Disruption of the TP53 locus in osteosarcoma leads to TP53 promoter gene fusions and restoration of parts of the TP53 signalling pathway

TP53 is the most frequently mutated gene in human cancer. This gene shows not only loss-of-function mutations but also recurrent missense mutations with gain-of-function activity. We have studied the primary bone malignancy osteosarcoma, which harbours one of the most rearranged genomes of all cancers. This is odd since it primarily affects children and adolescents who have not lived the long life thought necessary to accumulate massive numbers of mutations. In osteosarcoma, TP53 is often disrupted by structural variants. Here, we show through combined whole-genome and transcriptome analyses of 148 osteosarcomas that TP53 structural variants commonly result in loss of coding parts of the gene while simultaneously preserving and relocating the promoter region. The transferred TP53 promoter region is fused to genes previously implicated in cancer development. Paradoxically, these erroneously upregulated genes are significantly associated with the TP53 signalling pathway itself. This suggests that while the classical tumour suppressor activities of TP53 are lost, certain parts of the TP53 signalling pathway that are necessary for cancer cell survival and proliferation are retained. In line with this, our data suggest that transposition of the TP53 promoter is an early event that allows for a new normal state of genome-wide rearrangements in osteosarcoma. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Loss of NF2 defines a genetic subgroup of non-FOS-rearranged osteoblastoma

Osteoblastoma is a locally aggressive tumour of bone. Until recently, its underlying genetic features were largely unknown. During the past two years, reports have demonstrated that acquired structural variations affect the transcription factor FOS in a high proportion of cases. These rearrangements modify the terminal exon of the gene and are believed to stabilise both the FOS transcript and the encoded protein, resulting in high expression levels. Here, we applied in‐depth genetic analyses to a series of 29 osteoblastomas, including five classified as epithelioid osteoblastoma. We found recurrent homozygous deletions of the NF2 gene in three of the five epithelioid cases and in one conventional osteoblastoma. These events were mutually exclusive from FOS mutations. Structural variations were determined by deep whole genome sequencing and the number of FOS‐rearranged cases was less than previously reported (10/23, 43%). One conventional osteoblastoma displayed a novel mechanism of FOS upregulation; bringing the entire FOS gene under the control of the WNT5A enhancer that is itself activated by FOS. Taken together, we show that NF2 loss characterises a subgroup of osteoblastomas, distinct from FOS‐rearranged cases. Both NF2 and FOS are involved in regulating bone homeostasis, thereby providing a mechanistic link to the excessive bone growth of osteoblastoma.

[Synovial sarcoma - a rare and highly malignant, tumor with an ambiguous clinical picture at times]

A characteristic feature of soft tissue sarcomas is the absence of alarm symptoms such as pain or abnormal laboratory findings. We present two patients where the diagnostic difficulties delayed the definitive diagnosis, in one case with lethal outcome. The two patients highlight the difficulties a clinician may encounter with this particular disease. Even though synovial sarcoma represents around 0,1 % of all cancer forms, we recommend a high degree of awareness and - when in doubt - prompt contact with a Sarcoma center for consultation.

Genetic profiling of a chondroblastoma-like osteosarcoma/malignant phosphaturic mesenchymal tumor of bone reveals a homozygous deletion of CDKN2A, intragenic deletion of DMD, and a targetable FN1-FGFR1 gene fusion

Conventional osteosarcoma is the most common primary malignancy of bone. This group of neoplasms is subclassified according to specific histological features, but hitherto there has been no correlation between subtype, treatment, and prognosis. By in-depth genetic analyses of a chondroblastoma-like osteosarcoma, we detect a genetic profile that is distinct from those previously reported in benign and malignant bone tumors. The overall genomic copy number profile was less complex than that typically associated with conventional osteosarcoma, and there was no activating point mutation in any of H3F3A, H3F3B, IDH1, IDH2, BRAF, or GNAS. Instead, we found a homozygous CDKN2A deletion, a DMD microdeletion and an FN1-FGFR1 gene fusion. The latter alteration has been described in phosphaturic mesenchymal tumor. This tumor type shares some morphological features with chondroblastoma-like osteosarcoma and we cannot rule out that the present case actually represents an FN1-FGFR1 positive malignant phosphaturic mesenchymal tumor of bone without osteomalacia.

Preoperative radiotherapy of soft-tissue sarcomas: surgical and radiologic parameters associated with local control and survival

Background

Preoperative radiotherapy is often used to facilitate excision of soft-tissue sarcomas. We aimed define factors that affect local tumour control and patient survival.

Methods

A single institution registry study of 89 patients with non-metastatic soft-tissue sarcomas having preoperative radiotherapy between 1994 and 2014. Radiologic (presence of peritumoural oedema and volume change following radiotherapy) and histopathologic (tumour volume, grade and surgical margin) parameters were recorded. Outcomes were the events of local recurrence, amputation, metastasis and death.

Results

Local recurrence rate was low (12%) and marginal excision gave equal local control to wide excision. Pelvic localization was associated with a higher risk for amputation. The absence of peritumoural oedema on MRI defined a subgroup of tumours with more favourable oncologic outcome. Reduction of tumour volume following radiotherapy was also associated with better patient survival. Both these radiologic parameters were associated with lower tumour grade. Tumour necrosis was not significant for patient survival. The local complication rate, mainly wound healing problems and infection, was high (40%), but did not lead to any amputation.

Conclusion

Preoperative radiotherapy of high-risk soft-tissue sarcomas allows for good local control rate at the expense of local wound complications, which are however manageable. Marginal excision is sufficient for local control. Absence of peritumoural oedema on MRI, as well as tumour size reduction following radiotherapy are associated to superior patient survival and can be used ass early prognostic factors.

