The utility of FISH analysis in the diagnosis of BCOR-rearranged sarcomas

BACKGROUND

A BCL6 corepressor (BCOR) gene alteration is a genetic signature of rare subsets of sarcomas. The identification of this alteration has recently contributed to the definition of new entities in the current WHO (2020) classification of soft tissue and bone tumours. We retrospectively examined cases of BCOR-rearranged sarcoma (BRS) to assess the reliability of the BCOR FISH analysis using an IVD (in vitro diagnostic) probe.

METHODS

We investigated and compared the molecular diagnostic strategies and features by collecting 17 data from patients with a BCOR gene rearrangement detected using quantitative-Reverse Transcription-Polymerase Chain Reaction (qRTPCR), Next-Generation Sequencing (NGS) and Fluorescence in situ hybridization (FISH).

RESULTS

We describe fourteen BCOR::CCNB3 sarcomas, one spindle cell sarcoma with a novel BCOR::MAML1 fusion, one spindle cell sarcoma with a novel BCOR::AHR fusion, and one ossifying fibromyxoid tumour with a BCOR::ZC3H7B fusion. FISH analysis of all, except one, BCOR::CCNB3 sarcoma, showed a FISH break-apart pattern with mild signal separation. The MAML1::BCOR sarcoma showed large-space split signals, while in the two patients with AHR::BCOR and ZC3H7B::BCOR fusions, no BCOR rearrangement was observed using FISH.

CONCLUSIONS

Our study indicates that BCOR FISH analysis using an IVD probe, may be useful to detect the presence of a BCOR rearrangement, including both translocations and inversions; however, negative results, in some cases, can occur.

IDH mutations in G2-3 conventional central bone chondrosarcoma: a mono institutional experience

BACKGROUND

Heterozygous isocitrate dehydrogenase (IDH) mutations occur in about half of conventional central bone chondrosarcomas (CCBC). Aim of this study was to assess the frequency and prognostic impact of IDH mutations in high grade CCBC patients.

METHODS

64 patients with G2 and G3 CCBC were included. DNA extraction, PCR amplification of IDH1/2 exon 4s, and sequencing analysis with Sanger were performed.

RESULTS

IDH mutations were detected in 24/54 patients (44%): IDH1 in 18, IDH2 in 4, and both IDH1/2 in 2 patients. The frequency of mutations was 37% in G2 vs. 69% in G3 (p = 0.039), and 100% in three Ollier disease associated chondrosarcoma. 5-year overall survival (OS) at 124 months (range 1-166) was 51%, with no significant difference based on the IDH mutational status: 61% in IDHmut vs. 44% in IDH wild type (IDHwt). The 5-year relapse free survival (RFS) was 33% (95% CI:10-57) for IDHmut vs. 57% (95%CI: 30-77) for IDHwt. Progression free survival (PFS) was 25% (95%CI:1-65) IDHmut vs. 16% (95%CI: 0.7-52) IDHwt. 55% (5/9) of IDHmut G2 became higher grade at the recurrence, as compared with 25% (3/12) of G2 IDHwt.

CONCLUSIONS

This study shows a higher frequency of IDH mutations in G3 CCBC as compared with G2. No significant differences in OS, RFS, and PFS by mutational status were detected. After relapse, a higher rate of G3 for IDH mutated CCBC was observed.

The Efficacy of Molecular Analysis in the Diagnosis of Bone and Soft Tissue Sarcoma: A 15-Year Mono-Institutional Study

