.7 losses), which were more common than in glioblastomas with an average of 6.1 changes per tumor (not significant; range, 0 to 18; 2.8 gains versus 3.3 losses) (Table 1 ▶ , Figure 1 ▶ ). Losses were more common than gains in both entities (not significant).

Table 2.

Gains and Losses in DNA Copy Number by CGH

Case Gains (respective top lines) and losses (respective bottom lines)
Anaplastic astrocytomas (WHO III)
1 -
9q34.2, 10q23-25
2 -
9
3 1, 2, 4q, 7, 8q, 15q, 16, 17q22-qter, 20q, 21
3q, 5q, 6q25-qter, 8p, 10q23-25, 12q21.2-qter, 13q, 18, 22q12-qter
4 2q31-32, 3q25-qter, 4, 5p, 5q11.2-23.2, 9, 20, 21q
1p, 6, 7q, 8, 10q, 11q, 12q, 16, 22q
5 -
9
6 -
6q24-qter, 11q14-22, 22
7 1, 5q11.2-23.2, 7, 9
3p22-24, 6q, 12, 17p, 21q
8 5q11.2-22, 6q12-16, 13q22
16, 17q24-qter, 22q12-qter
9 5q14-23, 6q12-22, 12q21
1, 3, 9q22-qter, 22q12-qter
10 1q
Glioblastomas (WHO IV)
11 1p34.2-pter, 16
-
12 -
-
13 1q21-41
-
14 8q
6q14, 6q22-qter, 9q, 13q12-21, 17p
15 1q, 2, 3q, 8q, 17q23-qter
14q, 16q, 20p
16 1p31.2-34.2, 1q, 2(2q23-32), 3q26.2-qter, 7, 17q, 18
4q28.2-qter, 6q16.2-qter, 8q, 10, 11q, 16, 17p
17 -
-
18 3q27-qter
4q28.2-qter, 5q13-15, 9p, 10q, 13q, 22q
19 1q, 3q27-qter, 12q24.3, 17q
7q22-31, 16q22-qter, 18p
20 1q
-
21 1 (1q42-qter), 2q (2q23-34), 3q26.1-qter, 7 (7q), 9q13-qter, 16, 20, 21q
6, 8q, 10q, 11, 12q23-qter, 13q31-qter, 15q, 17p, 18q12-qter, 22q12-qter
22 1q, 4, 5p, 5q11.2-21, 21
2q14.1-qter, 6q14-qter, 8q, 10q, 11, 13q, 14q, 17p, 22q
23 16p
-
Open in a new tab

Bold type indicates high level gains.

Figure 1.

Figure 1.

Open in a new tab

CGH ideogram summarizing gains and losses of DNA sequences in pediatric anaplastic astrocytomas (gray) and glioblastomas (black). Gains are shown as bars on the right side of the chromosome ideogram and losses on the left. High-level amplifications are marked as dotted lines. Each vertical represents the affected chromosomal region seen in a single tumor specimen.

The most common DNA copy number changes overall were gains on 1q (43%), 3q (26%), 1p, 2q, and 5q (22%) as well as losses on chromosomes 22q (34%), 6q, 10q (30%), 9q, 11q, 13q, 16q, and 17p (22%). In anaplastic astrocytomas, the most frequent imbalances were gains on 5q (40%) and 1q (30%) as well as losses on chromosomes 22q (50%), 6q, 9q (40%), and 12q (30%). In glioblastomas, the most common DNA copy number changes were gains on 1q (54%) and 3q (38%), 2q, and 17q (23%) as well as losses on chromosomes 6q, 8q, 10q, 13q, and 17p (31%) (Table 1 ▶ , Figure 1 ▶ ).

Minimal common regions found in at least five tumors consisted of gains of 1q21-41 (10 cases), 3q27-qter (6 cases), 2q31-32, and 5q14-22 (5 cases) as well as losses of 22q12-qter (8 cases), 10q23-25, 6q25-qter (7 cases), 9q34.2, 10q, 11q14-22, 16q22-qter, and 17p (5 cases). High-level gains affecting whole chromosomes, as indicative of trisomy, were found on chromosomes 7 (3 cases), 1, 2, and 9 (2 cases), as well as on 18 (1 case). High-level gains affecting parts of a chromosome or chromosome arms were found on chromosomes 1q (7 cases), 2q, 7q (4 cases), 3q (3 cases), 17q (2 cases) as well as 4q, 8q, and 20q (1 case) (Figure 1) ▶ . Between one and five high-level gains were found in four of the anaplastic astrocytomas (cases 3, 4, 7, and 10), and between one and six in five of the glioblastomas (cases 15, 16, 19, 20, and 21) (Table 1) ▶ .

