Chromosome 7 abnormalities are common in chordomas

Chordomas are malignant bone tumors most often located in the axial skeleton. The estimated 5-year patient survival rate is between 50 and 80%. The cytogenetic and molecular genetic features of chordomas are largely unknown but, from what can be seen, appear to be complex. Near-diploid karyotypes have been detected by G-banding analysis, and comparative genomic hybridization (CGH) has revealed losses of or from chromosome arms 1p and 3p, as well as partial or whole copy number gains of chromosomes 7 and 20. We provide additional molecular cytogenetic information about six sacral chordomas examined by CGH and interphase fluorescence in situ hybridization (IP-FISH). By CGH, gains of chromosomal areas 1q23 approximately q24 (three tumors), 7p21 approximately p22 (three tumors), 7q (four tumors), and 19p13 (three tumors), as well as loss of chromosomal segment 9p22 approximately p23 (three tumors), were the most frequently observed imbalances. These results are concordant with earlier CGH data, although loss of or from chromosome arms 1p and 3p was not found as frequently in this series; both were detected in only one tumor. IP-FISH confirmed the CGH findings and showed that chromosome 7 was polysomic in four of the tumors. All these samples had trisomic and tetrasomic clones for chromosome 7, and two of them had pentasomic clones as well.     

Expression of the HMGA2-LPP fusion transcript in only 1 of 61 karyotypically normal pulmonary chondroid hamartomas

We present the results of a comparative genomic hybridization (CGH) analysis of three meningeal solitary fibrous tumors (SFT). One case showed loss of chromosome 3 and two tumors had deletions of the region 3p21-p26. Other chromosomal losses included 4p15, 8q22-q24, 10, 11q14-q25, 17q11- q23, 20, and 21 in one case each. In addition, there were gains of 18p11-p13 in one case, and 1p11-p36 and 20q11-q13 in another. To our knowledge, there are no previous CGH or cytogenetic data on meningeal SFT, and loss of material on chromosome 3 has not been described in SFT at other sites. Our findings are discussed in relation to published molecular genetic and cytogenetic data on meningioma and hemangiopericytoma, the two lesions with which meningeal SFT are most likely to be confused.     

Characterization of large chromosome markers in a malignant fibrous histiocytoma by spectral karyotyping, comparative genomic hybridization (CGH), and array CGH

In this study, we characterized the chromosomal composition of an intra-abdominal soft tissue sarcoma diagnosed as a malignant fibrous histiocytoma (MFH). By applying a combination of spectral karyotyping, G-banding, and comparative genomic hybridization (CGH), this case was shown to carry large chromosome markers with material mainly from chromosomes 6 and 8. Further characterization of this unique tumor revealed high-level amplifications at the 6q21 approximately q23, 8p21 approximately pter, 8q24 approximately qter, and 12q13 approximately q21 regions. Using array CGH, these amplified regions were found to include MASL1 in 8p, as well s MDM2 and CDK4 in 12q, which have been shown to be amplified in MFH. Similarly, gains of 6q and 8q have also been seen in MFH. In conclusion, our study demonstrates the occurrence of large chromosome markers in MFH and suggests that the regions 6q21 approximately q23, 8p21 approximately pter, 8q24 approximately qter, and 12q13 approximately q21 might harbor oncogenes that could play a role in MFH's tumorigenesis. In addition, gain of 12q13 approximately q21, which is typical of well-differentiated liposarcoma, may also occur in MFH, supporting the previously suggested overlap in genetic etiologies between these two tumor types.     

Comparative genomic hybridization analysis of benign and invasive male breast neoplasms

Comparative genomic hybridization (CGH) analysis was performed for the identification of chromosomal imbalances in two benign gynecomastias and one malignant breast carcinoma derived from patients with male breast disease and compared with cytogenetic analysis in two of the three cases. CGH analysis demonstrated overrepresentation of 8q in all three cases. One case of gynecomastia presented gain of 1p34.3 through pter, 11p14 through q12, and 17p11.2 through qter, and loss of 1q41 through qter and 4q33 through qter. The other gynecomastia presented del(1)(q41) as detected by both cytogenetic and CGH analysis. CGH analysis of the invasive ductal carcinoma confirmed a gain of 17p11.2 through qter previously detected by cytogenetic analysis. These regions showed some similarity in their pattern of imbalance to the chromosomal alterations described in female and male breast cancer.     

