Radiation-associated sarcomas are characterized by complex karyotypes with frequent rearrangements of chromosome arm 3p

Distinct genomic landscapes in radiation-associated angiosarcoma compared with other radiation-associated sarcoma histologies

MYC amplifications have been frequently detected in radiation (RT)-associated angiosarcomas (ASs) by low-resolution molecular methods. However, large-scale next-generation sequencing (NGS) studies to investigate the genomic landscape of RT-AS are scarce, particularly compared with other RT-associated sarcomas. We performed a detailed comparative genomic investigation of RT-AS versus other RT-associated histotypes, as well as sporadic sarcomas with similar histologies. Our institutional targeted DNA-NGS assay database was searched for RT-associated sarcomas. Clinical outcome data, pathologic diagnosis, and the types and frequencies of genomic alterations, including single nucleotide variants (SNVs) and copy number alterations (CNAs), were analyzed. The cohort consisted of 82 patients, 68 (83%) females and 14 (17%) males, aged 37-88 (mean 64) years. Forty-four RT-ASs (38 from breast) and 38 RT sarcomas of other histologies, including 12 malignant peripheral nerve sheath tumors (RT-MPNSTs), 14 undifferentiated pleomorphic sarcomas (RT-UPSs), and 12 osteosarcomas (RT-OSs), were included. Median time intervals from radiation to initial diagnosis in RT-AS (8.0 years) were significantly lower than those in RT-MPNST and RT-UPS (12.5 and 18.5 years), respectively. Each RT-sarcoma histotype harbored distinct mutations and CNAs. RT-associated AS had more frequent MYC, FLT4, CRKL, HRAS, and KMT2D alterations than sporadic AS (enriched in TP53, KDR, ATM, ATRX), whereas the mutational landscapes of MPNST, UPS, and OS were similar in both RT and non-RT settings. CDKN2A/B deletions and TP53 alterations were infrequent in RT-AS compared with other RT sarcomas. Among RT sarcomas, RT-AS harbored the lowest fraction of genome altered (FGA), while RT-MPNST showed the highest FGA. RT-AS had the lowest insertion:SNV and deletion:SNV ratios, while RT-UPS had the highest. The predominant mutational signatures were associated with errors in DNA repair and replication. In conclusion, RT-AS has a distinct genomic landscape compared with other RT sarcomas and sporadic AS. Potential molecular targets for precision medicine may be histotype-dependent. © 2023 The Pathological Society of Great Britain and Ireland.

Radiation-Induced Sarcoma: A Retrospective Population-Based Study Over 34 Years in a Single Institution

AIMS

About a half of all cancer patients receive radiotherapy as part of their oncological treatment. Because of the carcinogenic effect of ionising radiation, there is a rare, but definite, risk of developing secondary malignancies, including sarcomas. The aim of this retrospective study was to describe the prevalence, patient and tumour characteristics, as well as prognosis and outcome, of patients with radiation-induced sarcomas (RIS) in a cohort of patients treated in the Sarcoma Centre at Aarhus University Hospital over a period of 34 years.

MATERIALS AND METHODS

All patients who fulfilled the criteria for RIS and were treated for RIS in the period 1979-2013 were included. Patient data were retrieved from the Aarhus Sarcoma Registry and the National Danish Sarcoma Database, crosschecked with the National Register of Pathology and validated using the patients' medical records. The primary end point was the effect of surgery and treatment intent on overall survival. Overall survival is reported using the Kaplan-Meier estimates and compared using the Log-rank test. Descriptive statistics are presented for patients, tumours and treatment characteristics.

RESULTS

Of 2845 patients diagnosed with sarcoma between 1979 and 2013, 64 (2%) were diagnosed with RIS. The median interval from the original malignancy was 11 years. The most common histological type was undifferentiated pleomorphic sarcoma (33%). Curative treatment was intended for 45 patients. Fifty patients underwent surgery, of whom 80% had microscopically radical resection (R0). The 5-year overall survival for the whole cohort was 32%. Patients who underwent surgery had a significantly better overall survival compared with patients who were not treated with surgery. In the univariate Cox proportional hazard analyses, no metastases at diagnosis, surgery and R0 resection were favourable prognostics factors of survival.

CONCLUSION

This study showed that RIS patients are unique in their epidemiology and tumour characteristics. They have a poor prognosis and need special research investigating new intensive treatment strategies to improve the outcome.

Secondary uterine carcinosarcoma after concurrent chemoradiotherapy for cervical cancer: Case reports

•

Secondary uterine sarcomas occur in < 1% of patients treated with CCRT.

•

Secondary uterine sarcomas can occur > 5 years from CCRT.

•

The median survival period from the secondary tumor occurrence was only 4 months.

•

All our patients had heterologous carcinosarcoma of the uterine corpus.

Radiation-induced sarcoma masquerading as osteoradionecrosis: case report and literature review

Background:

Radiation therapy is a commonly used treatment in head and neck oncology, whether used alone or as an adjunct to other treatments. Osteoradionecrosis and radiation-induced malignancy are both rare, late complications of radiation therapy.

Methods:

This paper describes a case of radiation-induced sarcoma of the mandible initially presenting as osteoradionecrosis. In addition, the literature on the identification and treatment of these entities is reviewed.

Results:

The patient underwent excision and reconstruction of the presumed osteoradionecrosis. Final pathology demonstrated radiation-induced sarcoma. The patient suffered tumour recurrence at seven months post-operatively.