Electronic supplementary material

The online version of this article (10.1186/s13569-018-0106-x) contains supplementary material, which is available to authorized users.

Different patterns of clonal evolution among different sarcoma subtypes followed for up to 25 years

To compare clonal evolution in tumors arising through different mechanisms, we selected three types of sarcoma-amplicon-driven well-differentiated liposarcoma (WDLS), gene fusion-driven myxoid liposarcoma (MLS), and sarcomas with complex genomes (CXS)-and assessed the dynamics of chromosome and nucleotide level mutations by cytogenetics, SNP array analysis and whole-exome sequencing. Here we show that the extensive single-cell variation in WDLS has minor impact on clonal key amplicons in chromosome 12. In addition, only a few of the single nucleotide variants in WDLS were present in more than one lesion, suggesting that such mutations are of little significance in tumor development. MLS displays few mutations other than the FUS-DDIT3 fusion, and the primary tumor is genetically sometimes much more complex than its relapses, whereas CXS in general shows a gradual increase of both nucleotide- and chromosome-level mutations, similar to what has been described in carcinomas.

The effect of radiotherapy on fat content and fatty acids in myxoid liposarcomas quantified by MRI

BACKGROUND

Myxoid liposarcomas are highly radiosensitive. Consequently radiotherapy is often used pre-operatively to reduce tumor volume and lessen the post-operative deficit. In soft-tissue sarcomas therapy response is mainly evaluated using magnetic resonance imaging (MRI) and the fundamental criterion for a positive response is decreased tumor size. In myxoid liposarcomas an increased fat content is also known to occur as a response to radiotherapy.

OBJECTIVE

To highlight the difficulties of MRI for therapy response evaluation in irradiated myxoid liposarcomas, by using MRI Dixon techniques enabling objective quantification of proton density fat fraction (%) and the number of double bonds (ndb; unsaturation degree) of fatty acids. Secondly, to compare quantitative fat fraction measurements versus visual grading of fat content on T1-weighted images.

CASE DESCRIPTIONS

Prior to surgery, two patients with myxoid liposarcoma were treated with 50Gy. Following radiotherapy, both tumors on MRI showed reduced size, elevated fat fraction and transformed fat fraction histograms with diverse changes of ndb, while histopathological specimens showed discordant treatment effects; one case having good response and the other having poor response.

CONCLUSIONS

A decrease in tumor size and increase in fat content on MRI cannot be interpreted as positive therapy response in radiotherapy of myxoid liposarcomas. Our data also give further supporting evidence that differentiation and maturation of tumor cells is the cause for the lipoma-like areas seen after radiotherapy. Finally, quantitative MRI Dixon techniques are preferable to visual grading for estimating the fat content in lipomatous tumors.

Improved Prognosis for Patients with Ewing Sarcoma in the Sacrum Compared with the Innominate Bones: The Scandinavian Sarcoma Group Experience

BACKGROUND

Treatment of Ewing sarcoma of the pelvic bones remains one of the most difficult tasks in the treatment of bone sarcomas. Whether surgery or radiation therapy is the best local treatment is still a matter of debate. The aim of the present study was to compare sacral and nonsacral sites with regard to the treatment and outcome of pelvic Ewing sarcomas.

METHODS

Patients with Ewing sarcoma of the osseous pelvis diagnosed between 1986 and 2011 were identified through the Scandinavian Sarcoma Group registry. Data regarding tumor size, local treatment (surgery or radiation therapy), metastatic disease, surgical margins, local recurrence, and overall survival were analyzed.

RESULTS

Of the 117 patients examined, eighty-eight had tumors in the innominate bones and twenty-nine, in the sacrum. Radiation therapy was the sole local treatment for 40% of the innominate bone tumors in contrast to 79% of the sacral tumors. The five-year disease-free survival rate in the latter group (66%) was greater than that in the group with tumors in the innominate bones (40%) (p = 0.02 adjusted for size).

CONCLUSIONS

Disease-free survival among patients with Ewing sarcoma was improved when the tumor was localized in the sacrum compared with the innominate bones, where these tumors are generally larger. Local radiation therapy alone appears to result in good local tumor control and may be the treatment of choice for sacral tumors.

Current Strategies for the Treatment of Aneurysmal Bone Cysts

Aneurysmal bone cysts are benign bone tumors that usually present in childhood and early adulthood. They usually manifest as expansile osteolytic lesions with a varying potential to be locally aggressive. Since their first description in 1942, a variety of treatment methods has been proposed. Traditionally, these tumors were treated with open surgery. Either intralesional surgical procedures or en bloc excisions have been described. Furthermore, a variety of chemical or physical adjuvants has been utilized in order to reduce the risk for local recurrence after excision. Currently, there is a shift to more minimally invasive procedures in order to avoid the complications of open surgical excision. Good results have been reported during percutaneous surgery, or the use of embolization. Recently, sclerotherapy has emerged as a promising treatment, showing effective consolidation of the lesions and functional results that appear to be superior to the ones of open surgery. Lastly, non-invasive treatment, such as pharmaceutical intervention with denosumab or bisphosphonates has been reported to be effective in the management of the disease. Radiotherapy has also been shown to confer good local control, either alone or in conjunction to other treatment modalities, but is associated with serious adverse effects. Here, we review the current literature on the methods of treatment of aneurysmal bone cysts. The indication for each type of treatment along reported outcome of the intervention, as well as potential complications are systematically presented. Our review aims to increase awareness of the different treatment modalities and facilitate decision-making regarding each individual patient.