Comprehensive analysis of genomic alterations in gliosarcoma and its two tissue components

Gliosarcoma is a variant of glioblastoma multiforme characterized by two components displaying gliomatous or sarcomatous differentiation. We investigated 38 gliosarcomas for aberrations of tumor-suppressor genes and proto-oncogenes that are commonly altered in glioblastomas. Amplification of CDK4, MDM2, EGFR, and PDGFRA were found in 11% (4/35), 8% (3/38), 8% (3/38), and 3% (1/35) of the tumors, respectively. Nine of 38 gliosarcomas (24%) carried TP53 mutations. PTEN mutations were identified in 45% (9/20) of the investigated tumors. Twenty gliosarcomas were analyzed by comparative genomic hybridization (CGH). Chromosomal imbalances commonly detected were gains on chromosomes 7 (15/20; 75%), X (4/20; 20%), 9q, and 20q (3/20, 15% each); and losses on chromosomes 10 and 9p (7/20, 35% each), and 13q (3/20, 15%). Five different high-level amplifications were mapped to 4q12-q21 (1 case), 6p21 (1 case), 7p12 (2 cases), proximal 12q (4 cases), and 14q32 (1 case) by CGH. Southern blot and/or differential PCR analyses identified amplification of PDGFRA (4q12), CCND3 (6p21), EGFR (7p12), CDK4 (12q14) and/or MDM2 (12q14.3-q15), and AKT1 (14q32.3) in the respective tumors. Separate analysis of the gliomatous and sarcomatous components of eight gliosarcomas by CGH after microdissection and universal DNA amplification revealed that both components shared 57% of the chromosomal imbalances detected. Taken together, our data indicate that the genomic changes in gliosarcomas closely resemble those found in glioblastomas. However, the number of chromosomes involved in imbalances in gliosarcomas was significantly lower than that in glioblastomas, indicating a higher genomic stability in gliosarcomas. In addition, we provide further support for the hypothesis that the gliomatous and sarcomatous components are derived from a single precursor cell clone, which progressed into subclones with distinct morphological features during tumor evolution. According to our data, gain/amplification of genes on proximal 12q may facilitate the development of a sarcomatous phenotype.     

Intratumoral heterogeneity in breast carcinoma revealed by laser-microdissection and comparative genomic hybridization

To evaluate the potential cytogenetic heterogeneity in breast carcinoma, several small cell groups (each consisting of 20 to 50 cells) were investigated within paraffin sections. By laser-microdissection, three to seven cell groups were taken per case. The DNA was amplified by degenerate oligonucleotide primed PCR (DOP-PCR), and the samples were analyzed by CGH for chromosomal gains and losses. Two ductal invasive breast carcinomas, one of them with two lymphnode metastases, were investigated. To compare the results from the small samples, CGH was also performed on DNA isolated from the tumorous regions of three to five serial sections (10⁷ to 10⁶ cells). The aberrations observed in the microdissected tumor samples were multiple and involved up to 14 different chromosomal or subchromosomal regions. The most frequent changes were gains on chromosomes 12q (14/20) and 20q (16/20), and loss on 13q (12/20). Some aberrations have rarely been detected (e.g., loss on 2p, gain on 8q). Comparing chromosomal imbalances in primary tumors and lymph node metastases, more consistent changes were found between the primary tumor and its corresponding metastases than between both primary tumors. The laser-microdissected samples in general showed more chromosomal aberrations than DNA isolated from several tumor sections. Our CGH results were confirmed by fluorescence in situ hybridization (FISH) for the chromosomal regions of centromere 1 and 20, and 20q13. In addition, microsatellite analyses on 31 samples confirmed our CGH findings for selected chromosome regions 2p and 11q. It can be concluded that there is a distinct intratumoral heterogeneity in primary breast tumors as well as in the corresponding lymph node metastases. The combination of microdissection and CGH enabled us to detect cytogenetic aberrations from important clones which are missed when analyzing DNA extracted from large cell numbers.     

