Surgically treated patients with axial and peripheral Ewing's sarcoma family of tumours: A population based study in Finland during 1990-2009

BACKGROUND

The surgical treatment of Ewing's sarcoma family tumours (ESFTs) is challenging especially with axial tumours. The aim of the study was to analyse surgical treatment and outcome in a nationwide, population-based material consisting of surgically treated axial and peripheral ESFTs of bone and soft tissue.

METHODS

The data were collected from the Finnish National Cancer Registry and the medical records of patients diagnosed during 1990-2009. Fifty-seven patients with surgically treated ESFTs were included, 22 with an axial and 35 with a peripheral primary tumours. The surgical treatment, its complications, survival and prognostic factors were analysed.

RESULTS

Fifty-four patients underwent surgery with a curative intent and three underwent de-bulking operations. Bone reconstruction was performed in six patients with an axial and 15 with a peripheral tumour. Positive resection margins were associated with a worse five-year local relapse-free survival (33% vs. 84% for those with resection margins free of tumour cells, p = 0.003). The five-year sarcoma-specific survival was affected only by an axial location of the primary (61% vs. 89% for those with a peripheral tumour, p = 0.031). The late complications were mainly associated with bone reconstruction and more frequent among patients with a peripheral compared to an axial tumour (p = 0.031).

CONCLUSIONS

In the treatment of ESFTs, achieving adequate resection margins is crucial to avoid local relapses. Surgical complications are common particularly with bone reconstruction.

Microvascular reconstruction after resection of soft tissue sarcoma of the leg

Background

Limb-sparing surgery and satisfactory functional outcome is the goal of extremity soft tissue sarcoma (STS) surgery. Tissue defects after tumour excision are often extensive, and microvascular reconstruction is frequently required.

Methods

Seventy-three patients with STS of the leg requiring microvascular reconstruction were treated between 1985 and 2006. Radiotherapy was delivered if the microscopic surgical margin was less than 2·5 cm.

Results

Mean follow-up was 65·9 months. Seventy-five free flaps were performed, with a success rate of 95 per cent. One patient died within a month of surgery. Five-year local recurrence-free survival was 82 per cent, metastasis-free survival 59 per cent, disease-free survival 56 per cent and disease-specific overall survival 70 per cent. Fifty-five (75 per cent) of the 73 patients were able to walk normally or had only minor walking impairment.

Conclusion

Without microvascular reconstruction, amputation would have been necessary in most patients. Microvascular reconstruction is safe and reliable in lower extremity STS reconstruction.

Impact of the smallest surgical margin on local control in soft tissue sarcoma

BACKGROUND

The aim was to review a single-institution experience of a prospective treatment protocol for soft tissue sarcoma of the extremity and trunk wall, with particular focus on the smallest surgical margin leading to local control.

METHODS

The study included 270 patients who had surgery for soft tissue sarcoma at Helsinki University Central Hospital between 1987 and 1997. Resection margins were measured prospectively from tumour specimens. Radiotherapy was administered if the smallest margin measured less than 2.5 cm, irrespective of tumour grade.

RESULTS

With a median follow-up of 6.6 years, the 5-year local control rate was 76.4 per cent. On multivariable analysis, the smallest surgical margin around the sarcoma (after radiotherapy) was prognostic for local control. A margin of at least 2.5 cm was associated with a local recurrence-free rate of 89.2 per cent at 5 years. Tumour size, depth or grade and patient's age had no independent prognostic effect on local control.

CONCLUSION

Surgical margin had independent prognostic value for local control. A surgical margin of 2-3 cm provided reasonable local control of soft tissue sarcoma, even without radiotherapy. Radiotherapy is recommended for smaller margins, irrespective of tumour grade.

Impact of the smallest surgical margin on local recurrence in soft tissue sarcoma treated with surgery with or without radiotherapy: First ten year results of a prospective treatment protocol at Helsinki University Central Hospital

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Background: A single-institution experience using a prospective treatment protocol for soft tissue sarcoma (STS) of the extremity and trunk wall was reviewed. Special interest of smallest surgical margin on local control was taken. Methods: Between 1987 and 1997 361 patients with STS were treated by the STS Group at Helsinki University Central Hospital. Patients with borderline malignancies or metastatic disease were excluded leaving 270 patients to the present study. All patients included underwent surgery. Postoperative radiotherapy was administered if the smallest surgical margin was less than 2.5 cm when there was no natural barrier, irrespective of tumor grade. Results: With a median follow-up of 6.6 years, the 5-year local control for the whole study population was 76 %. On multivariate analysis, the smallest surgical margin in centimeters, adequacy of treatment according to protocol and postirradiation sarcoma were prognostic for local control. A margin of at least 2,5 cm yielded recurrence-free rate of 89 % at five years. Conclusions: Our findings show that size, depth and grade of the tumor, and patient`s age at diagnosis do not have independent prognostic effect on local control, nor has recurrent disease at referral. Instead, surgical margin in centimeters and adequacy of treatment according to protocol had independent prognostic value for local control. This is encouraging since these factors can be affected by aggressive local treatment. Soft tissue sarcomas should be referred to a specialized multimodality treatment group before biopsy or any surgery. A surgical margin of 2–3 cm yield a reasonable local control in STS even without radiotherapy.

No significant financial relationships to disclose.

Prognostic impact of chromosomal aberrations in Ewing tumours

Although greater than 50% of Ewing tumours contain non-random cytogenetic aberrations in addition to the pathognomonic 22q12 rearrangements, little is known about their prognostic significance. To address this question, tumour samples from 134 Ewing tumour patients were analysed using a combination of classical cytogenetics, comparative genomic and fluorescence in situ hybridisation. The evaluation of the compiled data revealed that gain of chromosome 8 occurred in 52% of Ewing tumours but was not a predictive factor for outcome. Gain of 1q was associated with adverse overall survival and event-free survival in all patients, irrespective of whether the tumour was localised or disseminated (overall survival: P=0.002 and P=0.029; event-free survival: P=0.018 and P=0.010). Loss of 16q was a significant predictive factor for adverse overall survival in all patients (P=0.008) and was associated with disseminated disease at diagnosis (P=0.039). Gain of chromosome 12 was associated with adverse event-free survival (P=0.009) in patients with localised disease. These results indicate that in addition to a 22q12 rearrangement confirmation in Ewing tumours it is important to assess the copy number of 1q and 16q to identify patients with a higher probability of adverse outcome.