The histological diagnosis of sarcoma can be difficult as it sometimes requires the combination of morphological and immunophenotypic analyses with molecular tests. A total of 2705 tissue samples of sarcoma consecutively collected from 2006 until 2020 that had undergone molecular analysis were assessed to evaluate their diagnostic utility compared with histological assessments. A total of 3051 molecular analyses were performed, including 1484 gene fusions tested by c/qRT-PCR, 992 gene rearrangements analysed by FISH, 433 analyses of the gene status of MDM2, 126 mutational analyses and 16 NGS analysis. Of the samples analysed, 68% were from formalin-fixed, paraffin-embedded tissue and 32% were from frozen tissue. C/qRT-PCR and FISH analyses were conclusive on formalin-fixed, paraffin-embedded tissue in 74% and 76% of samples, respectively, but the combination of the two methods gave us conclusive results in 96% and 89% of frozen and formalin-fixed, paraffin-embedded tissues, respectively. We demonstrate the utility of c/qRT-PCR and FISH for sarcoma diagnosis and that each has advantages in specific contexts. We conclude that it is possible to accurately predict the sarcoma subtype using a panel of different subtype-specific FISH probes and c/qRT-PCR assays, thereby greatly facilitating the differential diagnosis of these tumours.

Primary synovial sarcoma of bone: A retrospective analysis of 25 patients

AIMS

To evaluate diagnostic accuracy of SSX and SSX-SS18 antibodies in decalcified surgical specimens and outcome of synovial sarcomas (SS) of bone.

METHODS AND RESULTS

Twenty-five cases were classified as bone SS (prevalence 0.32% among malignant primary bone sarcoma). Median age was 34 years (range 9 -79) . 24/25 patients presented with non-metastatic tumors, one with lung metastases. The majority of tumors involved the long bones of extremities with metaphyseal origin. Mean size of the tumor was 7.1 cm. 20 cases (80%) were monophasic and 5 (20%) biphasic. SS18-SSX fusion-specific antibody had 92% sensitivity and 99% specificity for primary bone SS, whereas SSX C-terminus antibody had 100% sensitivity and 94% specificity. FISH analysis was feasible in 9 (36%) cases and detected SS18 rearrangement in all 9 cases. All patients underwent surgical removal of their primary tumor, with adequate margins in 18 (72%) patients. Chemotherapy with metothrexate, cisplatin, doxorubicin, ifosfamide was used in the 7 patients. Two patients with inadequate surgical margins received radiotherapy. With a median follow-up of 80 months (range 6-428), 5-year and 10-year overall survival (OS) were 66.6% and 47.9% respectively and 5-and 10-years disease-free survival (DFS) were 36.8% (95% C.I.: 18.0-55.7%), and 32.2% (95% C.I.: 14.6-51.2%) respectively A significant improvement in 10-years DFS in patients undergoing chemotherapy as compared with patients who did not was observed (p 0.039).

CONCLUSIONS

Our series highlights the utility of SS18-SSX fusion-specific and SSX C-terminus antibodies to support the diagnosis of SS, Adjustment chemotherapy was associated with improved prognosis in this series.

Abstract 5909: IDH mutations in G2-3 conventional chondrosarcoma of bone: a mono institutional experience