The mean MIB-1 proliferation indices were highly significantly different between anaplastic astrocytomas and glioblastomas and were 17.0% (range, 3.0 to 38.5%; SD, 12.2%) for anaplastic astrocytomas and 31.8% (range, 11.7 to 51.1%; SD, 14.6%) for glioblastomas (P < 0.01). All children could be followed-up, and the median overall survival was 15.0 months (SD, 3.8 months). At the time of reporting, 6 of 10 children with anaplastic astrocytomas were still alive (no median overall survival calculable because >50% of patients were still alive at time of reporting; mean overall survival, 64.2 months; SD, 14.7 months) whereas only 2 of 13 children with glioblastomas were still alive (median overall survival, 11.0 months; SD, 1.7 months; mean overall survival, 13.5 months; SD, 2.7 months); the difference in survival was statistically significant (P < 0.05). The respective 1-, 2-, and 3-year survival rates were 55, 33, and 21% for all malignant astrocytomas; 70, 60, and 50% for anaplastic astrocytomas; and 46, 9, and 0% for glioblastomas. A highly significantly shorter survival was found for all high-grade astrocytomas showing a MIB-1 proliferation index of >25% (median overall survival, 8.0 months; SD, 2.4 months; mean survival, 8.4 months; SD, 1.6 months) compared with tumors with a MIB-1 proliferation index of <25% (no median overall survival was calculable because >50% of patients were still alive at time of reporting; mean survival, 63.0 months; SD, 13.4 months; P < 0.001). Although the number of aberrations overall as well as of gains and losses on their own bore no significance on survival, a significantly shorter survival was found among pediatric anaplastic astrocytomas showing gains of 1q (median overall survival, 9.0 months; SD, 2.4 months; mean survival, 12.3 months; SD, 2.7 months) compared with cases without this imbalance (no median overall survival calculable because >50% of patients were still alive at time of reporting; mean survival, 87.9 months; SD, 13.3 months; P < 0.05) (Figure 2a) ▶ although no such correlation could be found for pediatric glioblastomas in which cases with +1q as well as those without +1q showed a median overall survival of 11.0 months (P = 1.00; Figure 2b ▶ ). No correlation could be found between prognosis and age, gender, or year of diagnosis.

Figure 2.

Figure 2.

Open in a new tab

Kaplan-Meier survival estimates showing significantly lower survival probabilities for children with anaplastic astrocytomas showing gains of 1q compared with cases without this change (A; P < 0.05), whereas no prognostic significance of +1q could be found in pediatric glioblastomas (B).

Discussion

Although malignant astrocytomas are fairly uncommon brain tumors in children, they are of great clinical interest regarding their potential therapeutic approach and improvement of prognosis that has led to the establishment of several multicenter treatment studies. However, little is known about their molecular biology and genetics with somewhat conflicting results. In most cytogenetic investigations, the main point of contention, particularly in view of the sometimes surprisingly long survival of children suffering from these tumors and the fact that astrocytic tumors with similar degrees of histological anaplasia often show different biological behavior, focused on whether pediatric and adult high-grade astrocytomas follow similar 4-6 or different 7-13 genetic pathways, and whether they show consistent or varying chromosomal changes. To date, no CGH study on primary pediatric anaplastic astrocytomas and glioblastomas has been reported.