Reconstruction of metastatic acetabular defects using a modified Harrington procedure

BACKGROUND AND PURPOSE

Metastases engaging the acetabulum result in significant disability. We investigated the outcome after curettage and reconstruction of the defect with a protrusio cage, retrograde screws, and a cemented total hip arthroplasty.

PATIENTS AND METHODS

We retrospectively identified 70 consecutive patients who were surgically treated for metastatic disease of the acetabulum between 1995 and 2012 using the above technique. The type of primary tumor, extent of the disease, degree of acetabular erosion, and type of implant used were identified. Patient and implant survival, complications, and functional outcome were recorded.

RESULTS

There were no mortalities in the perioperative period (30 days after surgery). Median overall patient survival was 12 months. Prosthesis survival was 92% at 1 year and 89% at 5 years. One third of the patients suffered a complication, the most frequent one being dislocation. The functional outcome was good. Multiple skeletal or visceral metastases and specific types of cancer were associated with poor patient survival.

INTERPRETATION

Reconstruction of metastatic acetabular defects using a protrusio cage stabilized with retrograde screws and a cemented total hip arthroplasty is a safe procedure that provides efficient relief of symptoms. Patients with extensive disease, especially when diagnosed with specific types of cancer, have a very poor prognosis. The complication rate is substantial, the most frequent being dislocation. However, revision surgery is seldom required and prosthesis survival is high.

RNA sequencing of sarcomas with simple karyotypes: identification and enrichment of fusion transcripts

Gene fusions are neoplasia-associated mutations arising from structural chromosomal rearrangements. They have a strong impact on tumor development and constitute important diagnostic markers. Malignant soft tissue tumors (sarcomas) constitute a heterogeneous group of neoplasms with >50 distinct subtypes, each of which is rare. In addition, there is considerable morphologic overlap between sarcomas and benign lesions. Several subtypes display distinct gene fusions, serving as excellent biomarkers. The development of methods for deep sequencing of the complete transcriptome (RNA-Seq) has substantially improved the possibilities for detecting gene fusions. With the aim of identifying new gene fusions of biological and clinical relevance, eight sarcomas with simple karyotypes, ie, only one or a few structural rearrangements, were subjected to massively parallel paired-end sequencing of mRNA. Three different algorithms were used to identify fusion transcripts from RNA-Seq data. Three novel (KIAA2026-NUDT11, CCBL1-ARL1, and AFF3-PHF1) and two previously known fusions (FUS-CREB3L2 and HAS2-PLAG1) were found and could be verified by other methods. These findings show that RNA-Seq is a powerful tool for detecting gene fusions in sarcomas but also suggest that it is advisable to use more than one algorithm to analyze the output data as only two of the confirmed fusions were reported by more than one of the gene fusion detection software programs. For all of the confirmed gene fusions, at least one of the genes mapped to a chromosome band implicated by the karyotype, suggesting that sarcomas with simple karyotypes constitute an excellent resource for identifying novel gene fusions.

Giant hydatid cyst of the pelvis, femur and retroperitoneal space: surgical treatment with extended hemipelvectomy

Hydatid disease of the bone is a very rare manifestation of the disease, and is often associated with debilitating symptoms. We present a rare case of skeletal hydatidosis in a 56-year-old man who had been misdiagnosed for many years. Massive involvement of the pelvic bones and soft tissues was evident. An extended hemipelvectomy was performed in order to achieve resection of the affected segments with a clear surgical margin. The patient recovered uneventfully and there are no signs of recurrence of the disease.

Reconstruction with modular megaprostheses for sarcomas of the lower extremity

Limb-preserving surgery using modular megaprostheses for the reconstruction of large skeletal defects is currently the preferred treatment for sarcomas. The authors report the postoperative outcomes after skeletal resection for lower extremity sarcomas and the use of the METS cemented modular implant system (Stanmore Implants, Hertfordshire, United Kingdom) for reconstruction. They retrospectively studied 52 consecutive patients operated on from 2003 to 2012. There were 27 distal femur prostheses, 13 proximal femur, 11 proximal tibia, and 1 total femur implants. Patients were followed for a mean of 4.3 years. Overall patient survival, prosthesis survival, limb salvage rate, and secondary complications were documented. Five years postoperatively, prosthesis survival was 79%. Complications warranting implant revision surgery were documented in 15% of patients, whereas complications warranting surgery of any kind were observed in 27% of the patients. Nonmechanical complications, namely local relapse of the tumor and prosthetic infection, were the most common cause of prosthetic failure, accounting for 88% of major revision surgeries and 100% of amputations. Mechanical complications were rare, observed in only 6% of patients. No patients required secondary revision surgery. The limb salvage rate was 89%. Overall patient survival was 79% at 5 years and 71% at 10 years. The low risk for mechanical complications and the high limb salvage rate support the use of the METS modular megaprostheses for the reconstruction of skeletal defects following lower limb sarcoma surgery.

Treatment of an aggressive aneurysmal bone cyst with percutaneous injection of polidocanol: a case report

Introduction

Aneurysmal bone cysts are benign tumours that usually present in childhood. Aggressive forms have been described, which are often treated with surgery that entails major resection and reconstruction. Polidocanol sclerotherapy has recently been reported to have excellent results and promises to replace operative treatments, but its efficacy in the case of aggressive aneurysmal bone cysts has not been documented.

Case presentation

An 18-year-old woman from Sweden presented with pain in her shoulder and a rapidly progressing cystic bone lesion. The differential diagnosis was a rare, aggressive form of aneurysmal bone cyst or a sarcoma of the proximal humerus. She was successfully treated using sequential percutaneous injections of polidocanol after exclusion of malignancy.