Purpose: 5-years overall survival (OS) in high grade conventional chondrosarcoma is about 50%. Grade has been identified as the main prognostic factor. Heterozigous isocitrate dehydrogenase (IDH) mutations are present in about half of conventional chondrosarcomas, with higher frequency in low grade lesions. IDH prognostic role is not fully understood. Aim of this study is to assess the frequency of IDH mutations in high grade chondrosarcoma, their relationship with clinical characteristics, and their prognostic role. Methods: patients who underwent surgery at Rizzoli between 2002 and 2012 with a diagnosis of G2- G3 conventional chondrosarcoma and fresh frozen tissue available were selected from archives. DNA extraction was performed with commercial kit. PCR amplification of exon 4 of IDH1 and IDH2 genes, and sequencing analysis with Sanger was performed. Results: 54 patients identified:18 (33%) were male, 36 (67%) female; median age was 62 (range 17-85 years). 40 (74%) patients had localized tumor, and 14 (26%) presented with metastases. Tumor was in the extremities in 25 (46%) patients. 41 (76%) of the cases were G2, 13 (24%) G3. 4 patients had a genetic predisposition (1 Maffucci syndrome and 3 Ollier disease). IDH mutation was detected in 26 (48%) of the patients (20 IDH1, 4 IDH2, and 2 patients both IDH1 and 2). Frequency of mutation was 17 (65%) in G2, and 9 (35%) in G3. 4/4 chondrosarcomas in with a syndrome presented a mutation. Gender, site and stage were not significantly different by mutational status. After a median follow-up of 124 months (range 1-166) the 5-year OS was 51% (95% CI:36-64), with no difference according to mutational status (5-year OS IDHmut 54% vs IDHwt 48%, p=0.45), and better survival for localized vs metastatic pts (68% vs 7%, p<0.001), and for grade G2 vs G3 (59% vs 22%, p=0.0031). No difference in survival was observed for gender and site. In 25/27 patients with histological confirmation of recurrence/progression (21 cases G2, 4 G3), 27% of G2, IDHwt chondrosarcomas at initial diagnosis acquired higher grade in the recurrence, as compared with 50% in G2 IDHmut tumors. Conclusions: IDH mutations had higher frequency in G2 chondrosarcomas as compared to G3. No difference in OS according to mutational status was demonstrated. IDH mutated tumors had higher rate of grade progression at relapse, as compared to IDHwt. Confirmation of our results is needed in a larger series.

Citation Format: Elisabetta Setola, Stefania Benini, Alberto Righi, Gabriella Gamberi, Sofia Avnet, Elisa Carretta, Cristina Ferrari, Emanuela Palmerini, Pier Luigi Lollini, Marilena Cesari, Anna Paioli, Alessandra Longhi, Davide Maria Donati, Nicola Baldini. IDH mutations in G2-3 conventional chondrosarcoma of bone: a mono institutional experience [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5909.

Identification of a novel fusion transcript EWSR1-VEZF1 by anchored multiplex PCR in malignant peripheral nerve sheath tumor

The aim of the study is to describe a novel genetic finding examining the molecular and pathological features of a case of malignant peripheral nerve sheath tumor occurring in the thigh of a 17-year-old male. Fusion gene detection using a next-generation sequencing-based anchored multiplex PCR technique (Archer FusionPlex Sarcoma Panel) was used to identify the novel fusion of EWSR1-VEZF1 from the frozen tumor sample. EWSR1-VEZF1 fusion is a novel molecular gene rearrangement involving exon 8 of the EWSR1 gene and exon 2 of the VEZF1 gene. Data were validated with gene sequencing and fluorescent in situ hybridization (FISH) analysis. This case report describes a novel rearrangement involving EWSR1 on chromosome 22 and VEZF1 on chromosome 17. The result obtained demonstrates the value of the next-generation sequencing-based anchored multiplex PCR technique (Archer FusionPlex Sarcoma Panel) both in diagnosis and patient care and might become a helpful diagnostic tool for this tumor type.

Increased C-MYC Oncogene Expression in Ewing's Sarcoma: Correlation with Ki67 Proliferation Index

Aims and Background

Ewing's sarcoma is a highly malignant musculoskeletal tumor composed of small round cells. Although important results have been achieved with surgery associated with chemotherapy, recurrent disease is still a major problem. In order to define new prognostic factors useful for therapeutic decision-making, we conducted a study on 38 Ewing's sarcoma samples in which c-myc oncogene expression and Ki67 proliferation index were correlated with clinical outcome.

Methods and Study Design

Nineteen patients developed metastases during follow-up and 10 of these patients died. C-myc and Ki67 protein expression was evaluated by immunohistochemistry performed on 5 μm formalin-fixed and paraffin-embedded sections, while the c-myc mRNA transcript was localized using in situ hybridization.