Pediatric High-Grade Astrocytomas

Although a normal karyotype was found in 14 out of 22 pediatric anaplastic astrocytomas, 14 anaplastic astrocytomas all showed DNA copy number changes in our series. These were mainly characterized by gains of 5q and losses of 22q and 9q, whereas glioblastomas predominantly showed gains of 1q and 3q as well as losses of 6q, 10q, 13q, and 17p (Figures 1 and 3) ▶ ▶ . Some of these imbalances have previously been reported in pediatric malignant astrocytomas, namely losses of chromosomes 13, 9 17p, 5,6,9,15 and 22q. 5,6,14 Furthermore, losses of heterozygosity at 17p13.1, 9p21, and 10q23-25 were found in 50, 83, and 78% of high-grade pediatric astrocytomas, respectively. 13 TP53 tumor suppressor gene mutations (mapping to 17p13.1) have been found in 38% of pediatric high-grade astrocytomas, 13 25% of glioblastomas, 12,16 and 11% of anaplastic astrocytomas 16 as well as 71% of brain stem glioblastomas, 17 underscoring the proposed preferential inactivation of the p53 tumor suppressor pathway in >95% of pediatric astrocytomas. 18 On the other hand, mutations of the PTEN gene (mapping to 10q23-25) are rare in pediatric cases in which they are only found in ∼8% of tumors; 11,13 in our series chromosomal material of 10q was lost in 31% of tumors. Furthermore, no MDM2 (12q13-21) 15 or epidermal growth factor receptor (EGFR, mapping to 7q21-32) gene amplifications were detected in several investigations, 12,13,17-19 which is corroborated by the few CGH changes found by us at the aforementioned sites.

Figure 3.

Figure 3.

Open in a new tab

Comparison of CGH data of pediatric (gray) and adult (black) anaplastic astrocytomas (top) as well as pediatric (gray) and adult (black) glioblastomas (bottom), charted against each affected chromosomal arm. Relative frequency of chromosomal imbalances in percent; gains charted above, losses below the respective midlines. CGH results of primary adult high-grade astrocytomas gained from 22 anaplastic astrocytomas 21-24 and 184 glioblastomas. 21-29

A review of cytogenetic data from ∼200 pediatric glioblastomas demonstrated gains of chromosome 7 to be the most common imbalance encountered in 45% of tumors, followed by losses of 10, 9p, and 22q in 35, 20, and 17% of cases, respectively; very similar cytogenetic changes were reported for 43 pediatric anaplastic astrocytomas. 14 However, these aberrations as well as losses of other implicated chromosome regions like 1q 17 and 10p 5,6 played little or no role among our cases, except for losses of 22q in anaplastic astrocytomas and 10q in glioblastomas (Figure 1) ▶ . In contrast, our cases showed frequent and prognostically relevant gains of 1q, the most commonly amplified chromosomal region overall and associated with a poorer outcome, and one that has previously been implicated in pediatric low-grade but not hitherto in high-grade astrocytomas, 20 and losses of 9q rather than 9p (Figure 1) ▶ .