Conclusion:

When evaluating a patient with osteoradionecrosis, clinicians should be cognisant of the risk of malignancy. This paper describes the first case of radiation-induced sarcoma presenting as osteoradionecrosis. Primary treatment of radiation-induced sarcoma is wide surgical extirpation, with a very limited role for chemotherapy. Overall survival for this entity is poor.

Genetic features of metachronous esophageal cancer developed in Hodgkin's lymphoma or breast cancer long-term survivors: an exploratory study

Background

Development of novel therapeutic drugs and regimens for cancer treatment has led to improvements in patient long-term survival. This success has, however, been accompanied by the increased occurrence of second primary cancers. Indeed, patients who received regional radiotherapy for Hodgkin’s Lymphoma (HL) or breast cancer may develop, many years later, a solid metachronous tumor in the irradiated field. Despite extensive epidemiological studies, little information is available on the genetic changes involved in the pathogenesis of these solid therapy-related neoplasms.

Methods

Using microsatellite markers located in 7 chromosomal regions frequently deleted in sporadic esophageal cancer, we investigated loss of heterozygosity (LOH) and microsatellite instability (MSI) in 46 paired (normal and tumor) samples. Twenty samples were of esophageal carcinoma developed in HL or breast cancer long-term survivors: 14 squamous cell carcinomas (ESCC) and 6 adenocarcinomas (EADC), while 26 samples, used as control, were of sporadic esophageal cancer (15 ESCC and 11 EADC).

Results

We found that, though the overall LOH frequency at the studied chromosomal regions was similar among metachronous and sporadic tumors, the latter exhibited a statistically different higher LOH frequency at 17q21.31 (p = 0.018). By stratifying for tumor histotype we observed that LOH at 3p24.1, 5q11.2 and 9p21.3 were more frequent in ESCC than in EADC suggesting a different role of the genetic determinants located nearby these regions in the development of the two esophageal cancer histotypes.

Conclusions

Altogether, our results strengthen the genetic diversity among ESCC and EADC whether they occurred spontaneously or after therapeutic treatments. The presence of histotype-specific alterations in esophageal carcinoma arisen in HL or breast cancer long-term survivors suggests that their transformation process, though the putative different etiological origin, may retrace sporadic ESCC and EADC carcinogenesis.

Radiation-induced sarcomas of the head and neck

With improved outcomes associated with radiotherapy, radiation-induced sarcomas (RIS) are increasingly seen in long-term survivors of head and neck cancers, with an estimated risk of up to 0.3%. They exhibit no subsite predilection within the head and neck and can arise in any irradiated tissue of mesenchymal origin. Common histologic subtypes of RIS parallel their de novo counterparts and include osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma/sarcoma nitricoxide synthase, and fibrosarcoma. While imaging features of RIS are not pathognomonic, large size, extensive local invasion with bony destruction, marked enhancement within a prior radiotherapy field, and an appropriate latency period are suggestive of a diagnosis of RIS. RIS development may be influenced by factors such as radiation dose, age at initial exposure, exposure to chemotherapeutic agents and genetic tendency. Precise pathogenetic mechanisms of RIS are poorly understood and both directly mutagenizing effects of radiotherapy as well as changes in microenvironments are thought to play a role. Management of RIS is challenging, entailing surgery in irradiated tissue and a limited scope for further radiotherapy and chemotherapy. RIS is associated with significantly poorer outcomes than stage-matched sarcomas that arise independent of irradiation and surgical resection with clear margins seems to offer the best chance for cure.

Osteogenic tumors of bone

In this paper we provide an overview of benign and malignant osteogenic bone tumors. We describe the diagnostic features, radiographic findings, and pertinent ancillary studies needed to diagnose these bone-forming lesions. We begin with osteoid osteoma and osteoblastoma, which are histologically bland and eminently benign with rare possible exceptions. On the other end of the behavioral spectrum is osteosarcoma, which encompasses many subtypes ranging from high-grade osteogenic osteosarcoma to less overtly osteogenic lesions such as telangiectatic and small cell osteosarcoma. While classic osteogenic osteosarcoma can be easily recognized by its high grade morphology and formation of extracellular lace-like osteoid, its variants may pose diagnostic dilemmas as their differential diagnoses can include benign, fibrous, and vascular lesions, among others. Recognition of these variants is essential to avoid diagnostic pitfalls. In equivocal cases, some forms of osteosarcoma have shown molecular alterations that may prove diagnostically useful.

Genetic predisposition to radiation induced sarcoma: possible role for BRCA and p53 mutations

The estimated incidence of radiation-associated sarcoma (RAS) is 0.03-0.2 % in 5 years post treatment. Most cancer predisposing genes are involved in DNA repair; therefore, elevated RAS risk in these patients is plausible. Cases of angiosarcoma post breast cancer treatment were reported in BRCA1 and BRCA2 carriers. We report the genetic evaluation of seven cases with suspected RAS from patients counseled in our cancer-genetic clinic. Of 2,885 breast cancer patient, 470 were BRCA1 or two mutation carriers and three were p53 mutation carriers. Of them seven developed sarcoma in the field of irradiation; five in the chest wall and two in other sites. Genetic evaluation revealed BRCA1 mutation in two, BRCA2 mutation in additional patient and a carrier of p53 mutation. The estimation of risk for RAS in patients with genetic predisposition is limited due to the rarity of this event, and the bias in referral to the clinic toward younger age. With these limitations the rate of RAS is 0.43 % (2/470, 95 % CI -0.17 to 1.02, SE = 0.3) in this group in a median follow-up of 8.2 years (range 1 month to 51 years). If we assume irradiation for the breast in 80 % of the patients than rate of RAS in group is proximately 0.53 % (2/376, 95 % CI -0.21 to 1.26, SE = 0.37). A BRCA1 carrier which had sarcoma after irradiation to head and neck carcinoma was not included in these analyses. In conclusion, we found a high frequency of BRCA1/2 mutation among our patients diagnosed with RAS. However, we estimated approximately twofold increase in the risk of RAS in BRCA1/2 carriers which was not significant compared to reports in general population. Therefore, RAS is a rare event in BRCA carriers as in the general population, and should not be considered in the decision regarding irradiation treatment in this population.