Results

A statistically positive correlation was found between c-myc protein and Ki67 (P = 0.001) and c-myc mRNA and Ki67 expression (P = 0.047). The 38 patients were divided into two groups using as the cutoff 50% of Ki67-positive cells. The disease-free survival and overall survival estimates were 68% and 90%, respectively, in the group of patients with a percentage of Ki67-positive cells <50%, and 25% and 50%, respectively, in the group with a percentage of Ki67-positive cells ≥50%. The difference between the survival curves was statistically significant (P <0.05 and P <0.01). Furthermore, relapsed patients had a high and uniform expression of c-myc protein and mRNA compared to disease-free patients.

Conclusion

These results suggest a possible role of the c-myc oncogene and Ki67 antigen in the malignant progression of Ewing's sarcoma.

Detection of circulating tumor cells in liquid biopsy from Ewing sarcoma patients

Background

Circulating tumor cells (CTCs) analysis is a promising new diagnostic field to estimate risk and monitor treatment efficacy, metastatic relapse, and progression in cancer patients. The study aim was to isolate and characterize CTCs in blood samples of Ewing sarcoma (ES) patients exploiting two main characteristics: CD99 expression and presence of chromosomal translocations.

Materials and methods

The method isolated CTCs from peripheral blood (PB) of ES patients. Cell-surface CD99 was a useful marker for CTCs determined using immunomagnetic separation with microbeads and CD99 monoclonal antibody. We tested sensitivity and specificity by detecting CTCs in blood collected from healthy donors and randomly during therapy from 18 ES patients. Evidence of CTCs was confirmed by detection of specific molecular markers using quantitative and digital reverse transcription-polymerase chain reaction targeting EWSR1/FLI1 type 1 and type 2 or EWSR1/ETS-related gene transcripts type 1 and type 9e.

Results

Feasibility of finding CTCs in PB of ES patients by immunoseparation with CD99 antibody and magnetic microbeads was demonstrated for the first time. At molecular analysis, three PB specimens tested positive for chimeric EWSR1/FLI1 type 2 and one PB for chimeric EWSR1/FLI1 type 2. CTCs detection was found above a limit of detection of 1 cell/mL of PB.

Conclusion

CTCs in PB of ES patients can be identified by this method and in ES CTCs analysis can be used as a liquid biopsy approach for prognostic and predictive purposes. The potential clinical implications of CTCs in PB samples detected by the platform for CTC isolation with molecular confirmation during therapy require further evaluation.

Detection of H3F3A p.G35W and p.G35R in giant cell tumor of bone by Allele Specific Locked Nucleic Acid quantitative PCR (ASLNAqPCR)

Giant Cell Tumor (GCT) represents about 20% of benign bone tumors, is locally aggressive although malignant transformation is extremely rare, <1% of cases but 2-3% give pulmonary metastasis. Age at onset is between 20 and 40 years with a slight predominance for the female gender. GCT is characterized by specific mutations in H3F3A gene encoding the protein histone 3.3. The study of these mutations is important for the differential diagnosis with giant cell rich sarcomas, chondroblastoma and aneurysmal bone cyst. To identify the most frequent H3F3A mutations we developed a novel allele specific Real Time Polymerase Chain Reaction method, based on Allele Specific Locked Nucleic Acid (ASLNAqPCR) that is here described. Molecular analyses were performed on 20 GCT and 2 osteosarcoma arising on a previous GCT. All cases were verified by Sanger sequencing. We demonstrated that ASLNAqPCR is a quick, sensitive and reliable method to identify mutations of the H3F3A gene, in giant cell tumor of bone, to support diagnosis in morphologically ambiguous cases.