CGH in Pediatric and Adult High-Grade Astrocytomas

CGH results on primary adult high-grade astrocytomas have been presented in nine studies consisting of 22 anaplastic astrocytomas 21-24 and 184 glioblastomas. 21-29 Loss of genetic material of 10q was the most common chromosomal change overall and similarly frequent in the pediatric primary anaplastic astrocytomas and glioblastomas of this series (30 and 31%, respectively) and adults (32 and 59%) alike (Figure 3) ▶ . Multiple tumor suppressor genes on the long arm of chromosome 10 have been implicated in the development of astrocytic gliomas: 30 among glioblastoma mutations, deletions, and loss of heterozygosity on 10q have been found more frequently in primary compared with secondary glioblastomas and have predominantly been associated with the PTEN gene. 31,32 Gains of chromosome 7, containing the EGFR gene that is amplified in >30% of adult malignant astrocytomas, 33 and losses of 9p, although, were much more frequently found in adult malignant astrocytomas (32 to 58%) compared with pediatric cases (8 to 20%), whereas losses of 10p exclusively occurred among adult anaplastic astrocytomas and glioblastomas (27 and 51%) but not in any of our pediatric cases. In contrast, there was a marked prevalence for pediatric anaplastic astrocytomas and glioblastomas to show gains of chromosomes 1p (20 and 23% versus 5 and 9%), 2q (20 and 23% versus 9 and 3%), and 21q (20 and 16% versus 0 and 3%) as well as losses of 6q (40 and 31% versus 9 and 18%), 11q (20 and 23% versus 5 and 6%), and 16q (20 and 23% versus 5 and 5%). However, a recent microsatellite study on astrocytic tumors found losses affecting chromosome 6q in 38% of anaplastic astrocytomas and 37% of glioblastomas. 34 Chromosomal imbalances that seemed to be more characteristic for a specific tumor entity rather than a particular age group were gains of 9p for anaplastic astrocytomas (20% of pediatric and 14% of adult anaplastic astrocytomas versus 0 and 5% for glioblastomas) and losses of 13q, containing the retinoblastoma tumor suppressor gene, for glioblastomas (31% of pediatric and 38% of adult glioblastomas versus 10 and 23% for anaplastic astrocytomas). Furthermore, characteristic aberrations distinguishing the two tumor grades within the pediatric age group consisted of gains of 5q and losses of 9q, 12q, and 22q for anaplastic astrocytomas as well as gains of 1q, 3q, and 16p and losses of 8q and 17p for glioblastomas. Loss of 22q is a frequent event in several tumor entities, eg, ependymomas, pheochromocytomas, rhabdoid tumors, and hepatocellular, colorectal, ovarian, breast, and oral squamous cell carcinomas, and was observed in 17, 31, and 38% of adult low-grade, anaplastic astrocytomas and glioblastomas, respectively, consistent with a role in astrocytoma tumorigenesis and progression. 35 However, among our pediatric cases loss of 22q was most frequently encountered in anaplastic astrocytomas rather than glioblastomas (Figure 1) ▶ . Moreover, amplifications of CDK4 (12q), CCND1 (11q13), and CCND3 (6p21) that have been found in adult malignant gliomas 36 do not seem to play a role among pediatric high-grade astrocytomas (Figure 1) ▶ . Of the minimal common regions found in our series most are novel and have not previously been put forward. They consisted of gains of 1q21-41 (containing the proto-oncogenes SK1, PBX1, TRK/TRKC, ABL, and ELK4), 2q31-32, 3q27-qter (LAZ3/MLF1), and 5q14-22 (GAP) as well as losses of 6q25-qter (containing the tumor suppressor genes MAS and IGF2R), 9q34.2 (TSC1), 10q23-25 (PTEN), 11q14-22, 16q22-qter (CMAR/CAR and E-cadherin), 17p (TP53 and OVCA1/2), and 22q12-qter (BAM22 and NF2). Furthermore, the whole q-arm of chromosome 10 was lost in five cases, indicating that not only PTEN but additional putative tumor suppressor genes may be involved in the development of glioblastomas, eg, DMBT1, FGFR2, and/or MXI1 that are located at the distal end of 10q. 37-39 Apart from PTEN, DMBT1, FGFR2, and MXI1 at 10q, TP53 at 17p13.1 and NF2 at 22q12, none of the known tumor oncogenes or suppressor genes mentioned above have yet been associated with astrocytoma tumorigenesis.

Tumor Proliferation, Genetics, and Prognosis

MIB-1 proliferation indices in our series were significantly lower in anaplastic astrocytomas than in glioblastomas corroborating previous investigations. 40,41 A significantly shorter survival was found for all high-grade astrocytomas with a MIB-1 proliferation index of >25% compared with tumors with a MIB-1 proliferation index of <25% reflecting a similar difference in outcome presented for MIB-1 proliferation cut-off levels of 11% 41 and 12%. 40 Although age was not prognostically significant, the three youngest children in this series which were <2 years of age were still alive 8, 27, and 107 months after diagnosis. The 1-, 2-, and 3-year survival rates overall in our series were 55, 33, and 21%, respectively, which are similar to the 2- and 3-year survival rates of 43% and 35 to 36% encountered elsewhere. 42-44 Outcome was significantly better for anaplastic astrocytomas with 1-, 2-, and 3-year survival rates of 70, 60, and 50%, respectively, compared with 46, 9, and 0% for pediatric glioblastomas.