Comparative genomic hybridization of postirradiation sarcomas

BACKGROUND

Radiotherapy is a known risk factor for sarcoma development. Postirradiation sarcomas arise within the radiation field after a latency period of several years and usually are highly malignant. Very little is yet known about their genetic changes.

METHODS

Twenty-seven postirradiation sarcomas were analyzed by comparative genomic hybridization, which allows genome-wide screening of DNA sequence copy number changes.

RESULTS

Copy-number aberrations were detected in 20 (74%) tumors. The mean number of aberrations per tumor was 5.3 with gains outnumbering losses. The most frequent gains affected the minimal common regions of 7q11.2-q21 and 7q22 in 30% and 7p15-pter in 26%. Gain of 8q23-qter was detected in 22%. The most frequent losses affected 11q23-qter and 13q22-q32 in 22%. In osteosarcomas, the most frequent aberration was loss of 1p21-p31, in malignant fibrous histiocytomas (MFH) gain of 7cen-q22, and in fibrosarcomas gain of 7q22. The findings in postirradiation osteosarcomas and MFHs were compared with findings in sporadic osteosarcomas and MFHs, reported previously by the authors. In sporadic osteosarcomas, gains outnumbered losses, but, in postirradiation osteosarcomas, losses were more frequent than gains. Loss at 1p was rare in sporadic osteosarcoma (3%) but frequent (57%) in postirradiation osteosarcomas. Gains at 7q were frequent both in postirradiation and sporadic MFH.

CONCLUSIONS

According to previous studies on different types of sporadic sarcomas, gains at 7q or 8q are associated with poor prognosis or large tumor size. Thus, the frequent gains at 7q and 8q might have been responsible in part for the poor prognosis of postirradiation sarcomas. Also, however, some of their clinical features, i.e., high malignancy grade, late diagnosis, and central location, are associated with a poor prognosis.

Comparative genomic hybridization of postirradiation sarcomas

BACKGROUND

Radiotherapy is a known risk factor for sarcoma development. Postirradiation sarcomas arise within the radiation field after a latency period of several years and usually are highly malignant. Very little is yet known about their genetic changes.

METHODS

Twenty-seven postirradiation sarcomas were analyzed by comparative genomic hybridization, which allows genome-wide screening of DNA sequence copy number changes.

RESULTS

Copy-number aberrations were detected in 20 (74%) tumors. The mean number of aberrations per tumor was 5.3 with gains outnumbering losses. The most frequent gains affected the minimal common regions of 7q11.2-q21 and 7q22 in 30% and 7p15-pter in 26%. Gain of 8q23-qter was detected in 22%. The most frequent losses affected 11q23-qter and 13q22-q32 in 22%. In osteosarcomas, the most frequent aberration was loss of 1p21-p31, in malignant fibrous histiocytomas (MFH) gain of 7cen-q22, and in fibrosarcomas gain of 7q22. The findings in postirradiation osteosarcomas and MFHs were compared with findings in sporadic osteosarcomas and MFHs, reported previously by the authors. In sporadic osteosarcomas, gains outnumbered losses, but, in postirradiation osteosarcomas, losses were more frequent than gains. Loss at 1p was rare in sporadic osteosarcoma (3%) but frequent (57%) in postirradiation osteosarcomas. Gains at 7q were frequent both in postirradiation and sporadic MFH.

CONCLUSIONS

According to previous studies on different types of sporadic sarcomas, gains at 7q or 8q are associated with poor prognosis or large tumor size. Thus, the frequent gains at 7q and 8q might have been responsible in part for the poor prognosis of postirradiation sarcomas. Also, however, some of their clinical features, i.e., high malignancy grade, late diagnosis, and central location, are associated with a poor prognosis.

Primary soft tissue sarcoma and its local recurrence: genetic changes studied by comparative genomic hybridization

The aims of this study were to compare genetic aberrations in primary soft-tissue sarcomas and their local recurrences and to evaluate the genetic changes occurring during tumor progression. A primary soft-tissue sarcoma and its subsequent local recurrence were analyzed in 20 tumor pairs by comparative genomic hybridization. The samples were obtained before application of radio- or chemotherapy. Copy number aberrations were detected in 50% of the primary tumors and in 70% of the local recurrences. In primary tumors, the mean number of changes was 2.45 (range, 0 to 11) whereas in local recurrences, it was 5.05 (range, 0 to 17). The mean increase of changes from primary tumor to local recurrence was 2.6 per tumor pair (P =.02). Gains predominated over losses in both primary tumors and their local recurrences. The number of high-level amplifications was twofold in local recurrences. The most frequent gain affected 5p14-p15.1 (10% of primary tumors, 25% of local recurrences) and the most frequent loss, 9p (9p21-pter in 5% of primary tumors; 9p22-pter in 30% of local recurrences). In conclusion, our results show an increase in the number of genetic changes in local recurrences, due to tumor progression. Loss at 9p and gains at 5p and 20q were more frequent in local recurrences, and high-level amplification of 18p11.3 was not detected in any of the primary tumors. Although all these alterations were not specific to local recurrences, they may represent changes important during tumor progression.