Sarcoma risk after radiation exposure

Sarcomas were one of the first solid cancers to be linked to ionizing radiation exposure. We reviewed the current evidence on this relationship, focusing particularly on the studies that had individual estimates of radiation doses. There is clear evidence of an increased risk of both bone and soft tissue sarcomas after high-dose fractionated radiation exposure (10 + Gy) in childhood, and the risk increases approximately linearly in dose, at least up to 40 Gy. There are few studies available of sarcoma after radiotherapy in adulthood for cancer, but data from cancer registries and studies of treatment for benign conditions confirm that the risk of sarcoma is also increased in this age-group after fractionated high-dose exposure. New findings from the long-term follow-up of the Japanese atomic bomb survivors suggest, for the first time, that sarcomas can be induced by acute lower-doses of radiation (<5 Gy) at any age, and the magnitude of the risk is similar to that observed for other solid cancers. While there is evidence that individuals with certain rare familial genetic syndromes predisposing to sarcoma, particularly Nijmegen Breakage Syndrome, are particularly sensitive to the effects of high dose radiation, it is unclear whether this is also true in very low-dose settings (<0.1 Gy). The effects of common low-penetrance alleles on radiosensitivity in the general population have not been well-characterized. Some evidence suggests that it may be possible to identify radiation-induced sarcomas by a distinct molecular signature, but this work needs to be replicated in several dose settings, and the potential role of chemotherapy and tumor heterogeneity needs to be examined in more detail. In summary, radiation exposure remains one of the few established risk factors for both bone and soft tissue sarcomas. Similar to many other cancers children have the highest risks of developing a radiation-related sarcoma. Efforts to limit unnecessary high-dose radiation exposure, particularly in children, therefore remain important given the high fatality rates associated with this disease.

High frequency of MYC gene amplification is a common feature of radiation-induced sarcomas. Further results from EORTC STBSG TL 01/01

Irradiation is a major causative factor among the small subgroup of sarcomas with a known etiology. The prognosis of radiation-induced sarcomas (RIS) is significantly worse than that of their spontaneous counterparts. The most frequent histological subtypes include undifferentiated pleomorphic sarcomas, angiosarcomas, and leiomyosarcomas. A high frequency of MYC amplifications in radiation-induced angiosarcomas, but not in primary angiosarcomas, has recently been described. To investigate whether MYC amplifications are also frequent in RIS other than angiosarcomas, we analyzed the MYC amplification status of 83 RIS and 192 sporadic sarcomas by fluorescence in situ hybridization. We found significantly higher numbers of MYC amplifications in RIS than in sporadic sarcomas (P < 0.0001), especially in angiosarcomas, undifferentiated pleomorphic sarcomas, and leiomyosarcomas. Angiosarcomas were special in that MYC amplifications were particularly frequent and always high level, while other RIS showed low-level amplifications. We conclude that MYC amplifications are a frequent feature of RIS as a group and may contribute to the biology of these tumors.

Radiation-associated sarcoma of the skull base after irradiation for pituitary adenoma

Secondary, radiation-induced neoplasms represent a significant long-term risk after radiation treatment, and radiation-induced sarcomas (RAS) have an especially poor prognosis. These have rarely been reported after irradiation for pituitary adenomas.

[Radiation-induced sarcoma of the head and neck]

INTRODUCTION

Radiation-induced sarcoma (RIS) of the head and neck is a late and rare complication of cancer treatment by radiation therapy. It occurs mostly within the limits of the irradiated area. Its incidence is increasing and related to an improved survival rate of treated patients. But it does not rule out the use of radiotherapy in the treatment of this cancer.

OBSERVATION

We report two cases of sarcoma having appeared in the irradiated area, in patients treated by adjuvant radiotherapy for head and neck neoplasm.

DISCUSSION

The prognosis for this sarcoma depends mainly on how early the diagnosis is made and the quality of surgical resection. Adjuvant chemotherapy or radiotherapy can be considered. Ongoing research on the expression of RIS genes could soon lead to new treatments.