Combined comparative genomic hybridization and genomic microarray for detection of gene amplifications in pulmonary artery intimal sarcomas and adrenocortical tumors

Identification of gene amplifications in human tumors is important for the understanding of tumorigenesis and may lead to discovery of diagnostic and prognostic markers. In this study, we used a microarray-based comparative genomic hybridization (CGH) technique, combined with conventional CGH, to identify gene amplifications in 43 tumors including eight pulmonary artery intimal sarcomas and 35 adrenocortical tumors. Conventional CGH revealed gains or amplifications of 12q13-q15 in six sarcomas and in two adrenocortical carcinomas. Using microarrays, we demonstrated that, among genes located on 12q13-q15, SAS/CDK4 were amplified in six sarcomas, and MDM2 and GLI in five and four sarcomas, respectively. The two adrenocortical tumors showed coamplifications of SAS/CDK4 and MDM2. Furthermore, PDGFRA (located on 4q12) amplification was identified in five sarcomas. Our data demonstrate: (1) amplifications of SAS/CDK4, MDM2, GLI, and PDGFRA are strongly associated with the tumorigenesis of pulmonary artery intimal sarcomas, whereas SAS/CDK4 and MDM2 coamplification may contribute to the progression of adrenocortical tumors; (2) microarray-based CGH is a useful tool for simultaneous detection of multiple gene amplifications, with a high sensitivity and resolution compared to that of conventional CGH.     

High-resolution array comparative genomic hybridization analysis of human bronchial and salivary adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a rare but distinctive tumor. Oligonucleotide array comparative genomic hybridization has been applied for cataloging genomic copy number alterations (CNAs) in 17 frozen salivary or bronchial tumors. Only four whole chromosome CNAs were found, and most cases had 2-4 segmental CNAs. No high level amplification was observed. There were recurrent gains at 7p15.2, 17q21-25, and 22q11-13, and recurrent losses at 1p35, 6q22-25, 8q12-13, 9p21, 12q12-13, and 17p11-13. The minimal region of gain at 7p15.2 contained the HOXA cluster. The minimal common regions of deletions contained the CDKN2A/CDKN2B, TP53, and LIMA1 tumor suppressor genes. The recurrent deletion at 8q12.3-13.1 contained no straightforward tumor suppressor gene, but the MIRN124A2 microRNA gene, whose product regulates MMP2 and CDK6. Among unique CNAs, gains harbored CCND1, KIT/PDGFRA/KDR, MDM2, and JAK2. The CNAs involving CCND1, MDM2, KIT, CDKN2A/2B, and TP53 were validated by FISH and/or multiplex ligation-dependent probe amplification. Although most tumors overexpressed cyclin D1 compared with surrounding glands, the only case to overexpress MDM2 had the corresponding CNA. In conclusion, our report suggests that ACC is characterized by a relatively low level of structural complexity. Array CGH and immunohistochemical data implicate MDM2 as the oncogene targeted at 12q15. The gain at 4q12 warrants further exploration as it contains a cluster of receptor kinase genes (KIT/PDGFRA/KDR), whose products can be responsive to specific therapies.     

Comparative genomic and in situ hybridization of germ cell tumors of the infantile testis