Histone 3.3 mutations in giant cell tumor and giant cell-rich sarcomas of bone

Mutually exclusive histone 3.3 gene mutations have been recognized in chondroblastoma and giant cell tumor of bone (GCTB), which may be useful for differential diagnostic purposes in morphologically ambiguous cases. Although more than 90% of GCTBs present histone 3.3 variants exclusively in the H3F3A gene, chondroblastoma is mutated mainly in H3F3B. In this study, we examined a series of giant cell-rich primary bone tumors, aiming to evaluate the possible diagnostic role of histone 3.3 mutations in the differential diagnosis between GCTB and giant cell-rich sarcomas. Sixteen cases of nonmetastatic GCTB, 9 GCTBs with lung metastases, and 35 giant cell-rich sarcomas were selected from our institutional archives. Eight chondroblastomas were used as controls. Direct sequencing for the presence of H3F3A and H3F3B variants in coding region between codons 1 and 42, including the hotspot codons (28, 35, and 37), was performed on DNA extracted from formalin-fixed, paraffin-embedded tissue using conventional polymerase chain reaction and fast coamplification at lower denaturation temperature-polymerase chain reaction. Overall, 24 GCTBs (96%) presented a mutation in the H3F3A gene (15 of 16 nonmetastatic and 9 of 9 metastatic). Five sarcomas harbored an H3F3A mutation (3 p.G35W, 1 p.G35L, and 1 p.G35E), and these were all secondary malignant GCTBs. In conclusion, we confirm that H3F3A mutational testing may be a useful adjunct to differentiate GCTB from giant cell-rich sarcomas. Although the presence of H3F3A mutations does not exclude with certainty a diagnosis of sarcoma, the possibility of a malignant evolution of GCTB should also be considered.

CIC-DUX4 fusion-positive round-cell sarcomas of soft tissue and bone: a single-institution morphological and molecular analysis of seven cases

AIMS

Round-cell sarcomas lacking specific translocations represent a diagnostic challenge. The aim of this study was to describe seven cases of CIC-DUX4 fusion-positive sarcomas, including the first reported example arising primarily in bone.

METHODS AND RESULTS

Patients ranged in age from 15 years to 44 years (median: 33 years). Six cases arose from the soft tissues, and one from the iliac bone. Morphologically, all cases showed an undifferentiated round-cell population with greater atypia and pleomorphism than Ewing sarcoma. Immunohistochemically, all tumours showed focal and weak positivity for CD99, and five of seven showed nuclear and/or cytoplasmic positivity for Wilms tumour 1. Five patients had lung metastases at presentation. All patients received chemotherapy according to Ewing sarcoma protocols. All but one patient (the one with a bone tumour) died of disease after a mean of 14.5 months from the diagnosis (range: 8-20 months).

CONCLUSIONS

Our series confirms that CIC-DUX4 fusion-positive sarcomas are aggressive tumours with an adverse prognosis, and with clinical, histological and genetic differences from Ewing sarcoma. The best therapeutic approach needs to be investigated.

Prognostic and predictive role of CXCR4, IGF-1R and Ezrin expression in localized synovial sarcoma: is chemotaxis important to tumor response?

Background

Synovial sarcoma (SS) is a rare tumor, with dismal survival when metastatic. The role of adjuvant chemotherapy is debated. New prognostic and predictive factors are needed.

Methods

We reviewed patients with localized SS; SS18-SSX fusion transcript presence was confirmed by FISH and RT-PCR. Expression of CXCR4, IGF-1R and Ezrin were evaluated by immunohistochemistry.

Results

Tumor samples from 88 SS patients (45 female; 43 male) with median age 37 years (range 11–63) were selected. The size of the lesion was > 5 cm in 68% of patients and 34% of cases presented biphasic histotype. All patients underwent surgery, 56% adjuvant radiotherapy (RT), 65% adjuvant chemotherapy. A positive stain for IGF-1R was detected in 55 patients, with nucleus expression in 21 patients. CXCR4 was expressed in 74 patients, nuclear pattern in 31 patients. 80 SS were positive to Ezrin, 48 had cytoplasmatic location, 32 membrane location. With a median follow-up of 6 years (1–30 years), the 5-year overall survival (OS) was 70% (95% CI 60–81). 5-year OS was 63% (95% CI 41-85%) for patients with positive IGF-1R/nuclear expression, and 73% (95% CI 61-85%; P = 0.05) in negative patients. 5-year OS was 47% (95% CI 27-66%) in patients with positive CXCR4/nuclear staining, and 86% (95% CI 76-96%, P = 0.0003) in negative cases. No survival difference was found according to Ezrin expression. By multivariate analysis, nuclear expression of CXCR4 and IGF-1R was confirmed independent adverse prognostic factor for SS patient survival linked to the use of chemotherapy.