Simultaneous paired analysis of numerical chromosomal aberrations and DNA content in osteosarcoma

Relatively little is known about the biologic relevance of numerical chromosomal changes in relation to DNA content in osteosarcoma. In this study, by using a series of human osteosarcoma cell lines, we standardized a method for the assessment, on the same nuclei specimen, of both specific chromosome copy numbers by fluorescence in situ hybridization (FISH) and the DNA content by static cytofluorometry or image cytometry. On the same cell lines, we also evaluated the DNA content by using flow cytometry and the chromosome number distribution by metaphase analysis. Comparison between these different methods showed that DNA ploidy level as determined by FISH or metaphase analysis is frequently lower than the ploidy pattern as defined by cytometric methods. By using comparative genomic hybridization, we were able to demonstrate that these discrepancies were due to the presence of several unbalanced chromosome aberrations, specifically gains and high-level amplifications, which affect the total DNA content with less effect on the total chromosome number. Thus, evaluation of DNA ploidy in osteosarcoma cells is needed for a correct interpretation of FISH or cytogenetic data concerning numerical chromosomal changes. Evaluation of tumor ploidy in a series of clinical samples demonstrated that in high-grade osteosarcoma, flow cytometry sometimes may give false results because of the presence of high proportions of contaminating, nonneoplastic cells that cannot be excluded from the flow cytometric assessment but that do not interfere with the evaluation of DNA ploidy by static cytofluorometry or image cytometry, in which only tumor cells are selected for the analysis. The possibility of using this method to evaluate, on the same nuclei sample, both specific chromosomal aberrations and DNA ploidy may allow a better determination of numerical chromosomal changes that may be relevant for the biologic behavior of osteosarcoma.

Novel findings in gene expression detected in human osteosarcoma by cDNA microarray

cDNA microarray analysis was used to screen for gene expression alterations in human osteosarcoma cell lines. The analysis using three cell lines revealed changes in the expression of several genes in comparison with normal human osteoblasts. Among the 5,184 sequences that were analyzed, 35 showed aberrant expression in all the cell lines. Eight of these showed overexpression and 27 underexpression compared to their expression levels in osteoblasts. The most highly up-regulated genes included heat shock protein 90beta and polyadenylate-binding protein-like 1. Commonly down-regulated genes included fibronectin 1 and thrombospondin 1. RT-PCR was used to verify these changes in the cell lines and in three primary osteosarcoma samples. This study shows that (1) gene expression pattern in osteosarcoma cell lines differs considerably from normal osteoblasts, (2) osteosarcoma cell lines can be used as a model system to detect novel gene expression alterations present in primary tumors, (3) the overexpression of heat shock protein 90beta and polyadenylate-binding protein-like 1, and (4) the down-regulation of fibronectin 1 and thrombospondin 1 may play a role in the development and/or progression of osteosarcoma. This study indicates that microarray-based expression surveys may be used to establish the molecular fingerprint of osteosarcoma, however, larger cDNA chips and more tumor specimens are required to define the clinically relevant gene expression patterns.

Clinical significance of genetic imbalances revealed by comparative genomic hybridization in chondrosarcomas

DNA copy number changes were studied by comparative genomic hybridization (CGH) in 50 chondrosarcoma samples from 45 patients. Mean number of genetic aberrations in primary tumors was 4.8 +/- 1.8. The most frequently gained regions were 20q12-qter (37%), 20q (32%), 8q24.1-qter (27%), 20p (24%), and 14q24-qter (24%). Losses were 5.5 times less frequent than gains and observed mainly at Xcen-q21, 6cen-q22, and 18cen-q11.2 (11% each). Recurrent and metastatic tumors showed a mean of 4.0 +/- 2.2 aberrations per sample. The most frequently gained regions were chromosome 7 (4 cases), 5q14-q32 (4 cases), 6p (3 cases), and 12q (3 cases). Losses of DNA sequences were 3.4 times less frequent than gains. Histological tumor grade was significantly associated with metastasis-free survival (P = .002) and overall survival (P = .003), being the strongest prognostic factor tested. A statistically significant correlation was found between gain at 8q24.1-qter and shorter overall survival (P = .01) but not with local recurrence or metastasis-free survival. Gain at 14q24-qter was associated with a trend to shorter overall survival (P = .05) but neither with an increased risk for local recurrence nor with metastasis-free survival. In a multivariate analysis, only the tumor grade associated with overall survival (P = .02). In a multivariate analysis together with the tumor grade, gain at 8q24.1-qter did not retain its significance (P = .44), indicating that this imbalance is not an independent prognostic factor.

Clinical correlations of genetic changes by comparative genomic hybridization in Ewing sarcoma and related tumors

Our previous comparative genomic hybridization (CGH) study of Ewing sarcoma and related tumors showed that DNA sequence copy number increases of 1q21-q22 and of chromosomes 8 and 12 were associated with trends toward poor survival (Armengol et al., Br J Cancer 1997, 75, 1403-1409). These trends were not statistically significant. In the present study, we analyzed 28 primary Ewing sarcomas and related tumors by CGH to study whether these (or other) changes have prognostic value in these tumors. Twenty-one tumors (75%) had changes with a mean of 1.9 changes per tumor. The most frequent aberration was gain of chromosome 8 in 10 tumors (36%). Five tumors (18%) had copy number increases at 1q21-22 and 5 had gain of 7q. Copy number increase of 6p21.1-pter, gain of chromosome 12, and loss of 16q were seen in 11%. Copy number increases of 1q21-q22 and of chromosomes 8 and 12 were associated with trends toward worse outcome, but the differences did not reach statistical significance. A novel finding is the association of copy number increase at 6p with worse distant disease-free (P = 0.04) and overall survival (P = 0.004). To confirm this finding and to see whether copy number increases of 1q21-q22 and of chromosomes 8 and 12 have definite prognostic value, a larger number of cases needs to be studied.