When correlating prognosis with specific chromosomal aberrations, a significantly shorter survival among children with anaplastic astrocytomas showing gains of 1q compared to cases without this change could be found; this correlation could not be established for pediatric glioblastomas (Figure 2) ▶ . Although an association between TP53 mutation and a shorter progression-free survival has been proposed in one investigation on pediatric malignant gliomas, 45 no association between presence of TP53 mutation and patient survival was found in two series of adult glioblastomas; 8,46 in our study, the five children with −17p all died between 4 and 15 months after diagnosis. Correlations between prognosis, tumor dynamics and chromosomal imbalances have previously been presented for adult high-grade gliomas and consisted of more frequent gains of 12q14-21 and 19 among slower growing glioblastomas compared with gains of 6q16-qter, 13, and 20 among faster growing subgroup. 26 Another study found higher chemosensitivity, longer recurrence-free survival after chemotherapy, and longer overall survival among anaplastic oligodendrogliomas to be associated with loss of chromosomes 1p and 19q whereas CDKN2A gene deletions had a worse prognosis. 47 On the other hand, loss of the INK4a-ARF locus on chromosome 9p21 and loss of 14pARF expression was speculated to contribute to the highly malignant behavior and treatment resistance of adult high-grade astrocytomas; 48 loss of material on 9p, however, only affected two children with anaplastic astrocytomas, who were still alive at time of reporting, and one with glioblastoma who died after 12 months.

In conclusion, our results show that although there may be some common genetic steps in the malignant progression of both pediatric and adult astrocytomas there are also a number of nonrandom aberrations that have not been observed in adult high-grade astrocytomas, supporting a different genetic pathway and contradicting the notion that high-grade astrocytic tumors in children differ from those in adults by lacking consistent numerical and structural deviations. 10 Furthermore, gains of chromosomal material on 1q seem to be correlated with a worse prognosis among pediatric anaplastic astrocytomas but not glioblastomas. However, as these histological groups consisted of only 10 and 13 cases, respectively, this finding will have to be corroborated among a larger cohort.

Acknowledgments

This work is dedicated to the late Dr. K.H. Krähling as well as the unfortunate children included in this study and their parents. We thank Beate Schröder, Maria Leisse, Lydia Grote, Ulrike Neubert, and Willi Kramer for their invaluable help and skillful assistance; and Dr. Heinecke from the Institute of Medical Statistics and Biomathematics Münster for his help.

Footnotes

Address reprint requests to Christian H. Rickert, M.D., University of Münster, Institute of Neuropathology, Domagkstr. 19, D-48129, Münster, Germany. E-mail: rickchr@uni-muenster.de.