Conclusions

Our findings have important potential implications demonstrating that together with clinical prognostic factors such as radiotherapy and age, CXCR4 and IGF-1R negatively influences survival in patients with localized SS. We believe that further studies addressed to the effects of CXCR4 and IGF-1R inhibitors on cell viability and function are needed to plan new and more appropriate SS treatments.

MDM2 and CDK4 expression in periosteal osteosarcoma

Periosteal osteosarcoma is defined by the World Health Organization as an intermediate-grade, malignant, cartilaginous, and bone-forming neoplasm arising on the surface of bone. Unlike other subtypes of osteosarcoma, no data have been published about mouse double minute 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) expression. For this reason, we evaluated the molecular and immunohistochemical features of MDM2 and CDK4 in 27 cases relative to 20 patients with a diagnosis of periosteal osteosarcoma, surgically treated at the Rizzoli Institute between 1981 and 2014. When possible, these results were compared with the MDM2 amplification status as determined by fluorescence in situ hybridization (FISH). All but 1 case (26/27, 96.3%) were negative for MDM2 protein using immunohistochemistry both in primary and in recurrent periosteal osteosarcoma, whereas gene amplification of MDM2 was not detected in any tumor analyzed (10 cases). The positive immunohistochemical case shows a weak/moderate focal nuclear expression of MDM2 antibody in the prevalent cartilaginous component and in the spindle cells of peripheral fibroblastic areas associated with osteoid production in a primary periosteal osteosarcoma. CDK4 immunohistochemical expression was negative in all 27 cases. This retrospective analysis has demonstrated that MDM2 and CDK4 are very rarely expressed in primary and recurrent periosteal osteosarcomas and therefore do not appear to be molecules central to the control of cancer development, growth, and progression in periosteal osteosarcoma. Therefore, when compared with low-grade central and parosteal osteosarcomas, MDM2 and CDK4 markers cannot be used diagnostically to differentiate this subtype of osteosarcoma.

Synovial sarcoma: Is chemotaxis important to tumor progression?

10571

Background: Synovial sarcoma (SS) is a rare and aggressive soft tissue tumor. In a first study (Palmerini E, Cancer 2009) we analyzed clinical prognostic factors in a retrospective series of 250 patients (pts) who were treated at Rizzoli Institute between 1976 and 2006. Stage, age, size, histology and use of radiotherapy influenced survival, whereas the role of chemotherapy was unproven. In the present study on the same patient population, in order to identify new prognostic factors and potential therapeutic targets, a panel of markers involved in chemotaxis and tumor growth were assessed. Methods: The expression of the chemokine receptor CXCR4 (a marker for chemotaxis which plays a critical roles in cancer progression) and the insulin-like growth factor receptor-1 (IGFR1) (a marker of growth activation ) were evaluated by IHC staining. Results: Tissue samples were available for the analysis in 88 patients (45 female and 43 male); median age was 37 years (range 11-63); size of the lesion was > 5 cm in 60 patients (71%); histology was biphasic in 30 (34%) of patients. All pts underwent surgery, 56% of pts underwent adjuvant radiotherapy (RT) and 68% adjuvant chemotherapy. With a median follow-up of 6 years (1-30 years), the 5-year overall survival (OS) was 70% (60-81). A positive stain for IGFR1 was detected in 55 pts (62.5%), with expression in the nucleus in 21 pts. CXCR4 was expressed in 74 pts (84%), nuclear pattern in 31 pts. No relation between IGFR1 and CXCR4 expression and clinical variables was found. The 5-year OS was 63% (95%CI 41-85%) for pts with positive IGFR1/nuclear expression and 73% (95%CI 61-85%) p = 0.05, in pts with negative IGFR1/nuclear staining. Similarly, the 5-year OS was 47% (95%CI 27-66%) in patients with positive CXCR4/nuclear expression and 86% (95%CI 76-96%), p = 0.003, in negative cases. In a multivariate analysis including age, histology, size and use of RT, nuclear expression of IGFR1 and CXCR4 were confirmed statistically significant independent factor for OS. Conclusions: The nuclear expression of CXCR4 or IGFR1 negatively influences the survival in patients with SS. Further studies addressing the role of CXCR4 as a potential target in this high risk subgroup of SS patients are needed.