DNA copy number losses in human neoplasms

This review summarizes reports of recurrent DNA sequence copy number losses in human neoplasms detected by comparative genomic hybridization. Recurrent losses that affect each of the chromosome arms in 73 tumor types are tabulated from 169 reports. The tables are available online at http://www.amjpathol.org and http://www. helsinki.fi/ approximately lglvwww/CMG.html. The genes relevant to the lost regions are discussed for each of the chromosomes. The review is supplemented also by a list of known and putative tumor suppressor genes and DNA repair genes (see Table 1, online). Losses are found in all chromosome arms, but they seem to be relatively rare at 1q, 2p, 3q, 5p, 6p, 7p, 7q, 8q, 12p, and 20q. Losses and their minimal common overlapping areas that were present in a great proportion of the 73 tumor entities reported in Table 2 (see online) are (in descending order of frequency): 9p23-p24 (48%), 13q21 (47%), 6q16 (44%), 6q26-q27 (44%), 8p23 (37%), 18q22-q23 (37%), 17p12-p13 (34%), 1p36.1 (34%), 11q23 (33%), 1p22 (32%), 4q32-qter (31%), 14q22-q23 (25%), 10q23 (25%), 10q25-qter (25%),15q21 (23%), 16q22 (23%), 5q21 (23%), 3p12-p14 (22%), 22q12 (22%), Xp21 (21%), Xq21 (21%), and 10p12 (20%). The frequency of losses at chromosomes 7 and 20 was less than 10% in all tumors. The chromosomal regions in which the most frequent losses are found implicate locations of essential tumor suppressor genes and DNA repair genes that may be involved in the pathogenesis of several tumor types.

Comparison of genetic changes in primary sarcomas and their pulmonary metastases

The aims of the present study were to compare genetic aberrations in primary sarcomas and their pulmonary metastases and to explore the pathways associated with disease spreading. The primary tumor and its subsequent pulmonary metastasis of 22 patients were analyzed by comparative genomic hybridization. All samples were obtained before the initiation of chemo- or radiotherapy. The mean total number of aberrations per tumor was 7.6 (range, 0-17) in primary tumors and 7. 5 (range, 0-19) in metastases. The mean numbers of high-level amplifications per tumor were similar (0.32 in primary tumors and 0. 36 in metastases). The frequencies of the most common aberrations were relatively similar in primary tumors and metastases: the most frequent gain affected 1q (minimal common regions 1q21-q23 in 36% of primary tumors and 1q21 in 45% of metastases). The most frequent losses were detected at 9p (9p22-pter in 32% of primary tumors and 9p21-pter in 32% of metastases), 10p (10p11.2-p12 in 41% of primary tumors and 10p11.2-pter in 32% of metastases), 11q (11q23-qter in 36% of primary tumors and 32% of metastases), and 13q (13q14-q21 in 45% of primary tumors and 50% of metastases). No aberrations specific to metastases were detected. An increase in the total number of changes during progression was a predominant feature in a majority of these paired samples. Also, the number of differences in the genetic profile outnumbered common changes in a majority of the samples. However, despite the heterogeneous and numerous changes, all pairs with aberrations in both specimens had some shared alterations in both samples. Genes Chromosomes Cancer 25:323-331, 1999.

Characterization of the 17p amplicon in human sarcomas: microsatellite marker analysis

The structure of the 17p amplicon from 9 human sarcoma specimens evaluated by comparative genomic hybridization (CGH) has been studied by analyzing 28 microsatellite markers by PCR. Eleven sarcoma specimens showing no DNA copy number increases at 17p by CGH were analyzed as control samples. Five specimens were analyzed by Southern blotting using probes that have previously shown amplification at the 17p12 region in astrocytoma and high-grade osteosarcoma samples. Microsatellite marker analyses revealed that all samples but 1 showing copy number increases at 17p by CGH displayed allelic imbalance that confirmed the CGH findings. Seven of these 9 cases displayed gain in copy number by microsatellite marker analysis. Four cases displaying gain in copy number were associated with loss of heterozygosity at other loci. Southern blot analysis showed amplification in 3 cases, all of them had shown copy number increases by CGH and microsatellite marker analysis, except one case, which was not included in the microsatellite marker analysis. Our results reveal the complexity of the 17p amplicon in sarcomas, suggesting that multiple target genes are involved in tumorigenesis.

DNA sequence copy number increase at 8q: a potential new prognostic marker in high-grade osteosarcoma

Histologic response to chemotherapy is currently the best prognostic parameter in high-grade osteosarcoma but it can be evaluated only after several weeks of chemotherapy. Thus a prognostic parameter known at the time of diagnosis would be of great clinical benefit. In the present study, we present the results of 31 primary high-grade osteosarcomas analyzed by comparative genomic hybridization (CGH). CGH allows for genome-wide screening of a tumor by detecting alterations in DNA sequence copy number. The most frequent aberrations were copy number increases at 1q21 in 58% of the tumors and at 8q (8q21.3-q22 in 52% and 8cen-q13 in 45%), followed by copy number increases at 14q24-qter (35%) and Xp11.2-p21 (35%). The most common losses were detected at 6q16 (32%) and 6q21-q22 (32%). Patients with a copy number increase at 8q21.3-q22 and/or at 8cen-q13 had a statistically significant poor distant disease-free survival (p = 0.003) and showed a trend toward short overall survival (p = 0.04). Patients with a copy number increase at 1q21 showed a trend toward short overall survival (p = 0.04). Thus, specific genetic aberrations detected at the time of the diagnosis could be used in prognostic evaluation of high-grade osteosarcoma.

LKB1 somatic mutations in sporadic tumors

Germline mutations of LKB1/Peutz-Jeghers syndrome gene predispose carriers to hamartomatous polyposis of the gastrointestinal tract as well as to cancer of different organ systems. Although Peutz-Jeghers syndrome patients frequently present with neoplasms of the colon, stomach, small intestine, pancreas, breast, ovaries, and cervix, somatic mutations appear to be rare in the sporadic tumor types thus far studied (colorectal, gastric, testicular, and breast cancers). To evaluate whether somatic mutations of LKB1 contribute to the tumorigenesis of yet unstudied tumor types, we screened 14 cell lines and 129 tumor specimens from different cancers for a genetic defect in LKB1. Six melanoma and eight myeloma cell lines were scrutinized for LKB1 somatic mutations by genomic sequencing. No changes were found in the coding LKB1 sequence and exon/intron boundaries. Next, we analyzed 12 pancreatic, 8 gastric, 12 ovarian granulosa cell, 26 cervical, 28 lung, 24 soft tissue, and 19 renal tumors by single-strand conformational polymorphism analysis. Three changes in LKB1 coding nucleotide sequence were identified. One base pair deletion at A957 and G958 substitution by T occurred in a cervical adenocarcinoma sample, resulting in a frameshift and premature stop codon at position 335. Substitution of A581 by T occurred in a lung adenocarcinoma sample, resulting in the change of aspartic acid at position 194 to valine. A loss of another allele was detected in this sample. One silent change, C1257T, was found in a pancreatic carcinoma sample. The changes were not present in the matched normal tissue DNA samples. Our results suggest that mutational inactivation of LKB1 is a rare event in most sporadic tumor types.