Chromosomal information on germ cell tumors of the infantile testis, ie, teratomas and yolk sac tumors, is limited and controversial. We studied two teratomas and four yolk sac tumors using comparative genomic hybridization (CGH) and in situ hybridization. No chromosomal anomalies were found in the teratomas by any of the methods, not even after CGH on microdissected tumor cells. All yolk sac tumors showed aneuploidy, loss of parts of 4q and 6q, and gain of parts of 20q. Underrepresentation of parts of 8q and overrepresentation of parts of 3p, 9q, 12p, 17, 19q, and 22 were detected in most cases. In addition, one recurrent yolk sac tumor after a sacral teratoma was studied, showing a highly similar pattern of imbalances. While CGH demonstrated loss of 1p36 in one testicular yolk sac tumor, in situ hybridization revealed loss of this region in all yolk sac tumors. High-level amplification of the 12q13-q14 region was found in one yolk sac tumor. MDM2, of which the encoding gene maps to this chromosomal region, was found in all cases using immunohistochemistry, whereas no p53 could be detected. Accordingly, no mutations within exons 5 to 8 of the p53 gene were observed. These data prove the absence of gross chromosomal aberrations in teratomas of the infantile testis and show a characteristic pattern of gains and losses in the yolk sac tumors. Besides confirmation of previously found anomalies, recurrent losses of 1p21-31 and 4q23-33 and gains of 9q34 and 12p12-13 have not been reported before. While genetic inactivation of p53 seems unimportant in the pathogenesis of these tumors, biochemical inactivation by MDM2 might be involved. These data support the existence of three entities of germ cell tumors of the human testis: teratomas and yolk sac tumors of infants, seminomas and nonseminomas of adolescents and young adults, and spermatocytic seminomas of the elderly, each with its own specific pathogenesis.     

Pancreatic acinar carcinoma shows a distinct pattern of chromosomal imbalances by comparative genomic hybridization

Pancreatic acinar cell carcinoma (PAC) is a rare pancreatic tumor for which no information about chromosomal anomalies is available. We examined six primary PACs by comparative genomic hybridization (CGH). All cases showed chromosomal changes. A total of 106 gains and 48 losses was detected. Consensus regions of gain were identified on chromosomes 1, 12, and X: 1q21 in four cases, 1q42 in three cases, 12p11.2 in four cases, and Xq12-21 in three cases. Recurrent losses were found at 16p13.2-p13.1 in three cases and at 16q23 in three cases. To verify these chromosomal imbalances, microsatellite analysis of matched normal and tumor DNA was performed using PCR-amplified markers for chromosomes 1, 12, and 16 in the regions showing nonrandom gains or losses. This analysis showed allelic imbalances in tumor DNA consistent with the CGH profiles. Our CGH study suggests that PAC shows a characteristic pattern of chromosomal alterations, involving gain at 1q, 12p, and Xq and loss of sequences at 16p and 16q. This pattern appears unique among solid tumors and is markedly different from that detected in pancreatic ductal carcinomas by the same technique. This suggests that PAC tumorigenesis involves different molecular pathways than those involved in the more common pancreatic ductal tumors. Genes Chromosomes Cancer 28:294-299, 2000.     

Comparative genomic hybridization analysis of abnormalities in chromosome 21 in childhood osteosarcoma

Osteosarcomas (OS) are aggressive tumors of the bone and often have a poor prognosis. The tumors exhibit karyotypes with a high degree of complexity, which has made it difficult to determine whether any recurrent chromosomal aberrations characterize OS. To address inherent difficulties associated with classical cytogenetic analysis, comparative genomic hybridization (CGH) was applied to OS tissue. Forty-one pediatric OS specimens were analyzed by a CGH technique: 24 female and 17 male patients, with a median age of 12 years and 4 months. Chromosomal abnormalities were highly diverse and variable, including gains of chromosome 1p, 2p, 3q, 5q, 5p, and 6p and losses of 14q (50% in 14q11.2), 15q, and 16p. A high level of losses of chromosome 21 was present (26/41 cases; P = 0.008), most often loss of the 21q11.2 approximately 21 region. These novel findings in chromosome 21 of pediatric OS tumors suggest that specific sequences mapping to these chromosomal regions are likely to play a role in the development of OS.     

Detection of chromosomal DNA gains and losses in testicular germ cell tumors by comparative genomic hybridization