References

  • 1.Kaatsch P, Kaletsch U, Spix C, Michaelis J: Annual report 1998 German Childhood Cancer Registry. 1999. Lindner, Mainz
  • 2.Kleihues P, Cavenee WK: Tumours of the nervous system. World Health Organization Classification of Tumours. 2000, :pp 27-39 IARC Press, Lyon [Google Scholar]
  • 3.Rickert CH, Dockhorn-Dworniczak B, Simon R, Paulus W: Chromosomal imbalances in primary lymphomas of the central nervous system. Am J Pathol 1999, 155:1445-1451 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Bhattacharjee MB, Bruner JM: p53 protein in pediatric malignant astrocytomas: a study of 21 patients. J Neurooncol 1997, 32:225-233 [DOI] [PubMed] [Google Scholar]
  • 5.Biegel JA: Genetics of pediatric central nervous system tumors. J Pediatr Hematol Oncol 1997, 19:492-501 [DOI] [PubMed] [Google Scholar]
  • 6.Orellana C, Hernandez-Marti M, Martinez F, Castel V, Millan JM, Alvarez-Garijo JA, Prieto F, Badia L: Pediatric brain tumors: loss of heterozygosity at 17p and TP53 gene mutations. Cancer Genet Cytogenet 1998, 102:93-99 [DOI] [PubMed] [Google Scholar]
  • 7.Neumann E, Kalousek DK, Norman MG, Steinbok P, Cochrane DD, Goddard K: Cytogenetic analysis of 109 pediatric central nervous system tumors. Cancer Genet Cytogenet 1993, 71:40-49 [DOI] [PubMed] [Google Scholar]
  • 8.Rasheed BK, McLendon RE, Herndon JE, Friedman HS, Friedman AH, Bigner DD, Bigner SH: Alterations of the TP53 gene in human gliomas. Cancer Res 1994, 54:1324-1330 [PubMed] [Google Scholar]
  • 9.Agamanolis DP, Malone JM: Chromosomal abnormalities in 47 pediatric brain tumors. Cancer Genet Cytogenet 1995, 81:125-134 [DOI] [PubMed] [Google Scholar]
  • 10.Bigner SH, McLendon RE, Fuchs H, McKeever PE, Friedman HS: Chromosomal characteristics of childhood brain tumors. Cancer Genet Cytogenet 1997, 97:125-134 [DOI] [PubMed] [Google Scholar]
  • 11.Rasheed BK, Stenzel TT, McLendon RE, Parsons R, Friedman AH, Friedman HS, Bigner DD, Bigner SH: PTEN gene mutations are seen in high-grade but not in low-grade gliomas. Cancer Res 1997, 57:4187-4190 [PubMed] [Google Scholar]
  • 12.Sure U, Ruedi D, Tachibana O, Yonekawa Y, Ohgaki H, Kleihues P, Hegi ME: Determination of p53 mutations, EGFR overexpression, and loss of p16 expression in pediatric glioblastomas. J Neuropathol Exp Neurol 1997, 56:782-789 [PubMed] [Google Scholar]
  • 13.Cheng Y, Ng HK, Zhang SF, Ding M, Pang JC, Zheng J, Poon WS: Genetic alterations in pediatric high-grade astrocytomas. Hum Pathol 1999, 30:1284-1290 [DOI] [PubMed] [Google Scholar]
  • 14.Rey JA, Bello MJ: Cytogenetics. The Gliomas. edited by MS Berger, CB Wilson CB. Philadelphia, WB Saunders, 1999, pp 25–37
  • 15.Willert JR, Daneshvar L, Sheffield VC, Cogen PH: Deletion of chromosome arm 17p DNA sequences in pediatric high-grade and juvenile pilocytic astrocytomas. Genes Chromosom Cancer 1995, 12:165-172 [DOI] [PubMed] [Google Scholar]
  • 16.Schiffer D, Cavalla P, Di Sapio A, Giordana MT, Mauro A: Mutations and immunohistochemistry of p53 and proliferation markers in astrocytic tumors of childhood. Child’s Nerv Syst 1995, 11:517-522 [DOI] [PubMed] [Google Scholar]
  • 17.Louis DN, Rubio MP, Correa KM, Gusella JF, von Deimling A: Molecular genetics of pediatric brain stem gliomas. Application of PCR techniques to small and archival brain tumor specimens. J Neuropathol Exp Pathol 1993, 52:507-515 [DOI] [PubMed] [Google Scholar]
  • 18.Sung T, Miller DC, Hayes RL, Alonso M, Yee H, Newcomb EW: Preferential inactivation of the p53 tumor suppressor pathway and lack of EGFR amplification distinguish de novo high grade pediatric astrocytomas from de novo adult astrocytomas. Brain Pathol 2000, 10:249-259 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Di Tomaso E, Pang JC, Lam HK, Tian XX, Suen KW, Hui AB, Hjelm NM: Establishment and characterization of a human cell line from paediatric cerebellar glioblastoma multiforme. Neuropathol Appl Neurobiol 2000, 26:22-30 [DOI] [PubMed] [Google Scholar]