Genetic imbalances in 67 synovial sarcomas evaluated by comparative genomic hybridization

We used comparative genomic hybridization (CGH) to evaluate DNA sequence copy number changes in 67 synovial sarcomas of both monophasic and biphasic histological subtypes. Changes (mean among aberrant cases: 4.7 aberrations/tumor; range: 1-17), affecting most often entire chromosomes or chromosome arms, were detected in 37 sarcomas (55%). Gains and losses were distributed equally, but different chromosomes were affected with variable frequencies. The most frequent aberrations, each detected in 9-11 of 67 tumors, were gain of 8q and gain at 12q (12q14-15 and 12q23-qter), loss of 13q21-31, and loss of 3p. Other frequent changes (in 7 or 8 cases) included gains at 2p, 1q24-31, and 17q22-qter, and losses at 3cen-q23 and 10q21. High-level amplifications were seen in 7 cases. A total of 16 regions were detected. Two of them, 8p12-qter and 21q21-qter, seen in 4 and 2 tumors, respectively, were recurrent. No aberrations specific to histological subtype were identified. However, genetic changes in the monophasic tumors were more complex and numerous (mean among aberrant cases: 5.3 aberrations/tumor; range: 1-17) than in the biphasic tumors (mean: 2.5 aberrations/tumor; range: 1-5), and high-level amplifications occurred more frequently. All but 1 of the sarcomas showing high-level amplification were of the monophasic subtype. These findings may reflect differences in the pathogenesis and biological behavior of both histological subtypes of synovial sarcoma.

DNA copy number amplifications in human neoplasms: review of comparative genomic hybridization studies

This review summarizes reports of recurrent DNA sequence copy number amplifications in human neoplasms detected by comparative genomic hybridization. Some of the chromosomal areas with recurrent DNA copy number amplifications (amplicons) of 1p22-p31, 1p32-p36, 1q, 2p13-p16, 2p23-p25, 2q31-q33, 3q, 5p, 6p12-pter, 7p12-p13, 7q11.2, 7q21-q22, 8p11-p12, 8q, 11q13-q14, 12p, 12q13-q21, 13q14, 13q22-qter, 14q13-q21, 15q24-qter, 17p11.2-p12, 17q12-q21, 17q22-qter, 18q, 19p13.2-pter, 19cen-q13.3, 20p11.2-p12, 20q, Xp11.2-p21, and Xp11-q13 and genes therein are presented in more detail. The paper with more than 150 references and two tables can be accessed from our web site http://www.helsinki.fi/lglvwww/CMG.html. The data will be updated biannually until the year 2001.

Comparative genomic hybridization of low-grade central osteosarcoma

Very little is known concerning the cytogenetic and molecular genetic changes of low-grade central osteosarcoma, a rare form of osteosarcoma. In the present study, we used comparative genomic hybridization (CGH) to screen for DNA sequence copy number aberrations in 10 samples from 6 patients: 7 typical low-grade central osteosarcomas, one low-grade (Grade II) central osteosarcoma, and two high-grade (III and IV) local recurrences of a low-grade central osteosarcoma Nine samples had aberrations. Six typical low-grade central osteosarcoma samples had a single DNA sequence copy number change per tumor. Three samples from more advanced tumors (a Grade II low-grade central osteosarcoma and local recurrences of Grade III and IV) had a mean of five changes per tumor. Recurrent changes affected these minimal common regions: +12q13-q14 (three tumors), +12p (two tumors), and +6p21.1-p21.3 (two tumors). Nine samples were analyzed for CDK4 and MDM2 expression and SAS amplification. One sample with a gain of chromosome 12 had a very strong expression of MDM2, strong expression of CDK4, and amplification of SAS. One sample with a gain of 12q13-q14 had strong expression of CDK4 and MDM2. Strong expression of CDK4 was found in two additional tumors; one had a gain of 12q13-q21, and the other had no changes in chromosome 12 by CGH. No alterations were detected in the CDK4, MDM2, and SAS panel in three other samples with no changes in chromosome 12 by CGH. In conclusion, the low number of DNA sequence copy number alterations reflects the relatively low malignancy of low-grade central osteosarcoma. This simplicity differs from the complex aberrations seen in conventional high-grade osteosarcomas.

Overrepresentation of 1q21-23 and 12q13-21 in lipoma-like liposarcomas but not in benign lipomas: a comparative genomic hybridization study

Twenty lipomatous tumors, including eight lipoma-like liposarcomas and 12 benign lipomas, were analyzed using comparative genomic hybridization (CGH). DNA sequence copy number changes detected in five lipoma-like liposarcomas (mean, 1.1 aberrations/tumor; range, 0-2) consisted of gains of 12q13-21 (five tumors) and 1q21-23 (four tumors). Two of the tumors showed high-level amplification at 12q14-21 and one tumor at 1q21-22. No copy number changes were found in lipomas. Overrepresentation of 1q and 12q sequences was a recurrent finding in lipoma-like liposarcomas but not in lipomas. Thus, CGH may help in the differential diagnosis of low-grade or borderline adipose neoplasms.