Sphere-forming cell subsets with cancer stem cell properties in human musculoskeletal sarcomas

Musculoskeletal sarcomas are aggressive malignancies often characterized by an adverse prognosis despite the use of intense multiagent chemotherapy or molecular targeted therapy in combination to surgery and radiotherapy. Stem-like cells identified within solid tumors have been recently implicated in drug resistance, metastasis and local relapse. Here, we report the identification of putative cancer stem cells (CSCs) in sarcomas using a sphere culture system. These sarcospheres, able to grow in anchorage-independent and serum-starved conditions, express the pluripotent embryonic stem cell marker genes OCT3/4, Nanog and SOX2. Expression levels of these genes were greater in sarcospheres than in the parental tumor cultures. Importantly, the isolated tumor spheres transplanted into mice were tumorigenic and capable of recapitulating the human disease. Finally, we demonstrated that low (1%) O2 conditions, reproducing those found within the tumor microenvironment, significantly increase the number and the size of sarcospheres. The sphere formation assay is, therefore, a valuable method for the isolation of putative CSCs from human sarcomas and its efficiency is improved by controlling oxygen availability. This method provides a reliable preclinical model that can be used for future studies aimed at investigating crucial aspects of sarcoma biology, such as resistance to treatments and relapse.

Molecular diagnosis in Ewing family tumors: the Rizzoli experience--222 consecutive cases in four years

The Ewing's family of tumors (EFTs) are characterized by chimeric transcripts generated by specific chromosomal rearrangements. The most common fusions are between the EWSR1 gene on chromosome 22 and the ETS family of transcription factors; rarely, FUS (on chromosome 16) substitutes for EWSR1. The detection of specific translocations using molecular analysis is now a routine part of the pathological examination of EFT. Here, we report our experience with molecular diagnosis of EFT during the 4 years (2006-2009) at the Rizzoli Institute. We analyzed 222 consecutive tumors with a presumptive diagnosis of EFT using molecular techniques and IHC. We found five distinct types of EWSR1-FLI1 fusion transcripts resulting from translocation t(11;22), three types of EWSR1-ERG transcripts resulting from t(21;22), and one type of t(2;22) resulting in EWSR1-FEV fusion. Molecular investigation validated 92% of cases ultimately diagnosed as EFT; IHC validated 76% of the cases. Thus, despite the difficulties and limitations associated with both molecular and IHC analysis on fresh and formalin-fixed, paraffin-embedded tissue, a combination of these techniques is the best approach to enhancing the accuracy of EFT diagnosis. We also present our method for choosing which molecular techniques to apply. Finally, we collected the most prevalent breakpoints reported in the literature, indicating which exons are involved, the sequence breakpoints, and the NCBI reference sequences.

Role of MMP-9 and its tissue inhibitor TIMP-1 in human osteosarcomaFindings in 42 patients followed for 1–16 years

BACKGROUND

The activity of matrix metalloproteinases (MMPs) in degrading extracellular matrix is controlled by activation of proenzymes and inhibition of MMP tissue inhibitors (TIMPs).