Low-grade myxofibrosarcoma presenting at the site of prior high-grade disease

Myxofibrosarcoma is one of the most common soft tissue sarcomas occurring in older adults. It can arise de novo or can be radiation induced, and the term myxofibrosarcoma was originally devised to encompass a spectrum of myxoid tumors with characteristics similar to malignant fibrous histiocytoma (MFH). Confusion exists, however, regarding the distinction between microscopic grade and characteristics of myxofibrosarcoma and MFH. Correct classification is vital to prognosis, as the degree of myxoid change is inversely related to the incidence of metastasis. We present a case of a 76-year-old man with a history of high-grade MFH of the left lower extremity, status post excision and radiation therapy, who presented 2 years later with a regional metastatic recurrence of high-grade MFH to the left groin as well as new nodules adjacent to and within his prior excision and radiation site. These new nodules were determined to represent low-grade myxofibrosarcoma. These new low-grade lesions either represent a low-grade recurrence of high-grade sarcoma or a new, radiation-induced soft tissue sarcoma occurring at the same site. Radiotherapy, however, is an unlikely cause; specific postradiation sarcoma criteria have not been fulfilled. This article discusses both the nosology and histopathological spectrum of these important soft tissue sarcomas, their aggressive and recurrent nature and their association with radiation therapy.

Malignant fibrous histiocytoma two years after autologous stem cell transplant for Hodgkin lymphoma: evidence for genomic instability

Secondary malignancies (SMs) in Hodgkin lymphoma (HL) are thought to be related to exposure to alkalating agents, topoisomerase II inhibitors and ionizing radiation, and tend to occur a decade after initial therapy. We report a 14 year old autistic male, who developed malignant fibrous histiocytoma (MFH) two years after autologous stem cell transplantation for advanced stage HL. The MFH and post-surgical reactive tissues exhibited multiple clonal abnormalities. In addition, PHA-stimulated peripheral blood lymphocytes showed increased frequency of non-clonal chromosomal aberrations. The potential role of genomic instability in early onset of SM in our patient is discussed.

Advances in the identification of molecular markers for bone neoplasia

IMPORTANCE OF THE FIELD

Bone tumors represent a heterogeneous and poorly understood group of neoplasms affecting patients of all ages. This review is intended to highlight recent advances in the identification of diagnostically relevant molecular biomarkers.

AREAS COVERED IN THIS REVIEW

This review offers a summary of basic techniques in molecular pathology. In the case of primary bone tumors with diagnostically applicable molecular markers, an overview of the tumor is provided incorporating the germane background and advances in the identification of molecular markers.

WHAT THE READER WILL GAIN

The reader will gain an understanding of the techniques governing the discovery of biomarkers, and their applicability in diagnostic bone pathology.

TAKE HOME MESSAGE

Molecular analysis has identified key diagnostic biomarkers in only a small proportion of bone tumors. Many of these findings owe their existence to earlier karyotype-based cytogenetic studies. In cases where characteristic cytogenetic findings are absent, there remains a tremendous need to interrogate rigorously these lesions using emerging techniques such as whole genome sequencing. It is assumed that with a more precise understanding of the tumor genetic code, more accurate diagnostic, prognostic and therapeutic markers will emerge.

Leiomyosarcoma of the larynx as a local relapse of squamous cell carcinoma--report of an unusual case

BACKGROUND

The authors report on leiomyosarcoma after previously treated squamous cell carcinoma (SCC) at the glottis.

METHODS

Primary tumor and relapses were investigated morphologically, immunohistochemically, and with molecular methods.

RESULTS

The SCC was typical, but few cells showed a spindle-shaped pattern. The relapse tumor was a spindle-shaped and epitheloid tumor with the morphological and immunohistochemical appearance of leiomyosarcoma (sm-actin+, desmin+, caldesmon+, vimentin+, keratin-).The comparative genomic hybridization (CGH) revealed some gains and losses in the leiomyosarcoma. Because of altered material, the investigation failed in the primary. A fluorescence in situ hybridization (5p) focally detected 3 chromosmomal copies, corresponding to gains on 5p in CGH of leiomyosarcoma.

CONCLUSION

Leiomyosarcoma after SCC is very uncommon. A connection between both seems likely in this case. Transdifferentiation, also seen in other tumors or carcinosarcomas, could be based on aberrant differentiation of a pluripotent stem cell.

Soft tissue sarcomas with complex genomic profiles

Soft tissue sarcomas (STS) with complex genomic profiles (50% of all STS) are predominantly composed of spindle cell/pleomorphic sarcomas, including leiomyosarcoma, myxofibrosarcoma, pleomorphic liposarcoma, pleomorphic rhabdomyosarcoma, malignant peripheral nerve sheath tumor, angiosarcoma, extraskeletal osteosarcoma, and spindle cell/pleomorphic unclassified sarcoma (previously called spindle cell/pleomorphic malignant fibrous histiocytoma). These neoplasms show, characteristically, gains and losses of numerous chromosomes or chromosome regions, as well as amplifications. Many of them share recurrent aberrations (e.g., gain of 5p13-p15) that seem to play a significant role in tumor progression and/or metastatic dissemination. In this paper, we review the cytogenetic, molecular genetic, and clinicopathologic characteristics of the most common STS displaying complex genomic profiles. Features of diagnostic or prognostic relevance will be discussed when needed.