Conclusions

Management of aggressive aneurysmal bone cysts has thus far relied on open surgery. We propose that non-operative treatment with polidocanol is efficient even in the aggressive form of the aneurysmal bone cyst.

Recurrent PRDM10 gene fusions in undifferentiated pleomorphic sarcoma

PURPOSE

Undifferentiated pleomorphic sarcoma (UPS) is defined as a sarcoma with cellular pleomorphism and no identifiable line of differentiation. It is typically a high-grade lesion with a metastatic rate of about one third. No tumor-specific rearrangement has been identified, and genetic markers that could be used for treatment stratification are lacking. We performed transcriptome sequencing (RNA-Seq) to search for novel gene fusions.

EXPERIMENTAL DESIGN

RNA-Seq, FISH, and/or various PCR methodologies were used to search for gene fusions and rearrangements of the PRDM10 gene in 84 soft tissue sarcomas.

RESULTS

Using RNA-Seq, two cases of UPS were found to display novel gene fusions, both involving the transcription factor PRDM10 as the 3' partner and either MED12 or CITED2 as the 5' partner gene. Further screening of 82 soft tissue sarcomas for rearrangements of the PRDM10 locus revealed one more UPS with a MED12/PRDM10 fusion. None of these genes has been implicated in neoplasia-associated gene fusions before.

CONCLUSIONS

Our results suggest that PRDM10 fusions are present in around 5% of UPS. Although the fusion-positive cases in our series showed the same nuclear pleomorphism and lack of differentiation as other UPS, it is noteworthy that all three were morphologically low grade and that none of the patients developed metastases. Thus, PRDM10 fusion-positive sarcomas may constitute a clinically important subset of UPS.

[Most musculoskeletal soft tissue tumors are benign]

Most musculoskeletal soft tissue tumors are benign, lipoma being the most common. Malignant soft tissue tumors may be difficult to clinically distinguish from benign. Scandinavian recommendations are that all lesions suspicious for sarcoma be referred to a sarcoma center. This has led to improved tumor control and less post-operative functional deficits. Magnetic resonance imaging (MRI) can reliably diagnose lipomas, and further work-up is not necessary. Lipomas can be treated at the local hospital. All deep seated musculoskeletal tumors (under the muscle fascia) not unequivocally lipomas should be referred to a sarcoma center. All superficial (subcutaneous) musculoskeletal tumors larger than 5 cm and not unequivocally lipomas should be referred to a sarcoma center.

Fusions involving protein kinase C and membrane-associated proteins in benign fibrous histiocytoma

Benign fibrous histiocytoma (BFH) is a mesenchymal tumor that most often occurs in the skin (so-called dermatofibroma), but may also appear in soft tissues (so-called deep BFH) and in the skeleton (so-called non-ossifying fibroma). The origin of BFH is unknown, and it has been questioned whether it is a true neoplasm. Chromosome banding, fluorescence in situ hybridization, single nucleotide polymorphism arrays, RNA sequencing, RT-PCR and quantitative real-time PCR were used to search for recurrent somatic mutations in a series of BFH. BFHs were found to harbor recurrent fusions of genes encoding membrane-associated proteins (podoplanin, CD63 and LAMTOR1) with genes encoding protein kinase C (PKC) isoforms PRKCB and PRKCD. PKCs are serine-threonine kinases that through their many phosphorylation targets are implicated in a variety of cellular processes, as well as tumor development. When inactive, the amino-terminal, regulatory domain of PKCs suppresses the activity of their catalytic domain. Upon activation, which requires several steps, they typically translocate to cell membranes, where they interact with different signaling pathways. The detected PDPN-PRKCB, CD63-PRKCD and LAMTOR1-PRKCD gene fusions are all predicted to result in chimeric proteins consisting of the membrane-binding part of PDPN, CD63 or LAMTOR1 and the entire catalytic domain of the PKC. This novel pathogenetic mechanism should result in constitutive kinase activity at an ectopic location. The results show that BFH indeed is a true neoplasm, and that distorted PKC activity is essential for tumorigenesis. The findings also provide means to differentiate BFH from other skin and soft tissue tumors. This article is part of a Directed Issue entitled: Rare cancers.

Sclerotherapy with polidocanol for treatment of aneurysmal bone cysts

BACKGROUND AND PURPOSE

Recent data suggest that percutaneous sclerotherapy is a safe alternative to surgery for treatment of aneurysmal bone cysts (ABCs). We present our experience of this method.

METHODS

We retrospectively analyzed data from 38 consecutive patients treated with repeated injections of polidocanol. Each injection consisted of 2-4 mg polidocanol per kg body weight. Radiological and clinical assessments were performed until healing.

RESULTS

All cycts except 1 healed after a median of 4 (1-11) injections. A lesion failed to heal in 1 patient, who was operated. 3 patients experienced minor local inflammatory reactions.

INTERPRETATION

Our results show that percutaneus sclerotherapy with polidocanol has high efficacy in the treatment of ABCs, with a low frequency of side effects. Our findings corroborate data presented in previous publications. We believe that the method will be especially valuable in ABCs of the pelvis and sacrum, where surgery is associated with considerable morbidity.