Comparative genomic hybridization of malignant fibrous histiocytoma reveals a novel prognostic marker

DNA sequence copy number changes were studied by comparative genomic hybridization (CGH) along all chromosomes in 58 samples of malignant fibrous histiocytoma (MFH). The material consisted of 43 primary tumors (9 of myxoid and 34 of storiform-pleomorphic subtype), 13 local recurrences (2 myxoid and 11 storiform-pleomorphic), and 2 metastases (1 myxoid and 1 storiform-pleomorphic). Genetic aberrations, with a mean of 5.5 changes per sample (range, 0 to 22), were detected in 47 of 58 samples (81%). The minimal common regions of the most frequent gains were 1p31 (33%), 9q31 (29%), 5p14-pter (26%), 7q32 (24%), and 7p15-pter (22%). High-level amplifications were detected in 16 of the 58 samples (28%). High-level amplification of 13q31-qter was seen in four tumors (7%); other high-level amplifications were more sporadic. Losses of DNA sequences were less frequent than gains. The minimal common regions of the most common losses were 13q21 (21%) and 13q22 (21%). Statistically significant correlation was found between gain of 7q32 and the rates of worse metastasis-free survival (P = 0.01) and overall survival (P = 0.004). The gain of 7q32 retained its prognostic significance also in a multivariate analysis with tumor size and grade. Gain of 1p31 was associated with a trend to decreased overall survival. Gains of 5p14-pter and 9q31 and losses of 13q21 and/or 13q22 did not have any prognostic value; neither did the total number of aberrations, total number of gains, or total number of losses per sample.

No DNA copy number changes in osteochondromas: a comparative genomic hybridization study

Cytogenetic changes in osteochondroma samples were studied by comparative genomic hybridization and by chromosome banding. No DNA copy number changes (15 patients) or chromosomal aberrations (9 patients) were observed in any of the patients.

Gains, losses, and amplifications of DNA sequences evaluated by comparative genomic hybridization in chondrosarcomas

Comparative genomic hybridization was used to search for previously unknown gains and losses of DNA sequences along all chromosome arms in 29 chondrosarcoma specimens obtained from 23 patients. Extensive genetic aberrations, with a mean of 6 changes per tumor (range, 1 to 24), were detected in 21 of the 29 samples analyzed (72%). The majority of these changes were gains of whole chromosomes or whole chromosome arms. Gains of DNA sequence copy number were most frequent at 20q (38%), 17p (38%), 20p (31%), 1cen-q24 (28%), and 14q23-qter (28%). High-level amplifications of small chromosome regions were sporadic, detected in only 17% of the samples. The only recurrent high-level amplification, seen in two tumors (7%), affected the minimal common region 12cen-q15. Other amplifications, each encountered only once, involved 1p33-p35, 2p23-pter, 4p, 6p22-pter, 18q12-q22, 19p13.2, 19q13.2, and 20q13.1. Losses of DNA sequences were rare and were most commonly observed at 6cen-q22 (17%) and 9p (17%).

Microsatellite markers as tools for characterization of DNA amplifications evaluated by comparative genomic hybridization

To test the applicability of microsatellite markers in the study of DNA amplifications evaluated by comparative genomic hybridization, we analyzed 55 highly polymorphic microsatellite marker loci from six liposarcoma tumors (seven specimens) and from one atypical lipoma with a gain or high-level amplification at 12q13-22. Twelve-trisomic neoplastic cells from a patient with B-cell chronic lymphocytic leukemia were used as a positive control, in which 74% of informative loci showed allelic imbalance. In every tumor specimen microsatellite marker loci analysis showed allelic imbalance. The amplicons were discontinuous, indicating the presence of separate amplicons in the 12q13-22 region. Not only gains but also losses as well as concomitant gains and losses of alleles were observed. The use of microsatellite markers has several advantages: gene loci as well as flanking DNA loci can be analyzed, it is fast and lends itself to automation, and allows a large number of marker loci to be analyzed simultaneously.

Complexity of 12q13-22 amplicon in liposarcoma: microsatellite repeat analysis

The 12q13-22 amplicon from four liposacroma specimens evaluated by comparative genomic hybridization was studied analyzing 55 microsatellite markers by PCR. All four specimens were informative in at least 34 loci; an amplification or allelic imbalance was identified with four to 17 markers. The amplicons were discontinuous; there were non-amplified marker loci between the amplified marker loci. These findings indicate the presence of separate amplicons in the 12q13-22 region. Evidence of the concomitant gain of one allele and loss of the other allele was found with several markers in one tumor and with one marker in two tumor specimens. Southern blotting showed amplification of CDK4 and MDM2 in all four specimens.

Recurrent gains of 1q, 8 and 12 in the Ewing family of tumours by comparative genomic hybridization

Comparative genomic hybridization (CGH) was used to detect copy number changes of DNA sequences in the Ewing family of tumours (ET). We analysed 20 samples from 17 patients. Fifteen tumours (75%) showed copy number changes. Gains of DNA sequences were much more frequent than losses, the majority of the gains affecting whole chromosomes or whole chromosome arms. Recurrent findings included copy number increases for chromosomes 8 (seven out of 20 samples; 35%), 1q (five samples; 25%) and 12 (five samples; 25%). The minimal common regions of these gains were the whole chromosomes 8 and 12, and 1q21-22. High-level amplifications affected 8q13-24, 1q and 1q21-22, each once. Southern blot analysis of the specimen with high-level amplification at 1q21-22 showed an amplification of FLG and SPRR3, both mapped to this region. All cases with a gain of chromosome 12 simultaneously showed a gain of chromosome 8. Comparison of CGH findings with cytogenetic analysis of the same tumours and previous cytogenetic reports of ET showed, in general, concordant results. In conclusion, our findings confirm that secondary changes, which may have prognostic significance in ET, are trisomy 8, trisomy 12 and a gain of DNA sequences in 1q.