  • 20.Thiel G, Lozanova T, Vogel S, Kintzel D, Jänisch W, Witkowski R: Age-related nonrandom chromosomal abnormalities in human low-grade astrocytomas. Hum Genet 1993, 91:547-550 [DOI] [PubMed] [Google Scholar]
  • 21.Schröck E, Thiel G, Lozanova T, du Manoir S, Meffert MC, Jauch A, Speicher MR, Nürnberg P, Vogel S, Jänisch W, Donis-Keller H, Ried T, Witkowski R, Cremer T: Comparative genomic hybridization of human malignant gliomas reveals multiple amplification sites and nonrandom chromosomal gains and losses. Am J Pathol 1994, 144:1203-1218 [PMC free article] [PubMed] [Google Scholar]
  • 22.Harada K, Nishizaki T, Ozaki S, Kubota H, Ito H, Sasaki K: Intratumoral cytogenetic heterogeneity detected by comparative genomic hybridization and laser scanning cytometry in human gliomas. Cancer Res 1998, 58:4694-4700 [PubMed] [Google Scholar]
  • 23.Nishizaki T, Ozaki S, Harada K, Ito H, Arai H, Beppu T, Sasaki K: Investigation of genetic alterations associated with the grade of astrocytic tumor by comparative genomic hybridization. Genes Chromosom Cancer 1998, 21:340-346 [DOI] [PubMed] [Google Scholar]
  • 24.Maruno M, Yoshimine T, Muhammad AKMG, Ninomiya H, Kato A, Hayakawa T: Chromosomal aberrations detected by comparative genomic hybridization (CGH) in human astrocytic tumors. Cancer Let 1999, 135:61-66 [DOI] [PubMed] [Google Scholar]
  • 25.Kim DH, Mohapatra G, Bollen A, Waldmann FM, Feuerstein BG: Chromosomal abnormalities in glioblastoma multiforme tumors and glioma cell lines detected by comparative genomic hybridization. Int J Cancer 1995, 60:812-819 [DOI] [PubMed] [Google Scholar]
  • 26.Weber RG, Sommer C, Albert FK, Kiessling M, Cremer T: Clinically distinct subgroups of glioblastoma multiforme studied by comparative genomic hybridization. Lab Invest 1996, 74:108-119 [PubMed] [Google Scholar]
  • 27.Mohapatra G, Bollen AW, Kim DH, Lamborn K, Moore DH, Prados MD, Feuerstein BG: Genetic analysis of glioblastoma multiforme provides evidence for subgroups within the grade. Genes Chromosom Cancer 1998, 21:195-206 [PubMed] [Google Scholar]
  • 28.Schlegel J, Scherthan H, Arens N, Stumm G, Kiessling M: Detection of complex genetic alterations in human glioblastoma multiforme using comparative genomic hybridization. J Neuropathol Exp Neurol 1996, 55:81-87 [DOI] [PubMed] [Google Scholar]
  • 29.Jung V, Romeike BFM, Henn W, Feiden W, Moringlane JR, Zang KD, Urbschat S: Evidence of focal genetic microheterogeneity in glioblastoma multiforme by area-specific CGH on microdissected tumor cells. J Neuropathol Exp Neurol 1999, 58:993-999 [DOI] [PubMed] [Google Scholar]
  • 30.Ichimura K, Schmidt EE, Miyakawa A, Goike HM, Collins VP: Distinct patterns of deletion on 10p and 10q suggest involvement of multiple tumor suppressor genes in the development of astrocytic gliomas of different malignancy grades. Genes Chromosom Cancer 1998, 22:9-15 [DOI] [PubMed] [Google Scholar]
  • 31.Tohma Y, Gratas C, Biernat W, Peraud A, Fukuda M, Yonekawa Y, Kleihues P, Ohgaki H: PTEN (MMAC1) mutations are frequent in primary glioblastomas (de novo) but not in secondary glioblastomas. J Neuropathol Exp Neurol 1998, 57:684-689 [DOI] [PubMed] [Google Scholar]
  • 32.Fujisawa H, Reis RM, Nakamura M, Colella S, Yonekawa Y, Kleihues P, Ohgaki H: Loss of heterozygosity on chromosome 10 is more extensive in primary (de novo) than in secondary glioblastomas. Lab Invest 2000, 80:65-72 [DOI] [PubMed] [Google Scholar]
  • 33.Schlegel J, Merdes A, Stumm G, Albert FK, Forsting M, Hynes N, Kiessling M: Amplification of the epidermal-growth-factor-receptor gene correlates with different growth behaviour in human glioblastoma. Int J Cancer 1994, 56:72-77 [DOI] [PubMed] [Google Scholar]