Cytogenetic and molecular characterization of plutonium-induced rat osteosarcomas

The association between ionizing radiation and the subsequent development of osteosarcoma has been well described, but little is known about the cytogenetic and molecular events, which could be involved in the formation of radiation-induced osteosarcomas. Here, we performed comparative genomic hybridization (CGH) to detect chromosomal copy number changes in a series of 16 rat osteosarcomas induced by injection of plutonium-238. Recurrent gains/amplifications were observed at chromosomal regions 3p12-q12, 3q41-qter, 4q41-qter, 6q12-q16, 7q22-q34, 8q11-q23, 9q11-q22, 10q32.1-qter, and 12q, whereas recurrent losses were observed at 1p, 1q, 3q23-q35, 5q21-q33, 8q24-q31, 10q22-q25, 15p, 15q, and 18q. The gained region at 7q22-q34 was homologous to human chromosome bands 12q13-q15/8q24/22q11-q13, including the loci of Mdm2, Cdk4, c-Myc and Pdgf-b genes. The lost regions at 5q21-q33, 10q22-q25 and 15q contained tumor suppressor genes such as p16INK4a/p19ARF, Tp53 and Rb1. To identify potential target gene(s) for the chromosomal aberrations, we compared the expression levels of several candidate genes, located within the regions of frequent chromosomal aberrations, between the tumors and normal osteoblasts by using quantitative RT-PCR analysis. The Cdk4, c-Myc, Pdgf-b and p57KIP2 genes were thought to be possible target genes for the frequent chromosomal gain at 7q22-34 and loss at 1q in the tumors, respectively. In addition, mutations of the Tp53 gene were found in 27% (4 of 15) osteosarcomas. Our data may contribute to further understanding of the molecular mechanisms underlying osteosarcomas induced by ionizing radiation in human.

MYC high level gene amplification is a distinctive feature of angiosarcomas after irradiation or chronic lymphedema

Angiosarcomas (AS) are rare vascular malignancies that arise either de novo as primary tumors or secondary to irradiation or chronic lymphedema. The cytogenetics of angiosarcomas are poorly characterized. We applied array-comparative genomic hybridization as a screening method to identify recurrent alterations in 22 cases. Recurrent genetic alterations were identified only in secondary but not in primary AS. The most frequent recurrent alterations were high level amplifications on chromosome 8q24.21 (50%), followed by 10p12.33 (33%) and 5q35.3 (11%). Fluorescence in situ hybridization analysis in 28 primary and 33 secondary angiosarcomas (31 tumors secondary to irradiation, 2 tumors secondary to chronic lymphedema) confirmed high level amplification of MYC on chromosome 8q24.21 as a recurrent genetic alteration found exclusively in 55% of AS secondary to irradiation or chronic lymphedema, but not in primary AS. Amplification of MYC did not predispose to high grade morphology or increased cell turnover. In conclusion, despite their identical morphology, secondary AS are genetically different from primary AS and are characterized by a high frequency of high level amplifications of MYC. This finding may have implications both for the diagnosis and treatment of these tumors.

Does comparative genomic hybridization reveal distinct differences in DNA copy number sequence patterns between leiomyosarcoma and malignant fibrous histiocytoma?

Leiomyosarcoma (LMS) is the third most common type of soft tissue sarcoma after malignant fibrous histiocytoma (MFH) and liposarcoma. Comparative genomic hybridization (CGH) has shown similar DNA copy number imbalances in LMS and MFH. It has been suggested that both tumors may correspond to different differentiation states of a single tumor entity and that a large proportion of MFHs could correspond to undifferentiated LMS. We report CGH results from 102 MFH and 82 LMS cases, as well as a subsequent clustering analysis. The distribution pattern of DNA copy number changes could not differentiate LMS from MFH, suggesting that most MFHs could represent an ultimate state of tumor progression of LMS. Even if an oncogenic pattern common to LMS and MFH is valid, the genes relevant to smooth muscle cell differentiation may reside in one or more chromosomal imbalances that are not shared by both tumor types. Further explorative analysis identified a small cluster of tumors (9% of the samples: 2 LMS and 10 MFH) characterized by the presence of high-level amplifications at 1p33 approximately p34.3, 17q22 approximately q23, 17q25 approximately qter, 19p, 22p, and 22q, and associated with a higher proportion of tumors located in the thigh (P=0.003) and with male sex (P=0.079).

Sarcomas and sarcomatoid tumor after radiotherapy of oral squamous cell carcinoma: analysis of 4 cases

Radiation-induced sarcoma (RIS) or postirradiation sarcoma has been reported rarely as a long-term complication of radiation therapy (RT). We report 4 cases of oral sarcomas or sarcomatoid tumors with a rather short latency period after radiotherapy of the prior OSCC. Histopathological evaluation and immunohistochemical study were performed using a panel of markers including vimentin, cytokeratin, S-100, desmin, myoglobin, HHF-35, p53, and p16. All reported cases were positive for vimentin and negative for cytokeratin. Two cases were positive for myoglobin, desmin, or HHF-35, and were probably myogenic origin. One case was possibly a fibrosarcoma and the subclassification of the other one was not specified. Diverse expression of p53 and p16 was further observed in these 4 cases. Report of the complicated clinical processes and the analysis of genetic markers of these cases provide useful clinical and pathogenetic insights of mesenchymal malignancies associated with a status post OSCC radiation.

Radiation-induced sarcomas of bone: factors that affect outcome

We identified 42 patients who presented to our unit over a 27-year period with a secondary radiation-induced sarcoma of bone. We reviewed patient, tumour and treatment factors to identify those that affected outcome. The mean age of the patients at presentation was 45.6 years (10 to 84) and the mean latent interval between radiotherapy and diagnosis of the sarcoma was 17 years (4 to 50). The median dose of radiotherapy given was estimated at 50 Gy (mean 49; 20 to 66). There was no correlation between radiation dose and the time to development of a sarcoma. The pelvis was the most commonly affected site (14 patients (33%)). Breast cancer was the most common primary tumour (eight patients; 19%). Metastases were present at diagnosis of the sarcoma in nine patients (21.4%). Osteosarcoma was the most common diagnosis and occurred in 30 cases (71.4%). Treatment was by surgery and chemotherapy when indicated: 30 patients (71.4%) were treated with the intention to cure. The survival rate was 41% at five years for those treated with the intention to cure but in those treated palliatively the mean survival was only 8.8 months (2 to 22), and all had died by two years. The only factor found to be significant for survival was the ability to completely resect the tumour. Limb sarcomas had a better prognosis (66% survival at five years) than central ones (12% survival at five years) (p = 0.009). Radiation-induced sarcoma is a rare complication of radiotherapy. Both surgical and oncological treatment is likely to be compromised by the treatment received previously by the patient.