To extend the results of conventional cytogenetic analysis of testicular germ cell tumors (TGCTs), we applied the new molecular cytogenetic method of comparative genomic hybridization (CGH), which enables the detection of chromosomal imbalances without the need for dividing cells. DNA from II TGCTs was studied by CGH. In all tumors examined, gain of 12p, mostly of the whole p arm, could be demonstrated. However, in three tumors, an amplification of 12p material restricted to the chromosomal bands 12p11.2-p12.1 was found. Further fluorescence in situ hybridization (FISH) analysis using a yeast artificial chromosome (YAC) that was previously mapped to that region revealed multiple copies of that chromosomal segment in interphase nuclei of these tumors. This finding is an important clue to the localization of candidate protooncogenes at 12p involved in TGCTs. Gains of small chromosomal regions at 2p, 4q, 6p, and 19p were also detected recurrently. Furthermore, gains of chromosomes 8, 14, 21, and X as well as loss of chromosome 13 were frequent findings. In conclusion, CGH provides new insights into genetic alterations of TGCTs. By using CGH, chromosomal subregions could be identified that may harbor genes involved in the pathogenesis of this malignancy. Genes Chromosom Cancer 17:78–87 (1996). © 1996 Wiley-Liss, Inc.     

Genetic diagnosis by comparative genomic hybridization in adult de novo acute myelocytic leukemia

A total of 127 adult de novo acute myelocytic leukemia (AML) patients were analyzed by comparative genomic hybridization (CGH) at diagnosis. Conventional cytogenetic analysis (CCA) showed a normal karyotype in 45 cases and an abnormal karyotype in 56 cases; in the remaining cases, CCA either failed to yield sufficient metaphase cells (19/26) or was not done (7/26). Abnormal CGH profiles were identified in 39 patients (30.7%). DNA copy number losses (61%) were high compared to gains (39%), whereas partial chromosome changes (76%) were more common than whole chromosomes changes (24%). Recurrent losses were detected on chromosomes 7, 5q (comprising bands 5q15 to 5q33), 7q (7q32 approximately q36), 16q (16q13 approximately q21), and 17p, and gains were detected on chromosomes 8, 22, and 3q (comprising bands 3q26.1 approximately q27). Furthermore, distinct amplifications were identified in chromosome regions 21q, 13q12 approximately q13, and 13q21.1. No cryptic recurrent chromosomal imbalances were identified by CGH in cases with normal karyotypes. The concordance between CGH results and CCA was 72.5%. In the remaining cases, CGH gave additional information compared to CCA (20%) and partially failed to identify the alterations previously detected by CCA (7.5%). The majority of discrepancies arose from the limitations of the CGH technique, such as insensitivity to detect unbalanced chromosomal changes when occurring in a low proportion of cells. CGH increased the detection of unbalanced chromosomal alterations and allowed precise defining of partial or uncharacterized cytogenetical abnormalities. Application of the CGH technique is thus a useful complementary diagnostic tool for CCA in de novo AML cases with abnormal karyotypes or with unsuccessful cytogenetics.     

Widespread chromosomal abnormalities in high-grade ductal carcinoma in situ of the breast. Comparative genomic hybridization study of pure high-grade DCIS

For a variety of technical reasons it is rarely possible to study cytogenetic abnormalities in ductal carcinoma in situ (DCIS) using traditional techniques. However, by combining molecular biology and computerized image analysis it is possible to carry out cytogenetic analyses on formalin-fixed, paraffin-embedded tissue, using comparative genomic hybridization (CGH). The purpose of this study was to identify the prevalence of chromosomal amplifications and deletions in high-grade DCIS and to look specifically for unique or consistent abnormalities in this pre-invasive cancer. Twenty-three cases of asymptomatic, non-palpable, screen-detected, high-grade DCIS were examined using CGH on tumour cells obtained from histology slides. All cases showed chromosomal abnormalities. A wide variety of amplifications and deletions were spread across the genome. The most frequent changes were gains of chromosomes 17 (13 of 23), 16p (13 of 23), and 20q (9 of 23) and amplifications of 11q13 (22 of 23), 12q 24.1–24.2 (12 of 23), 6p21.3 (11 of 23), and 1q31-qter (6 of 23). The most frequent deletions were on 13q 21.3–q33 (7 of 23), 9p21 (4 of 23), and 6q16.1 (4 of 23). These findings indicate that high-grade DCIS is, from a cytogenetic viewpoint, an advanced lesion. There was no absolutely consistent finding in every case, but amplification of 11q13 was found in 22 of the 23 cases. The precise significance of this is unknown at present. This region of chromosome 11q harbours a number of known oncogenes, including cyclinD1 and INT2. It is likely that many of these findings are the result of accumulated chromosomal abnormalities, reflecting an unstable genome in established malignancy. Copyright © 1999 John Wiley & Sons, Ltd.     