Comparison of cytogenetics, interphase cytogenetics, and DNA flow cytometry in bone tumors

Twenty-three samples of benign and malignant bone tumors were studied with cytogenetic analysis, interphase cytogenetics (IC) using in situ hybridization with (peri)centromeric probes for chromosomes 1, 7, and/or 8, and DNA flow cytometry (FCM). Our aim was to compare these methods in the detection of numerical chromosome aberrations (NCA) and aneuploidy. IC detected aneuploidy in 91%, FCM in 73%, and cytogenetics in 27% of the malignant tumors. In benign tumors IC detected aneuploid by in 4(33%), FCM in 2(17%), and cytogenetic analysis in 1. All of the benign tumors aneuploid by IC, two of which were also aneuploid by FCM, were histologically potentially aggressive. The clonal aberrations detected with cytogenetics usually agreed with the IC and FCM findings. All malignant tumors which had a normal karyotype were aneuploid either by IC or FCM or by both. In conclusion, IC was the most sensitive method in the detection of NCA and aneuploidy even though it was usually performed with only two (peri)centromeric probes. Aneuploidy was detected by cytogenetic analysis alone in 4 samples (17%), by cytogenetic analysis and/or FCM in 11 samples (48%), and by cytogenetic analysis, FCM, and/or IC in 16 samples (70%). Thus, the combined use of all three methods increased the sensitivity of aneuploidy detection.

No evidence of microsatellite instability in bone tumours

Microsatellite instability has recently been reported in sporadic and familial colorectal tumours and can be due to defects in DNA mismatch repair genes. Such instability has subsequently been detected in several other types of sporadic tumours. We studied 29 specimens of bone tumours with different histopathological diagnoses and found no evidence of microsatellite instability. Our results suggest that mismatch repair defects are unlikely to play a significant part in the tumorigenesis of bone neoplasms. Loss of heterozygosity with at least one marker was detected in 11, i.e. in 38% of the tumour samples, most frequently with markers D2S136 at 2p (eight of 28 informative specimens, 29%) and D11S904 at 11p (four of 21 informative specimens, 19%).

Growth rate of lung metastases and S-phase fraction as determined by flow cytometry from the primary tumour in 25 patients with bone or soft-tissue sarcomas

A significant correlation (r = -0.48) was found between the logarithm of the S-phase fraction of the primary tumour (SPF) and the logarithm of the doubling time of lung metastases (T2). The estimated median cell loss factor was 88% (range 35-99%).

Ring chromosomes in parosteal osteosarcoma contain sequences from 12q13-15: a combined cytogenetic and comparative genomic hybridization study

Seven parosteal osteosarcoma (POS) samples, six of which were cytogenetically characterized, were studied by using comparative genomic hybridization (CGH). All samples showed DNA sequence copy number changes (mean, six aberrations/tumor; range, 1-13); gains were more frequent than losses. Gain of 12q13-15 sequences was found in every tumor and correlated with the presence of ring chromosomes. High-level amplification, which was detected in four tumors, was seen only in chromosome 12, with 12q13-14 as the minimal common region. By using chromosome painting, one of the rings of one case was shown to be composed entirely of chromosome 12 material. Together with previous data, our findings show that gain of 12q13-15 sequences is a characteristic feature of POS and that these sequences are contained within the ring chromosomes.

Gains and losses of DNA sequences in liposarcomas evaluated by comparative genomic hybridization

Comparative genomic hybridization (CGH) was used to detect and map the regions of gain, high-level amplification, and loss of DNA sequences in 14 liposarcomas. Thirteen tumors showed DNA sequence copy number changes of one or more genomic regions (mean, six aberrations/tumor; range, 0-17). These aberrations were observed in almost every chromosome but some chromosomal regions were affected more often than others. DNA sequence gains were more frequent than losses. The most common gain was seen at 12q14-21 (50% of tumors). Other frequent gains (29%) were of 1q21-24, 8cen-q21.2, 19q, and 20q. High-level amplification was observed in six (43%) tumors and included as minimal common segments bands 12q15, 1q22, and 1q24. In five (36%) tumors, sequences at 1q21-24 and 1q32 were found to be gained simultaneously with 12q14-21, which means that in 71% of the tumors with gain at 12q, an increase of DNA sequence copy number at 1q was also observed. The most common losses of DNA sequences (21%) occurred from regions 9p21-pter and 13q21-qter. Most of the aforementioned regions have not previously been reported to be altered in liposarcomas. The detection of a novel recurring amplicon at 1q21-24 with high-level amplification at 1q22 and frequent simultaneous DNA sequence gain at 12q14-21 (high-level amplification at 12q15) suggests that genes linked to both these regions may play a significant role in the development and progression of liposarcomas.

Cytogenetic study of extraskeletal mesenchymal chondrosarcoma. A case report

Extraskeletal mesenchymal chondrosarcoma (EMC) is a rare and highly malignant type of chondrosarcoma of soft tissue origin. We performed a cytogenetic study on a patient with EMC. Cytogenetic analysis revealed the tumor karyotype: 48-49,XX, t(4;9)(q23;q22), add(10)(q?26), +16, ?del(19)(p13), +1-2mar[cp12] / 48-50,idem, t(1;20)(q21;q13), +mar[cp6] / 46,XX [7].

A cytogenetic study of malignant fibrous histiocytoma

We report the results of cytogenetic analysis of malignant fibrous histiocytoma of soft tissue (MFH). Seven of 12 successfully cultured MFHs had complex clonal aberrations, including translocations, deletions, and unidentifiable marker chromosomes. Telomeric associations were observed in five and the double minute phenomenon in four of seven MFHs with abnormal karyotypes. In one case (a storiform-pleomorphic MFH, grade IV) with a complex polyploid karyotype, two clonal ring chromosomes were present, one interpreted as r(19)(p13q13), one unidentified. In two tumors, clonal structural rearrangements of chromosome 1 were seen: del(1)(q21) in a storiform-pleomorphic MFH, grade IV, and add (1)(q21 or q32), t(1;10)(p22;q22) in a myxoid MFH, grade I. The remaining five MFHs had normal karyotypes, but in two of them nonclonal, structural aberrations were found. The modal chromosome number in the studied MFHs varied widely, but the majority of tumors with abnormal karyotypes had polyploid chromosome complements (five of seven cases). Our results confirm many of the previous findings and indicate that double minutes (dmins) may be more frequent in MFH than previously reported.