Integrative genome and transcriptome analyses reveal two distinct types of ring chromosome in soft tissue sarcomas

Gene amplification is a common phenomenon in malignant neoplasms of all types. One mechanism behind increased gene copy number is the formation of ring chromosomes. Such structures are mitotically unstable and during tumor progression they accumulate material from many different parts of the genome. Hence, their content varies considerably between and within tumors. Partly due to this extensive variation, the genetic content of many ring-containing tumors remains poorly characterized. Ring chromosomes are particularly prevalent in specific subtypes of sarcoma. Here, we have combined fluorescence in situ hybridization (FISH), global genomic copy number and gene expression data on ring-containing soft tissue sarcomas and show that they harbor two fundamentally different types of ring chromosome: MDM2-positive and MDM2-negative rings. While the former are often found in an otherwise normal chromosome complement, the latter seem to arise in the context of general chromosomal instability. In line with this, sarcomas with MDM2-negative rings commonly show complete loss of either CDKN2A or RB1 -both known to be important for genome integrity. Sarcomas with MDM2-positive rings instead show co-amplification of a variety of potential driver oncogenes. More than 100 different genes were found to be involved, many of which are known to induce cell growth, promote proliferation or inhibit apoptosis. Several of the amplified and overexpressed genes constitute potential drug targets.

Megaprosthetic reconstruction for periprosthetic or highly comminuted fractures of the hip and knee

OBJECTIVES

To present the experience of a tertiary referral hospital in the management of a case series with hip or knee fractures by using modular megaprosthesis.

PATIENTS AND METHODS

Seventeen consecutive patients with highly comminuted fractures of the knee (n = 2), periprosthetic fractures of knee (n = 10) or hip (n = 5) were included. Fractures were managed with modular megaprosthesis (including total hip in 2 cases). Postoperative complications like infection and instability and outcome measures like return to previous mobility and living were recorded.

RESULTS

The mean age at time of surgery was 77 years (25-91), and mean follow-up was 44 months (13-98). We had no intra-operative complications. There were 3 deep periprosthetic infections, 1 hip and 2 knee. In the hip group, including total femur patients, we had 2 dislocations (2/7), both managed with closed reduction. No aseptic loosening was seen. 15/17 patients regained walking ability, and 16 were discharged to independent living. Nine patients have died at the time of follow-up.

CONCLUSIONS

In these often old and physically compromised patients with highly comminuted fractures or complicated periprosthetic fractures, modular megaprosthesis could be a good surgical option. It can provide immediate stability and allow early mobilization.

The MDM2 SNP309 G allele is not preferentially amplified in bone and soft tissue tumors

The transcriptional enhancer region in intron 1 of the proto-oncogene MDM2 contains a polymorphic site (SNP309) that may harbor a G or a T nucleotide. Previous studies have shown that the G allele confers a higher affinity for the Sp1 transcription factor, resulting in an increased transcriptional activity of MDM2. A constitutional G allele has also been associated with earlier onset of various cancer types, and studies of sarcomas have shown an enrichment of the G allele in tumors with MDM2 amplification, notably atypical lipomatous tumor (also known as well-differentiated liposarcoma). In the present study, we analyzed the SNP309 genotype in blood samples and tumor tissue from 57 patients with bone or soft tissue tumors showing amplification of MDM2. We did not observe any constitutional enrichment of the G allele. More importantly, there was no preferential amplification of the G allele in tumor tissue from TG heterozygotes. The expression levels of MDM2 messenger RNA were not higher in tumors with amplification of the G allele than in tumors with amplification of the T allele. Thus, we could not find any evidence for a selective advantage of the SNP309 G allele in bone and soft tissue tumors with MDM2 amplification.

Diagnosis of high-grade osteosarcoma by radiology and cytology: a retrospective study of 52 cases

The diagnostic value of combined radiology and fine needle aspiration cytology (FNAC) was retrospectively assessed in a consecutive series of 52 patients with high-grade osteosarcoma. The series was divided into typical and atypical osteosarcomas according to radiological features and site. Thirty-two of 33 radiologically typical osteosarcoma cases were correctly diagnosed by cytology; one lesion was diagnosed as sarcoma NOS. Nineteen osteosarcoma cases were radiographically atypical. Six of these were diagnosed as osteosarcoma and another six as sarcoma NOS. In three cases another type of sarcoma was suggested. One case was falsely classified as benign. FNAC of three cases were non-diagnostic. Overall, the diagnostic difficulties pertained to the radiologically atypical cases. Notably, four of these also posed considerable difficulties in the histopathological assessment prompting external consultation. Our study suggests that open biopsy can be obviated in high-grade osteosarcomas exhibiting typical radiological features, i.e., in two-thirds.

Results of the Scandinavian Sarcoma Group XIV protocol for classical osteosarcoma: 63 patients with a minimum follow-up of 4 years

BACKGROUND AND PURPOSE

The Scandinavian Sarcoma Group (SSG) XIV protocol is based on experience from previous SSG trials and other osteosarcoma intergroup trials, and has been considered the best standard of care for patients with extremity localized, non-metastatic osteosarcoma. We analyzed the outcome in 63 consecutive patients. Patients and methods From 2001 through 2005, 63 patients recruited from centers in Sweden, Norway, and Finland were included. They received preoperative chemotherapy consisting of 2 cycles of paired methotrexate (12 g/m²), cisplatin (90 mg/m²), and doxorubicin (75 mg/m²). 3 cycles were administered postoperatively, and poor histological responders were given 3 additional cycles of ifosfamide (10-12 g/m²) as a salvage strategy.

RESULTS

With a median follow-up of 77 months for survivors, the estimated metastasis-free and sarcoma-related survival at 5 years was 70% and 76%, respectively. 53 patients were treated with limb salvage surgery or rotationplasty and 2 patients experienced a local recurrence. 3 toxic deaths were recorded, all related to acute toxicity from chemotherapy. The 5-year metastasis-free survival of poor histological responders receiving add-on treatment with ifosfamide was 47%, as compared to 89% for good histological responders.