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

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

Local recurrence of myxofibrosarcoma is associated with increase in tumour grade and cytogenetic aberrations, suggesting a multistep tumour progression model

Myxofibrosarcoma is one of the most frequent soft tissue tumours in elderly patients, mostly arising in the extremities. Grade I lesions are only locally aggressive whereas grade II and grade III lesions have metastatic potential. The differential diagnosis contains several other (benign) myxoid soft tissue tumours. A number of sarcomas are characterised by specific cytogenetic aberrations, giving not only insight in their biological pathways; they also serve as molecular markers in difficult diagnoses. Cytogenetic data on myxofibrosarcoma are scarce with only few isolated cases described in the literature. No specific chromosomal aberrations have been detected so far. Moreover, molecular pathways in tumorigenesis and progression of myxofibrosarcoma are barely understood. We studied the clinicopathologic data and karyotypes of 32 myxofibrosarcomas using conventional banding and multicolour COmbined Binary RAtio labelling fluorescence in situ hybridisation technique. We included eight grade I, eight grade II and 16 grade III lesions. In all, 22 were primary tumours, nine were local recurrences and one a lymph node metastasis. The myxofibrosarcomas showed equal sex distribution, were mostly located at the extremities with two thirds deep-seated and had an average age of occurrence of 66 years. We found normal karyotypes in eight cases and clonal beside nonclonal aberrations in 22 cases. Complex cytogenetic anomalies were found in all grades. However, no tumour-specific chromosomal abnormalities could be withdrawn. Local recurrences showed increase in grade compared to their primary lesions. Interestingly, these recurrences showed more complex cytogenetic aberrations. Increase in grade seems to parallel increase in cytogenetic aberrations and malignant potential. Since the chromosomal aberrations found were not tumour type specific, they seem to be rather the result of secondary events in tumour progression and tumour genetic instability. Based on these findings, we suggest that tumorigenesis of myxofibrosarcoma is mainly a multistep genetic process, probably ruled by genetic instability caused by targeted checkpoint genes.

High-resolution cDNA microarray CGH mapping of genomic imbalances in osteosarcoma using formalin-fixed paraffin-embedded tissue

Formalin-fixed paraffin embedded (FFPE) tumor tissue provides an opportunity to perform retrospective genomic studies of tumors in which chromosomal imbalances are strongly associated with oncogenesis. The application of comparative genomic hybridization (CGH) has led to the rapid accumulation of cytogenetic information on osteosarcoma (OS); however, the limited resolving power of metaphase CGH does not permit precise mapping of imbalances. Array CGH allows quantitative detection and more precise delineation of copy number aberrations in tumors. Unfortunately the high cost and lower density of BACs on available commercial arrays has limited the ability to comprehensively profile copy number changes in tumors such as OS that are recurrently subject to genomic imbalance. In this study a cDNA/EST microarray including 18,980 human cDNAs (which represent all 22 pairs of autosomal chromosomes and chromosome X) was used for CGH analysis of eight OS FFPE. Chromosomes 1, 12, 17, and X harbored the most imbalances. Gain/amplification of X was observed in 4/8 OS, and in keeping with other recent genomic analyses of OS, gain/amplification of 17p11.2 was often accompanied by a distal deletion in the region of the p53 gene. Gain/amplification of the X chromosome was verified using interphase FISH carried out on a subset of OS FFPE sections and OS tissue arrays.

Amplification of chromosome 1 sequences in lipomatous tumors and other sarcomas

Amplifications and gains involving 1q are common abnormalities in solid tumors. Recently, an amplicon originating from 1q21-23, containing the candidate oncogenes COAS1, COAS2 and COAS3 (Chromosome One Amplified Sequence) was identified. The presence, distribution and copy number level of extra COAS sequences were investigated in 48 bone and soft tissue tumor (BSTT) samples using metaphase FISH analysis. Amplification was seen in 27/48 (56%) samples. With few exceptions, all 3 genes were involved, but on average COAS2 exhibited higher copy numbers. The presence of extra COAS signals, irrespective of copy numbers, was found at similar frequencies in different histologic tumor subtypes. However, medium or high level amplification was common in lipomatous tumors but rare in other, nonlipomatous tumors (9/21 vs. 2/27 samples). The most common localization of extra COAS signals in lipomatous tumors was in supernumerary ring and giant marker chromosomes. Among nonlipomatous tumors, the distribution of extra COAS genes was more disperse, being located in various unidentified chromosomal structures, including double minutes, and only rarely in ring chromosomes. Because MDM2 is known to be amplified frequently in BSTTs, and in particular in atypical lipomatous tumors, cases with extra copies of COAS were studied also with an MDM2 probe. Twelve out of 18 lipomatous tumors had extra copies of both COAS and MDM2, and the 2 genes were found to be coamplified and interspersed exclusively in ring and giant marker chromosomes. Also 12 out of 18 nonlipomatous tumors exhibited simultaneous gain of COAS and MDM2, but colocalization in the same chromosome was less frequent. The role of the frequent coamplification of COAS, or some other yet unknown gene in the 1q21-23 region, and MDM2 remains to be elucidated.