Comparative genomic hybridization study of placental site trophoblastic tumour: a report of four cases.

Placental site trophoblastic tumour (PSTT) is a neoplastic proliferation of the implantation intermediate trophoblast. Although clinicopathological studies are not uncommon in case reports or small series, molecular and genetic studies are quite limited. Four archived cases of PSTT were successfully analysed by comparative genomic hybridization (CGH) in this study. Regional chromosomal gains were observed in two cases. One case showed chromosomal gains in the regions of 19p13.2, 21q11-21 and 22q12. The second case demonstrated a single regional chromosomal gain involving 21q21. No chromosomal loss is observed. The remaining two cases showed a balanced CGH profile without detectable chromosomal gain or loss. In summary, although chromosomal alterations detectable by CGH are not common, rare chromosomal gains do occur in PSTT. The recurrent chromosomal gain involving chromosomal 21q observed in two of our cases deserves additional studies to ascertain whether it carries any pathobiological significance.     

Analysis of chromosomal copy number changes and oncoprotein expression in primary central nervous system lymphomas: frequent loss of chromosome arm 6q

Primary central nervous system lymphoma (PCNSL) is a rare disease. A small number of cytogenetic studies of PCNSL have been conducted and several reports have been published on associated molecular and protein expression data. We combined these approaches in a series of eight PCNSL cases, analyzing the chromosomal abnormalities using comparative genomic hybridization (CGH), testing for Epstein Barr virus (EBV) involvement by in situ hybridization for EBER, assessing expression of p53, Bcl-2, Bcl-6 and CD10 by means of immunohistochemistry, and screening for mutations of the TP53 gene by DGGE. TP53 gene mutations and EBV expression were not detected. Most of the cases showed p53, Bcl-6 and Bcl-2 protein expression. CGH revealed DNA copy number changes in all eight cases. The most frequent changes were gains of chromosome 12 (63%), chromosome 18 (50%) and 20q (38%), and loss of chromosome arm 6q (75%). No correlation between protein expression and chromosomal abnormalities was found in these eight cases. Although gains of chromosome 12, 18 and 20q and loss of 6q have also been reported in systemic diffuse large B-cell lymphomas, the frequency of 6q deletion is clearly higher in PCNSL. This creates a similarity to primary lymphomas of the testes that also frequently have deletions of 6q. This suggests that suppressor genes located on chromosome 6q may play a role in the development of lymphomas at immunoprivileged sites, like the CNS.     

Novel genomic imbalances in B-cell splenic marginal zone lymphomas revealed by comparative genomic hybridization and cytogenetics

Splenic marginal zone lymphoma (SMZL) has recently been recognized in the World Health Organization classification of hematological diseases as distinct type of non-Hodgkin's lymphoma. In contrast to the well-established chromosomal changes associated with other B-cell non-Hodgkin's lymphoma, few genetic alterations have been found associated with SMZL. The aim of our study was to analyze by comparative genomic hybridization (CGH) the chromosomal imbalances in 29 patients with SMZL and to correlate these findings with clinical and biological characteristics and patient outcome. In 21 cases, cytogenetic studies were simultaneously performed. Most of the patients (83%) displayed genomic imbalances. A total of 111 DNA copy number changes were detected with a median of four abnormalities per case (range, 1 to 12). Gains (n = 92) were more frequent than losses (n = 16), while three high-level amplifications (3q26-q29, 5p11-p15, and 17q22-q25) were observed. The most frequent gains involved 3q (31%), 5q (28%), 12q and 20q (24% each), 9q (21%), and 4q (17%). Losses were observed in 7q (14%) and 17p (10%). SMZL patients with genetic losses had a shorter survival than the remaining SMZL patients (P < 0.05). In summary, chromosomal imbalances in regions 3q, 4q, 5q, 7q, 9q, 12q, and 20q have been detected by CGH in SMZL. Patients with SMZL displaying genetic losses by CGH had a short survival.     