INTERPRETATION

Outcome from the SSG XIV protocol compares favorably with the results of previous SSG trials and other published osteosarcoma trials. However, salvage therapy given to poor responders did not improve outcome to a similar degree as for good responders. In a multi-institutional setting, more than four-fifths of the patients were operated with limb salvage surgery or rotationplasty, with few local recurrences.

Telomeric associations correlate with telomere length reduction and clonal chromosome aberrations in giant cell tumor of bone

Giant cell tumor of bone (GCTB) is characterized cytogenetically by frequent telomeric associations (tas). To explore the mechanisms behind the formation of tas in GCTB and to investigate their karyotypic consequences, the frequencies of tas and clonal aberrations other than tas in 20 GCTBs were compared to telomere length and status, as assessed by quantitative PCR, fluorescence in situ hybridization (FISH), and expression levels of four genes involved in telomere maintenance. Based on the G-banding results, the tumors were divided into two groups, one with a high frequency of tas and one with a low frequency. Clonal aberrations were found to be restricted to the group with a high level of tas, and the same group showed a significantly larger reduction in telomere length in tumor cells compared to peripheral blood cells. Furthermore, 65 out of 66 tas analyzed by FISH were negative for telomeric sequences. The expression levels of TERT, TERF1, TERF2, and POT1 did not correlate with telomere length or the frequency of tas. Thus, the present findings provide strong support for the notion that decreased telomere length is a prerequisite for tas in GCTBs and that the clonal changes occurring in GCTBs are derived from tas.

Genomic profiling of chondrosarcoma: chromosomal patterns in central and peripheral tumors

PURPOSE

Histologic grade is currently the best predictor of clinical course in chondrosarcoma patients. Grading suffers, however, from extensive interobserver variability and new objective markers are needed. Hence, we have investigated DNA copy numbers in chondrosarcomas with the purpose of identifying markers useful for prognosis and subclassification.

EXPERIMENTAL DESIGN

The overall pattern of genomic imbalances was assessed in a series of 67 chondrosarcomas using array comparative genomic hybridization. Statistical analyses were applied to evaluate the significance of alterations detected in subgroups based on clinical data, morphology, grade, tumor size, and karyotypic features. Also, the global gene expression profiles were obtained in a subset of the tumors.

RESULTS

Genomic imbalances, in most tumors affecting large regions of the genome, were found in 90% of the cases. Several apparently distinctive aberrations affecting conventional central and peripheral tumors, respectively, were identified. Although rare, recurrent amplifications were found at 8q24.21-q24.22 and 11q22.1-q22.3, and homozygous deletions of loci previously implicated in chondrosarcoma development affected the CDKN2A, EXT1, and EXT2 genes. The chromosomal imbalances in two distinct groups of predominantly near-haploid and near-triploid tumors, respectively, support the notion that polyploidization of an initially hyperhaploid/hypodiploid cell population is a common mechanism of chondrosarcoma progression. Increasing patient age as well as tumor grade were associated with adverse outcome, but no copy number imbalance affected metastasis development or tumor-associated death.

CONCLUSION

Despite similarities in the overall genomic patterns, the present findings suggest that some regions are specifically altered in conventional central and peripheral tumors, respectively.

Malignant Fibrous Histiocytoma, Aggressive Fibromatosis and Benign Fibrous Tumors Express mRNA for the Metalloproteinase Inducer EMMPRIN and the Metalloproteinases MMP-2 and MT1-MMP

PURPOSE

Extracellular matrix metalloproteinase inducer (EMMPRIN) has been shown to stimulate fibroblasts to production of matrix metalloproteinases (MMPs). MMPs comprise a family of proteolytic enzymes implicated in the degradation of extracellular matrix which has been proposed to be one of the essential steps in tumor invasion and metastases. In the present study we investigated the expression and location of mRNAs for EMMPRIN, matrix metalloproteinase-2 (MMP-2), and membrane-type 1 matrix metalloproteinase (MT1-MMP) in mesenchymal tumors with different tendencies to recur or metastasize.

SUBJECTS

Eight malignant fibrous histiocytomas (MFH), seven aggressive fibromatosis (AF), and six benign fibrous tumors (BF).

METHOD

The mRNA-expression of EMMPRIN, MMP-2 and MT1-MMP were studied using mRNA in situ hybridization technique.

RESULTS

The mRNA-expression of EMMPRIN, MMP-2 and MT1-MMP respectively were found at varying frequency and level in all tumor types. The mRNAs corresponding to EMMPRIN and MMP-2 were seen in neoplastic cells as well as in endothelial cells both inside and outside the tumor pseudo-capsule, whereas MT1-MMP was seen only within the tumors. The estimated mRNA levels of EMMPRIN and MMP-2 covariated significantly. Overall, the highest expression was found in the MFH tumors and the lowest levels in the BF tumors.

DISCUSSION

These findings suggest that the MMP-inducer EMMPRIN and the extracellular matrix degrading system involving the metalloproteinases MMP-2 and MT1-MMP is frequently activated in mesenchymal tumors. The covariation between EMMPRIN and MMP-2 support previous findings that EMMPRIN may be an inducer of MMP-2. The high levels of MMP-2 mRNA in MFH indicate a relationship between the proteolytic activity of MMP-2 and the tumor aggressiveness.