Second cancers after radiotherapy: any evidence for radiation-induced genomic instability?

Do second primary cancers in humans arise from radiation-induced somatic genomic instability after radiotherapy for the first malignancy? The amount of truly pertinent human information on this issue is sparse, leading to the conclusion that we cannot confirm or refute that instability induction by radiation is involved. However, the in vitro findings of radiation-induced genomic instability through bystander effects or increased mutation rates in cell progeny of apparently normal but irradiated cells are provocative and their transferability to human in vivo biology deserves further investigation. We describe possible animal and human studies to stimulate ideas, but the collaborative commitment of multiple large institutions to tumor tissue procurement and retrieval will be essential. In addition, detecting the temporal progression of genomic instability and identifying the salient genetic events as being radiation-induced will be pivotal. Execution of some of the studies suggested is not possible now, but applying next-generation methods could bring the concepts to fruition. As nearly one in 10 cancer diagnoses are second (or higher) malignancies, it is important to understand the contribution of radiotherapy to second cancer induction and pursue well-coordinated efforts to determine the role of induced genomic instability.

High-resolution mapping of amplifications and deletions in pediatric osteosarcoma by use of CGH analysis of cDNA microarrays

Conventional cytogenetic and comparative genomic hybridization (CGH) studies have shown that osteosarcomas (OSs) are characterized by complex structural and numerical chromosomal alterations and gene amplification. In this study, we used high-resolution CGH to investigate recurrent patterns of genomic imbalance by use of DNA derived from nine OS tumors hybridized to a 19,200-clone cDNA microarray. In six OSs, there was copy number gain or amplification of 6p, with a minimal region of gain centering on segment 6p12.1. In seven OSs, the pattern of amplification affecting chromosome arm 8q showed high-level gains of 8q12-21.3 and 8q22-q23, with amplification of the MYC oncogene at 8q24.2. Seven OSs showed copy number gain or amplification of 17p between the loci bounded by GAS7 and PMI (17p11.2-17p12), and three of these tumors also showed small losses at 17p13, including the region containing TP53. An in silico analysis of the distribution of segmental duplications (duplicons) in this region identified a large number of tracts consisting of paralogous sequences mapping to the 17p region, encompassing the region of deletions and amplifications in OS. Interestingly, within this same region there were clusters of duplicons and several genes that are expressed during bone morphogenesis and in OS. In summary, microarray CGH analysis of the chromosomal imbalances of OS confirm the overall pattern observed by use of metaphase CGH and provides a more precise refinement of the boundaries of genomic gains and losses that characterize this tumor.

Spectral karyotyping identifies recurrent complex rearrangements of chromosomes 8, 17, and 20 in osteosarcomas

Conventional cytogenetic studies have shown that osteosarcomas (OSs) are often highly aneuploid, with a large number of both structural and numerical chromosomal alterations. To investigate the complexity of OS karyotypes in detail, we applied spectral karyotyping (SKY) to a series of 14 primary OS tumors and four established OS cell lines. A total of 531 rearrangements were identified by SKY, of which 300 breakpoints could be assigned to a specific chromosome band. There was an average of 38.5 breakpoints identified by SKY per primary tumor. Chromosome 20 was involved in a disproportionately high number of structural rearrangements, with 38 different aberrations being detected. Chromosomal rearrangements between chromosomes 20 and 8 were evident in four tumors. FISH analysis using a 20q13 subtelomeric probe identified frequent involvement of 20q in complex structural rearrangements of OS cell lines. Characterization of the structural aberrations of chromosomes 8 and 17 by use of SKY demonstrated frequent duplication or partial gains of chromosome bands 8q23-24 and 17p11-13. Other chromosomes frequently involved in structural alteration were chromosomes 1 (47 rearrangements) and 6 (38 rearrangements). Centromeric rearrangements often involving chromosomes 1, 6, 13, 14, 17, and 20 were present. Four of the 14 primary OS tumors were characterized by nonclonal changes that included both structural and numerical alterations. In summary, OS tumors have a very high frequency of structural and numerical alterations, compounded by gross changes in ploidy. This intrinsic karyotype instability leads to a diversity of rearrangements and the acquisition of composite chromosomal rearrangements, with the highest frequency of alteration leading to gain of 8q23-24 and 17p11-13 and rearrangement of 20q. These findings suggest that specific sequences mapping to these chromosomal regions will likely have a role in the development and progression of OS.