  • 34.Miyakawa A, Ichimura K, Schmidt EE, Varmeh-Ziaie S, Collins VP: Multiple deleted regions on the long arm of chromosome 6 in astrocytic tumours. Br J Cancer 2000, 82:543-549 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Ino Y, Silver J, Blazejewski L, Nishikawa R, Matsutani M, von Deimling A, Louis DN: Common regions of deletion on chromosome 22q12.3-q13.1 and 22q13.2 in human astrocytomas appear related to malignancy grade. J Neuropathol Exp Neurol 1999, 58:881-885 [DOI] [PubMed] [Google Scholar]
  • 36.Büschges R, Weber RG, Actor B, Lichter P, Collins VP, Reifenberger G: Amplification and expression of cyclin D genes (CCDN1, CCDN2, CCDN3) in human malignant gliomas. Brain Pathol 1999, 9:435-443 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Mollenhauer J, Wiemann S, Scheurlen W, Korn B, Hayashi Y, Wilgenbus KK, von Deimling A, Poustka A: DMBT1, a new member of the SRCR superfamily, on chromosome 10q25.3–26.1 is deleted in malignant brain tumours. Nat Genet 1997, 17:32-39 [DOI] [PubMed] [Google Scholar]
  • 38.Wechsler DS, Shelly CA, Petroff CA, Dang CV: MXI1, a putative tumor suppressor gene, suppresses growth of human glioblastoma cells. Cancer Res 1997, 57:4905-4912 [PubMed] [Google Scholar]
  • 39.Fujisawa H, Kurrer M, Reis RM, Yonekawa Y, Kleihues P, Ohgaki H: Acquisition of the glioblastoma phenotype during astrocytoma progression is associated with loss of heterozygosity on 10q25-qter. Am J Pathol 1999, 155:387-394 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Pollack IF, Campbell JW, Hamilton RL, Martinez AJ, Bozik ME: Proliferation index as a predictor of prognosis in malignant gliomas of childhood. Cancer 1997, 79:849-856 [PubMed] [Google Scholar]
  • 41.Ho DM, Wong TT, Hsu CY, Ting LT, Chiang H: MIB-1 labeling index in nonpilocytic astrocytoma of childhood: a study of 101 cases. Cancer 1998, 82:2459-2466 [DOI] [PubMed] [Google Scholar]
  • 42.Duffner PK, Horowitz ME, Krischer JP, Friedmann HS, Burger PC, Cohen ME, Sanford RA, Mulhern RK, James HE, Freeman CR, Seidel FG, Kun LE: Postoperative chemotherapy and delayed radiation in children less than 3 years of age with malignant brain tumors. N Engl J Med 1993, 328:1725-1731 [DOI] [PubMed] [Google Scholar]
  • 43.Geyer JR, Finlay JL, Boyett JM, Wisoff J, Yates A, Mao L, Packer RJ: Survival of infants with malignant astrocytomas: a report from the Childrens Cancer Group. Cancer 1995, 75:1045-1050 [DOI] [PubMed] [Google Scholar]
  • 44.Heideman RL, Kuttesch J, Jr, Gajjar AJ, Walter AW, Jenkins JJ, Li Y, Sanford RA, Kun LE: Supratentorial malignant gliomas in childhood: a single institution perspective. Cancer 1997, 80:497-504 [DOI] [PubMed] [Google Scholar]
  • 45.Pollack IF, Hamilton RL, Finkelstein SD, Campbell JW, Martinez AJ, Sherwin RN, Bozik ME, Gollin SM: The relationship between TP53 mutations and overexpression of p53 and prognosis in malignant gliomas of childhood. Cancer Res 1997, 57:304-309 [PubMed] [Google Scholar]
  • 46.Newcomb EW, Cohen H, Lee SR, Bhalla SK, Bloom J, Hayes RL, Miller DC: Survival of patients with glioblastoma multiforme is not influenced by altered expression of p16, p53, EGFR, MDM2 or bcl-2 genes. Brain Pathol 1998, 8:655-667 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47.Cairncross JG, Ueki K, Zlatescu MC, Lisle DK, Finkelstein DM, Hammond RR, Silver JS, Stark PC, Macdonald DR, Ino Y, Ramsay DA, Louis DN: Specific genetic predictors of chemotherapeutic response and survival in patients with anaplastic oligodendrogliomas. J Natl Cancer Inst 1998, 90:1473-1479 [DOI] [PubMed] [Google Scholar]
  • 48.Newcomb EW, Alonso M, Sung T, Miller DC: Incidence of p14ARF gene deletion in high-grade adult and pediatric astrocytomas. Hum Pathol 2000, 31:115-119 [DOI] [PubMed] [Google Scholar]

Articles from The American Journal of Pathology are provided here courtesy of American Society for Investigative Pathology

RESOURCES