Assessment of the clinical and molecular impact of different cytogenetic subgroups in a series of 272 lipomas with abnormal karyotype

Conventional lipomas harbor karyotypic changes that could be subdivided into four, usually mutually exclusive, categories: rearrangement, in particular through translocations, of chromosome bands 12q13-15, resulting in deregulation of the HMGA2 gene, loss of material from or rearrangement of chromosome 13, supernumerary ring or giant marker chromosomes, and aberrations of chromosome band 6p21. In the present study, 272 conventional lipomas, two-thirds of them deep-seated, with acquired clonal chromosome changes were assessed with regard to karyotypic and clinical features. A nonrandom distribution of breakpoints and imbalances could be confirmed, with 83% of the cases harboring one or more of the previously known cytogenetic hallmarks. Correlation with clinical features revealed that lipomas with rings/giant markers were larger, occurred in older patients, were more often deep-seated, and seemed to have an increased tendency to recur locally, compared with tumors with other chromosome aberrations. The possible involvement of the HMGA2 gene in cases that did not show any of the characteristic cytogenetic changes was further evaluated by locus-specific metaphase fluorescence in situ hybridization (FISH) and RT-PCR, revealing infrequent cryptic disruption of the gene but abundant expression of full length or truncated transcripts. By FISH, we could also show that breakpoints in bands 10q22-23 do not affect the MYST4 gene, whereas breakpoints in 6p21 or 8q11-12 occasionally target the HMGA1 or PLAG1 genes, respectively, also in conventional lipomas.

Identification of a novel amplicon at distal 17q containing theBIRC5/SURVIVINgene in malignant peripheral nerve sheath tumours

Previous studies have suggested that amplification of genes, notably the TOP2A gene, on chromosome arm 17q may be important for the development of malignant peripheral nerve sheath tumour (MPNST). In order to study the frequency, distribution, and chromosomal organization of rearrangements at 17q, interphase and metaphase fluorescence in situ hybridization (FISH) were used to evaluate copy number changes at 17q in 28 MPNSTs. Increased copy numbers were seen for the ERBB2 and TOP2A genes in eight and nine cases, respectively, supporting a potential role for these two genes in MPNST tumourigenesis. Net gain of distal 17q material was observed in 16 of the 28 MPNSTs, with high-level gain in three cases, and was associated with poor outcome. Among the 26 patients for whom follow-up data were available, gain of distal 17q was present in 11 of 12 tumours that had metastasized, compared with 4 of 14 of those that had not metastasized. Detailed FISH mapping analysis of metaphase spreads identified a 2 Mb commonly gained/amplified region at 17q25. Among the genes mapping to this region, BIRC5, which encodes the baculoviral IAP repeat-containing protein 5/survivin protein, is a strong candidate target gene for amplification, as it has been previously shown to be overexpressed in neurofibromatosis type 1-associated MPNST. Three other genes that co-amplified with BIRC5 represent other potential candidate genes: PTDSR involved in apoptosis; SEPT9 overexpressed in human malignant brain tumours; and SOCS3 involved in cell survival and differentiation of neurons.

Prognostic significance of chromosome aberrations in high-grade soft tissue sarcomas

PURPOSE

To investigate whether previously observed correlations between tumor karyotype and risk of metastases could be reproduced in an independent set of high-grade soft tissue sarcomas (STSs).

PATIENTS AND METHODS

In a previous study on high-grade STSs with clonal chromosome aberrations, we identified a number of cytogenetic variables, besides tumor grade and size, that were associated with significantly increased risk of metastases. In the present study, we have tested the predictive value of these cytogenetic variables in a new set of 156 high-grade STSs, all located in the extremities or trunk wall.

RESULTS

Of the 10 cytogenetic variables that turned out to provide prognostic information in the previous series, encompassing 122 trunk wall or extremity STSs, three were significantly associated with metastases also in the new series. In a final Cox regression analysis including these three cytogenetic variables, as well as tumor grade and size, on the combined series of 278 high-grade STSs, four parameters were found to be significantly associated with metastasis risk: tumor grade 3, tumor size > or = 5 cm, breakpoint in region 1p1, and gain of region 6p1.

CONCLUSION

Our findings suggest that independent prognostic information may be gained from cytogenetic analysis of high-grade STS.

Neoadjuvant chemotherapy with high-dose Ifosfamide, high-dose methotrexate, cisplatin, and doxorubicin for patients with localized osteosarcoma of the extremity: a joint study by the Italian and Scandinavian Sarcoma Groups

PURPOSE

To explore the effect of high-dose ifosfamide in first-line treatment for patients < or = 40 years of age with nonmetastatic osteosarcoma of the extremity.

PATIENTS AND METHODS

From March 1997 to September 2000, 182 patients were evaluated. Primary treatment consisted of two blocks of high-dose ifosfamide (15 g/m2), methotrexate (12 g/m2), cisplatin (120 mg/m2), and doxorubicin (75 mg/m2). Postoperatively, patients received two cycles of doxorubicin (90 mg/m2), and three cycles each of high-dose ifosfamide, methotrexate, and cisplatin (120 to 150 mg/m2). Granulocyte colony-stimulating factor support was mandatory after the high-dose ifosfamide/cisplatin/doxorubicin combination.

RESULTS

No disease progression was recorded during primary chemotherapy, 164 patients (92%) underwent limb-salvage surgery, four patients (2%) underwent rotation plasty, and 11 patients (6%) had limbs amputated. Three (1.6%) patients died as a result of treatment-related toxicity, and one died as a result of pulmonary embolism after pathologic fracture. Grade 4 neutropenia and thrombocytopenia followed 52% and 31% of all courses, respectively, and mild to severe nephrotoxicity was recorded in 19 patients (10%). The median received dose-intensity compared with protocol was 0.82. With a median follow-up of 55 months, the 5-year probability of event-free survival was 64% (95% CI, 57% to 71%) and overall survival was 77% (95% CI, 67% to 81%), whereas seven patients (4%) experienced local recurrence.