Gains and losses of DNA sequences in osteosarcomas by comparative genomic hybridization

Our aim was to identify chromosomal regions that are likely to harbor previously unknown genes with an important role in the genesis of osteosarcoma. Comparative genomic hybridization was used to screen for losses and gains of DNA sequences along all chromosome arms in 11 tumors. Extensive genetic aberrations, with an average of 11 changes/tumor (range, 1-20), were found in 10 of the 11 specimens. High level amplifications of small chromosomal regions were detected in eight tumors. These involved the 12q12-q13 region (known to contain the SAS-MDM2 locus) and several previously unreported amplification sites such as 17p11-p12, 3q26, and Xq12. When all DNA sequence gains were evaluated, the gains at 8q and Xp were most common (45%). The most common losses of DNA sequences were seen at 2q, 6q, 8p, and 10p (36%). In conclusion, despite the very complex pattern of genetic changes in osteosarcomas, certain chromosomal regions appear to be affected more often than others. Most of these regions have not previously been reported to be implicated in osteosarcomas and may thus highlight locations of novel genes with an important role in the development and progression of these tumors.

Dedifferentiated chondrosarcoma with t(9;22)(q34;q11-12)

Translocation t(9;22)(q22-31;q11-12) is associated with the myxoid variant of chondrosarcoma. We present here a report of a patient with a dedifferentiated grade IV chondrosarcoma, which originated from the iliac bone and contained areas of grade I chondrosarcoma. There was no evidence of myxoid differentiation. The tumor had the karyotype 46,X,-X,t(9;22)(q34;q11-12), + mar[5]/52-61,x?,2-3 min,inc[9]/46,XX[2]. It is possible that the different breakpoints in the t(9;22) may reflect different histopathologic subgroups of chondrosarcoma.

Chromosome study of 249 patients examined for a bone tumor

The authors have performed cytogenetic studies of bone tumors since 1987, and this article, based on previous work, summarizes their experiences in this field. Altogether 304 samples from 249 consecutive patients examined for a possible bone tumor at the Helsinki University Central Hospital, between October 1987 and April 1992, have been analyzed. The series consisted of 86 nonneoplastic disorders, 108 benign and 78 malignant primary bone tumors, and 32 other bone malignancies. In the group of nonneoplastic disorders, one sample from an infectious lesion demonstrated a simple clonal chromosome aberration. Simple clonal aberrations were seen in six of 75 successfully cultured benign tumors. Complex clonal aberrations occurred in 21 of 54 successfully cultured malignant primary bone tumors and in eight of 21 secondary bone malignancies. The complexity of clonal aberrations correlated with the grade of malignancy as the osteosarcomas and chondrosarcomas of high grade demonstrated chaotic abnormalities. The chaotic nature of the aberrations implicates the evolution of several different clones and thus advanced malignant transformation. Six of eight successfully cultured Ewing's sarcomas demonstrated the diagnostic t(11;22)(q24;q12); this translocation was also seen in one primitive neuroectodermal tumor. Cytogenetic study provides increasing knowledge of the biology of bone tumors and is a valuable adjunct in their evaluation.

Measurement of growth rate of lung metastases in 21 patients with bone or soft-tissue sarcoma

The volume doubling time (T2) of 52 lung metastases in 21 patients was calculated from measurements done on plain chest radiographs. Follow-up times ranged from 14 to 819 days. The measurements were fairly well reproducible in the majority of patients, although considerable discrepancies in T2 estimates made by two independent observers were found in a few patients. The median doubling time was 34.9 days (estimated 95% range 3.9 to 352 days). The variation of T2:s between patients was significantly (P = 0.0001) larger than that between T2: of multiple metastases in the same patients. The growth of the metastases seemed to be well described by a simple exponential function in all patients with more than two measurements, without evidence of Gompertzian growth. There seemed to be a linear correlation between the logarithm of T2 and log-survival time from diagnosis of metastatic disease, even if only one third of the variation of survival times between patients could be explained by differences in T2. T2 was not a significant factor for survival in Cox-analysis (P = 0.10).

Cytogenetic study of 249 consecutive patients examined for a bone tumor

Chromosome analysis was performed on 304 samples of 249 consecutive patients examined for a possible bone tumor. The series consisted of 86 nonneoplastic disorders, 108 benign and 78 malignant primary bone tumors, and 32 other bone malignancies. In the group of nonneoplastic disorders, one sample from an infectious lesion demonstrated a clonal chromosome aberration, i.e., additional material in the short arm of chromosome 1. Simple clonal aberrations were noted in six of 75 successfully cultured benign tumors, e.g., a chondromyxoid fibroma with an insertion type translocation from 2p21p25 to 5q13 and 2p deletion and a nonossifying fibroma with del(4)(p14). Complex clonal aberrations were evident in 21 of 54 successfully cultured malignant primary bone tumors and eight of 21 secondary bone malignancies. The complexity of clonal aberrations correlated with the grade of malignancy as the osteosarcomas and chondrosarcomas of high-grade demonstrated chaotic abnormalities. Six Ewing's sarcomas demonstrated the t(11;22)(q24;q12); in one this was the sole abnormality, and in five additional changes were evident: der(1;16)(q10;p10) in one. Homogeneously staining elongated areas interpreted as HSR were observed in three patients, all of whom had a highly malignant tumor. The most frequent nonclonal abnormality was telomeric association, which was observed mainly in giant cell tumors.

A recurrent chondromyxoid fibroma with chromosome aberrations ins(5;2)(q13;p21p25) and 2p deletion: a case report

We report a patient with a recurrent chondromyxoid fibroma, a rare benign tumor of the bone with clonal aberrations in chromosomes 2 and 5. Karyotyping, chromosome painting, interphase cytogenetics by in situ hybridization, and DNA flow cytometry were used. The karyotype was interpreted as 46,XX,der(2)ins(5;2)(q13;p21p25),der(2)ins(5;2)(q13;p21p25), der(5)ins(5;2) (q13;p21p25).