Microsatellite analysis of childhood brain tumors

Loss of heterozygosity at specific chromosomal locations has been taken as evidence of a tumor suppressor gene located in that area. We performed a genomic allelotyping study on 46 childhood brain tumors of different histopathological types in order to identify and confirm common areas of deletion in different tumor types. Two hundred microsatellite DNA probes equally distributed over the 22 autosomes were applied, covering the genome in steps of approximately 25 cM. Our results confirm frequent loss of heterozygosity of chromosome arms 9q, 10q, 11p, 11q, 16q, and 22q in high-grade gliomas, medulloblastomas, and ependymomas. In addition, we found a new region of loss on chromosome segment 2p21-23 affected predominantly in high-grade gliomas and medulloblastomas. Genes Chromosom Cancer 15:54–63 (1996). © 1996 Wiley-Liss, Inc.     

Chromosome studies in two human brain tumors

The cytogenetic findings based on G- and C-banding in two human brain tumors (a meningioma and an astrocytoma) are reported. Both tumors were characterized by hypodiploid modal numbers (45 and 40 chromosomes, respectively), chromosome 22 abnormalities, and the presence of several markers. This observation supports the hypothesis of the association of No. 22 chromosome abnormalities with tumors of the brain.     

Chromosome analysis of a brain malignant lymphoma cell line

Chromosome studies of a malignant lymphoma cell line derived from the brain were made by Q- and G-banding techniques. The modal number of chromosomes was 45. Complex structural rearrangements were present, but the 14q+ marker chromosome frequently seen in malignant lymphomas was not identified in the cell line. The main karyotype in cells analyzed was 45, X, -Y, del (2) (q21q23), t (3;?) (p25;?), t (p12;?), -8, 11q+, 18q+, +mar. Absence of the 14q+ may be explained by: firstly, clones which possessed 14q+ marker chromosome in brain tumor cells may have been selected out with increasing culture time and repeated passages; or secondly, the presence of the 14q+ marker chromosome depends on the type of lymphoma.     

Kidney tumors in childhood

Types of renal tumors arising in children are different from those occurring in adults. Nephroblastoma is the most common (85%) with a clinical outcome which has dramatically improved in the last 30 years. Current classifications are aimed at better adaptation of treatment to each individual case, reducing iatrogenic complications without impairing total cure. Amongst entities which have been recently described or are better known we can find juvenile carcinoma associated with Xp11.2 translocation, renal medullary carcinoma, metanephric tumors, etc. Role of molecular cytogenetics is increasing for classification (and treatment) and this should always be kept in mind when dealing a fresh specimen of childhood renal tumor.     

Chromosome studies in eleven colorectal tumors

Cytogenetic analysis is presented on seven freshly derived colorectal tumors and four established cell lines (SW 742, SW 480, SW 948, and HT 29). No chromosome change was common to all tumors, although previous nonrandom findings were confirmed. Single chromosome abnormalities were identified in two cases, 47,XX,+i(7p) and 46,XX,-17,+der(17),t(17;?)(p;?), and their relevance to tumor origin and development is discussed. The association of i(8q) with tumors of the rectosigmoidal region is confirmed, and it is suggested that other rearrangements involving loss of 8p may have the same association. Abnormalities resulting in loss of 20p and duplication of 20q, not previously reported as a nonrandom change, were seen in seven out of 11 cases.     

Survivors of childhood brain tumors: behavioral,emotional, and social adjustment

This paper reviews the literature on the psychological adjustment and quality of life in children who survive brain tumors. A total of 31 studies were reviewed. Findings are discussed in terms of the rates of general psychological adjustment, internalizing behavior problems, externalizing behavior problems, social competence, correlates or predictors of adjustment, and quality of life among survivors. Although these survivors appear to be at risk for compromised social competence and long-term quality of life, reports in the literature on rates of psychological adjustment in this population vary widely. Limitations in the current literature are discussed including inadequate assessment techniques, lack of appropriate comparison groups, and small sample sizes. Directions for future research are offered.     