CONCLUSION

The addition of high-dose ifosfamide to methotrexate, cisplatin, and doxorubicin in the preoperative phase is feasible, but with major renal and hematologic toxicities, and survival rates similar to those obtained with four-drug regimens using standard-dose ifosfamide. Italian Sarcoma Group/Scandinavian Sarcoma Group study I showed that in a multicenter setting, more than 90% of patients with osteosarcoma of the extremity can undergo conservative surgery.

Insulin-like growth factor type 1 receptor expression correlates to good prognosis in highly malignant soft tissue sarcoma

PURPOSE

To evaluate known and suggested prognostic markers, especially insulin-like growth factor type 1 receptor (IGF-1R), in highly malignant soft tissue sarcomas (STS).

EXPERIMENTAL DESIGN

A cohort of 101 patients with primary STS of high malignancy grade was studied with respect to development of metastasis, local recurrence, and survival during a minimum of 5 years follow-up. All tumors were analyzed by immunohistochemistry for expression of Ki-67, p53, p27, Bcl-2, IGF-1R, and microvessel density. The traditional clinical variables size, malignancy grade (3 or 4), necrosis, mitotic frequency, infiltrative tumor growth, vascular invasion, depth, and surgical margins were also evaluated.

RESULTS

A significant association was shown between high expression of IGF-1R and favorable outcome. Among STS with positive IGF-1R immunoreactivity, cases with high expression (76-100% positive cells) had the best outcome, whereas cases with the lowest expression (1-25% positive cells) had the worst. As expected, large tumor size (>11 cm), presence of necrosis, high mitotic count, intralesional surgery, and deep location were all significantly associated with poor outcome, both in univariate and multivariate analyses. No difference in outcome was observed between cases of malignancy grade 3 versus 4, whereas the included and more objective variables necrosis and mitotic count were found to be reliable prognostic markers.

CONCLUSION

IGF-1R expression is a common feature of highly malignant STS. Further elucidation of the role of IGF-1R and the IGF system in STS may both provide a basis for development of new prognostic tools in STS, as well as shed light on the basic mechanisms of the STS development.

Fusion, disruption, and expression of HMGA2 in bone and soft tissue chondromas

Soft tissue and skeletal chondromas are rare entities, and only 21 cases with abnormal karyotypes have been reported. A survey of these, and 10 new cases reported herein, showed that the 12q13-15 segment is nonrandomly involved in structural rearrangements in chondromas. The HMGA2 (HMGI-C) locus in 12q15 is frequently rearranged in other benign mesenchymal tumors, and this study aimed at characterizing the expression of HMGA2 in chondromatous tumors. The material consisted of 8 soft tissue and 6 skeletal chondromas, as well as of 14 skeletal chondrosarcomas. All cases had been cytogenetically analyzed. Expression of HMGA2 could be assessed by RT-PCR in 8 chondromas and 13 chondrosarcomas. HMGA2 was expressed in 4 of six soft tissue chondromas, all displaying 12q-rearrangements at cytogenetic analysis. A truncated transcript (exons 1-3), but not a full-length (exons 1-5) transcript, was detected in three of them, suggesting activation through an intragenic rearrangement. One soft tissue chondroma had a t(3;12)(q27;q15), and the RT-PCR analysis revealed an HMGA2-LPP fusion transcript, composed of HMGA2 exons 1-3 and LPP exons 9-11. An identical fusion transcript previously has been identified in lipoma and pulmonary chondroid hamartoma. In the fourth soft tissue chondroma, a full-length transcript was detected, indicating expression of at least one intact allele. Both skeletal chondromas expressed HMGA2. In one of them, a full-length transcript was detected, even though 12q was cytogenetically unaffected. A truncated or full-length transcript was found in 8 of 13 chondrosarcomas, 4 of which displayed 12q rearrangements. Possibly, cryptic rearrangements were present among the many complex marker chromosomes in the remaining 4 cases.

The chimericFUS/CREB3l2gene is specific for low-grade fibromyxoid sarcoma

Low-grade fibromyxoid sarcoma (LGFMS) is a variant of fibrosarcoma that was recognized as a distinct tumor entity only quite recently. We previously described a translocation, t(7;16)(q33;p11), that resulted in a fusion of the FUS and CREB3L2 (also known as BBF2H7) genes in two soft tissue tumors that fulfilled morphologic criteria for LGFMS. To delineate the spectrum of tumors that may harbor the FUS/CREB3L2 gene, we selected 45 low-grade spindle cell sarcomas for reverse transcriptase polymerase chain reaction (RT-PCR) and/or fluorescence in situ hybridization (FISH) analyses; none of these tumors had originally been diagnosed as LGFMS. Furthermore, also included were two benign soft tissue tumors and nine high-grade sarcomas with supernumerary ring chromosomes or 7q3 rearrangement and three tumors diagnosed as LGFMS prior to the genetic analysis. Of the 59 tumors analyzed, 12 were FUS/CREB3L2-positive, all of which were diagnosed at histopathologic re-examination as being LGFMS, of both the classical subtype and the subtype with giant collagen rosettes. The breakpoints in the fusion transcripts were always in exons 6 or 7 of FUS and exon 5 of CREB3L2. The results indicated that FUS/CREB3L2 is specifically associated with LGFMS and that RT-PCR or FISH analysis may be useful for the differential diagnosis.