Gains of 12q are the most frequent genomic imbalances in adult fibrosarcoma and are correlated with a poor outcome

Comparative genomic hybridization was used to analyze 41 adult fibrosarcomas from 34 patients. Thirty-one patients showed in their tumors DNA sequence copy number changes (mean 11, range 3-25). The minimal common regions for the most frequent gains were narrowed down to 12q21 (18 cases); 12q14-q15 and 14q22 (16 cases each); 4q22, 7q31, and 14q23-q24 (15 cases each); and 4q21, 4q23-q24, 8q22, and 12q22 (14 cases each). Twenty-five high-level amplifications were observed in 12 samples. 12q21 and 18p were affected three times each; and 1p21, 4q31.3, 7p21, 12q14-q15, Xp22.1-p22.2, and Xq22-q23 two times each. Losses were less frequent than gains. Early stages of adult fibrosarcomas were characterized by frequent gains of chromosomes 2, 4q, and 14q, whereas gains of chromosomes 7 and 8q were associated with progression. Gains of 12q were frequent in all of the developmental steps of this soft-tissue sarcoma. By investigation of several tumors of the same patient, a number of corresponding changes were always detected. Adult fibrosarcomas from patients who died during the observation time showed statistically significant more frequent gains of 8q, 12q, 13q, and 15q compared to the fibrosarcomas of patients who are alive. Gains and high-level amplifications of 12q14-q22, which were the most frequent genomic imbalances, partly reflected an MDM2 amplification, indicating the importance of this region in the tumorigenesis of sarcomas. In adult fibrosarcomas, a gain of 12q22 correlated significantly (P = 0.028) with a poor overall survival rate.

Compilation of published comparative genomic hybridization studies

The power of comparative genomic hybridization (CGH) has been clearly proven since the first paper appeared in 1992 as a tool to characterize chromosomal imbalances in neoplasias. This review summarizes the chromosomal imbalances detected by CGH in solid tumors and in hemopathies. In May of 2001, we took a census of 430 articles providing information on 11,984 cases of human solid tumors or hematologic malignancies. Comparative generic hybridization has detected a number of recurrent regions of amplification or deletion that allows for identification of new chromosomal loci (oncogenes, tumor suppressor genes, or other genes) involved in the development, progression, and clonal evolution of tumors. When CGH data from different studies are combined, a pattern of nonrandom genetic aberrations appears. As expected, some of these gains and losses are common to different types of pathologies, while others are more tumor-specific.

Genome instability in secondary solid tumors developing after radiotherapy of bilateral retinoblastoma

Genome alterations of seven secondary tumors (five osteosarcomas, one malignant peripheral sheath nerve tumor, one leiomyosarcoma) occurring in the field of irradiation of patients treated for bilateral retinoblastoma have been studied. These patients were predisposed to develop radiation-induced tumors because of the presence of a germ line mutation in the retinoblastoma gene (RB1). Tumor cells were characterized by a high chromosome instability whereas microsatellites and minisatellites were found to be stable. In all tumors, the normal RB1 allele was lost with the corresponding chromosome 13, whereas the germ line mutated allele was retained. The two alleles of TP53 were inactivated, one by deletion of the short arm of chromosome 17, the other by mutation. As compared with non-radiation-induced tumors, the observed panel of TP53 mutations was uncommon with sites not recurrently found otherwise and a high rate of deletions (3/7). In these predisposed patients, the loss of the single normal allele of RB1 is rather due to the radiation-induced chromosome instability than a direct effect of ionizing radiation.

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 analysis identifies gains of 1p35 approximately p36 and chromosome 19 in osteosarcoma

Osteosarcomas (OS) are aggressive tumors of the bone and often have a poor prognosis. Conventional cytogenetic analyses of OS have revealed highly complex karyotypes, with numerous abnormalities. In this study, we analyzed 18 untreated OS tumors from 17 patients of the younger incidence age group by comparative genomic hybridization (CGH), 4 tumors by spectral karyotyping (SKY) and fluorescence in situ hybridization (FISH). Comparative genomic hybridization identified frequent copy number changes of the chromosomal region 1p (10/17) and gain of part or all of chromosome 19(8/17). In addition gains were observed at 5p(3/17), 8q(3/17), 16p(3/17), and 17p(5/17); and losses at chromosomes 2q(3/17), 10(4/17) and 13(3/17). High level gains were detected in the 8q23 approximately q24 region in two tumors as well as at 17p in one primary and a metastatic tumor. Minimal regions of gain were present at 1p35 approximately p36.3 (8/17); 5p14 approximately p15.2 (3/17), and 8q22 approximately q24.3 (3/17). SKY analysis demonstrated that OS has a complex pattern of clonal and non-clonal rearrangements and helped confirm the structural basis for the imbalances detected by CGH. Spectral karyotyping confirmed an overall pattern of chromosomal gain affecting 1p in all four tumors. Fluorescence in situ hybridization analysis from these tumors confirmed the gain of the 1p36 region in 2 tumors as determined by CGH analysis as well as the amplification of 8q.

Cytogenetic study of six cases of radiation-induced meningiomas

It is known that, following radiotherapy, secondary cancer may occur after a long latent period. Few cytogenetic studies have been reported on tumors of the central nervous system occurring after radiotherapy. We report the cytogenetic study of six cases of radiation-induced meningiomas. In all cases, we observed the same chromosome abnormality, der(1)(1qter-->1p11::22q12-->22pter). SKY and CGH techniques allowed us to identify the chromosomal abnormalities. We suggest that a gene localized on 1p13 is involved in radiation-induced meningiomas.

A novel reciprocal (10;17)(p11.2;q23) in myxoid fibrosarcoma

Recurring reciprocal translocations have been identified as the primary chromosome aberrations in a number of neoplasms. These aberrations are often closely associated with particular morphologic or phenotypic subtypes of tumors and in some cases have prognostic implications. We have identified a novel reciprocal t(10;17)(p11.2;q23) in a case of low-grade myxoid fibrosarcoma, which may prove to be a new tumor specific chromosome aberration.