Chromosomal alterations in early stages of malignant mesotheliomas

In a case of a 67-year-old man with two different early stages of a predominantly epithelioid mesothelioma (“mesothelioma in situ”, “early-stage mesothelioma”), chromosomal imbalances were determined by comparative genomic hybridisation (CGH), a molecular cytogenetic technique to detect chromosomal gains and losses in tumour cells. In the case of the mesothelioma in situ cells, nine different chromosomal alterations could be detected (losses on 3p, 5q, 6q, 8p, 9p, 15q, 22q, Y; gain on 7q), whereas the early-stage mesothelioma showed the same defects except for the gain on 7q. The simultaneous losses of 6q, 9p and 22q, as well as other chromosomal regions, correlate well with the most common defects previously found in 90 cases of more-advanced-stage mesotheliomas using CGH. These data demonstrate that initial chromosomal defects in early stages of mesotheliomas can be detected by conventional CGH in combination with laser microdissection. The molecular cytogenetic findings support the histological diagnosis of a pleural mesothelioma. The surprisingly high number and extent of genomic alterations found in the examined case probably reflects the genomic instability in the tumour cells and indicates a “genetic chaos” even in earlier stages of malignant mesotheliomas.     

Comparative genomic hybridization analysis of a pleuropulmonary blastoma

Pleuropulmonary blastoma (PPB) is a rare, aggressive dysontogenetic tumor of childhood. We report the comparative genomic hybridization (CGH) study performed on a case of PPB in a 3-year-old-boy. The tumor was characterized by several chromosomal imbalances. Gains observed affected regions: 1q12-q23, 3q23-qter, 8pter-q24.1, 9p13-q21, 17p12-p11, 17q11-q22, 17q23-q25, 19pter-p11, and 19q11-q13.3. Whole chromosome gains were detected at 2 and 7. Loss of genetic material was found at regions: 6q13-qter, 10pter-p13, 10q22-qter, and 20p13. To our knowledge, there have been no CGH reports on PPB, but it is interesting to note that 1) the alterations found confirm previous cytogenetic reports describing gains of chromosomes 2 and 8 as recurrent abnormalities in this type of tumor, suggesting that a gene or genes of putative relevance in PPB pathogenesis are mapped at 8p11-p12, and 2) the CGH profile of this case is very similar to those observed in embryonal rhabdomyosarcomas, in which gains of 2 or 2q, 7 or 7q, and 8 or 8p and loss of 10q22-qter are consistently found. This finding supports the hypothesis that PPB may be tumorigenetically related with embryonal rhabdomyosarcoma.     

Analysis of selected oncogenes (AKT1, FOS, BCL2L2, TGFbeta) on chromosome 14 in granulosa cell tumors (GCTs): a comprehensive study on 30 GCTs combining comparative genomic hybridization (CGH) and fluorescence-in situ-hybridization (FISH)

In previous studies, we have demonstrated a number of cytogenetic alterations in granulosa cell tumors (GCTs), especially on chromosomes X, 12, 14, and 22. However, little is known about specific loci on 14q, which could play an important role in tumor pathology. Therefore, we assessed four important genes in 30 GCTs using fluorescence-in situ-hybridization (FISH). Comparative genomic hybridization (CGH) was performed on paraffin-embedded material. Then, we applied FISH with gene-specific DNA probes for AKT1 (14q32.32), FOS (14q24.3), BCL2L2 (14q11.2-q12), and TGFbeta3 (14q24), and tried to find a correlation between CGH, FISH, tumor stage, and survival. In CGH, 7 of 30 cases (23.3%) showed complete gains on chromosome 14. FISH of the four loci revealed gains of hybridization signals in 8 of 30 cases (26.6%), indicating trisomy of the whole chromosome arm. The same aberration was detected by FISH in 2 of 30 cases (6.6%), which were negative using CGH. One case (1 of 30; 3.3%) was found to have a gain on chromosome 14 by CGH, which could not be confirmed by FISH. A correlation with tumor stage or survival could not be established. Our results suggest that GCTs may be characterized by trisomy of chromosome 14. A specific oncogene that could play a particular role in the tumorigenesis of GCTs was not identified on chromosome 14.