ADAM23 methylation and expression analysis in brain tumors

The ADAMs comprises a family of cell surface proteins with putative roles in cell–cell and/or cell–matrix interactions and in protease activities. In this work, we have examined the expression level and the methylation status of the 5′ upstream region of the adhesion molecule ADAM23 in two brain tumor cell lines (A172 and T98G) as well as in three primary brain tumors (one grade II astrocytoma and two meningiomas) and 15 glioblastoma xenografts. Using bisulfite sequencing we verified that the percentage of methylated dinucleotides is higher in T98G when compared to A172 and that methylation significantly correlates with ADAM23 mRNA and protein expression. However, we were unable to detect methylation and down-regulation of the ADAM23 gene in brain tumors. Together, these results indicate that ADAM23 down-regulation by methylation in brain tumors is a rare event and it may help explain why brain tumor metastases are rarely found elsewhere in the body.     

Chromosome abnormalities in two benign adipose tumors

Two histologically benign adipose tumors were found to have clonal karyotypic changes. Del(4), del(6), and inv(13) were present in a fibrolipoma, and t(7;8) in a lipoblastoma. Additional studies are needed of the frequency and malignant potential of lipomas with cytogenetic abnormalities.     

Gains and losses of DNA sequences in childhood brain tumors analyzed by comparative genomic hybridization

Primary central nervous system neoplasms are the most common solid tumors in children. Genetic changes underlying childhood brain-tumor development and progression are incompletely characterized. To get an overview of the genetic events leading to the development of brain tumors and to identify chromosomal regions that may contain genes important in brain-tumor progression, we employed a comparative genomic hybridization technique. Twenty-four pediatric primary brain tumors were analyzed in this study. DNA copy number changes were observed in most of the samples (79%), and almost all chromosomes were involved. The total number of genetic aberrations (copy-number gains and losses per tumor) was significantly higher in the cerebellar primitive neuroectodermal tumor subgroup than in the gliomas. The high-grade tumors had more DNA changes than did the low-grade tumors. The most often gained chromosomes were: 6q (45%), 4q (34.5%), and chromosome 1 (24% of the cases). The minimal common regions involved in DNA gains were narrowed down to 6q14-16 and 4q26-28. Losses of a specific chromosome (partly or as a whole) occurred on average in 7% of the cases. Chromosomal regions that were most often lost included chromosome 1 (17%), chromosome 16 (17%), and chromosome 2 (14%). These findings suggest that genes localized to these minimal common chromosomal regions play a role in the tumorogenesis of childhood brain tumors. Our results indicate: (1) a great degree of genomic imbalance in these tumors; (2) that a high number of aberrations correlate with aggressive tumor biology; (3) and that nonrandom genetic changes may be associated with particular tumor types.     

Diagnostic pitfalls in solid childhood tumors

Differential diagnosis of round and spindle cell type tumors in childhood is difficult. Diagnosis can be facilitated by additional immunohistochemical analysis (case 1) or detection of characteristic histological patterns (case 2). Rapid growth is not an exclusive feature of malignant tumors, but can also be observed in benign tumors and tumor-like conditions of young patients (case 3).     

Therapy associated changes in childhood tumors

Contemporary treatment regimens for the common solid tumors of childhood have led to increased numbers of post-treatment pathologic specimens from survivors. Current therapeutic strategies for childhood cancers in North America require an accurate pathologic diagnosis and stratify patients based on combinations of clinical, biological, and pathologic features. In several tumor systems, the pathologic response to therapy also modifies the treatment regimen. Accurate pathologic interpretation of such specimens is critical in providing useful prognostic information for therapeutic decisions. Standardized handling of post-therapy pathologic specimens, appropriate use of molecular and genetic studies, consideration of the differential diagnoses, and assessment of the potential biologic significance of therapy-induced pathologic changes are, therefore, critical for patient management and determination of treatment protocols.