PATIENTS AND METHODS

To assess the proteolytic cascade imbalance in malignancy progression, tissue expression and serum levels of MMP-2, MMP-9 and of their inhibitors TIMP-2 and TIMP-1 respectively were evaluated in 42 selected patients with high-grade osteosarcoma (OS). MMP-2, MMP-9, TIMP-2 and TIMP-1 were studied in biopsies by immunohistochemistry and in serum by ELISA test. Patients were subdivided into 3 groups according to their follow up: continuously disease-free, diagnosis of metastasis during follow-up, and metastasis at diagnosis.

RESULTS

Immunohistochemistry demonstrated an imbalance between MMPs and TIMPs, with a more evident role for MMP-9 than for MMP-2 in tumor progression. TIMP-1 inhibitor in plasma was higher in patients with osteosarcoma than in a control group. This high value of TIMP-1 was particularly evident in the group of patients who later developed metastases and/or local recurrences, and in those with metastases at diagnosis.

INTERPRETATION

Our findings confirm the protective action of TIMP-1, as MMP inhibitor, but also show its activity as a growth factor underlining its multifunctional role in OS.

Genetic and molecular alterations in rhabdomyosarcoma: mRNA overexpression of MCL1 and MAP2K4 genes

Rhabdomyosarcoma, the most common soft tissue sarcoma in childhood, belongs to the small round cell tumor family and is classified according to its histopathological features as embryonal, alveolar and pleomorphic. In this study we propose to explore genetic alterations involved in rhabdomyosarcoma tumorigenesis and assess the level of mRNA gene expression of controlling survival signalling pathways. For genetic and molecular analysis, array-based comparative genomic hybridization, combined with Real Time PCR using the comparative method, was performed on 14 primary well-characterized human primary rhabdomyosarcomas. Multiple changes affecting chromosome arms were detected in all cases, including gain or loss of specific regions harbouring cancer progression-associated genes. Evaluation of mRNA levels showed in the majority of cases overexpression of MCL1 and MAP2K4 genes, both involved in cell viability regulation. Our findings on rhabdomyosarcoma samples showed multiple copy number alterations in chromosome regions implicated in malignancy progression and indicated a strong expression of MAP2K4 and MCL1 genes, both involved in different biological functions of complicated signalling pathways.

Altered expression of urokinase-type plasminogen activator and plasminogen activator inhibitor in high-risk soft tissue sarcomas

In recent years, classification of soft-tissue sarcomas (STS) has improved with cytogenetic analyses, but their clinical behavior is still not easily predictable. The aim of this study was to detect alterations in the urokinase-type plasminogen system, involved in tumor growth and invasion, by comparing mRNA levels of its components with those of paired normal tissues, and relating them with patient clinical course. Real-time PCR was performed on human STS cell lines and tissues from highly malignant STS, including leiomyosarcomas and malignant fibrous histiocytomas, to evaluate the expression of urokinase-type plasminogen activator (uPA), uPA receptor (uPAR) and plasminogen activator inhibitor-1 (PAI-1). Immunohistochemistry of gene products was also performed. Median mRNA values of all genes studied were higher in tumors than in paired normal tissues. In agreement with data on STS cell lines, significant up-regulation for uPA and PAI-1 genes compared to reference values was seen. Moreover, different levels of expression were related to histotype and metastatic phenotype. There was accordance between uPA mRNA and protein expression, while immunodetection of PAI-1 product was weak and scattered. Clearly, the controversial role of PAI-1 protein requires further biological analyses, but evident involvement of uPA/PAI-1 gene overexpression in STS malignancy may highlight a molecular defect useful in discriminating STS high-risk patients.

Growth inhibition and sensitization to cisplatin by zoledronic acid in osteosarcoma cells

Since osteosarcoma is a drug-resistant disease, the aim of the present study was to explore the possible interest of therapeutic approaches including nitrogen-containing biphosphonate zoledronic acid using osteosarcoma cell lines with different genetic backgrounds. Parental p53+/pRb+ U2-OS, p53-mutant U2-OS (U2-OS/175) and p53-/pRb- SAOS were sensitive to zoledronic acid with no significant differences in IC50 values. Analysis of cell cycle distribution revealed a time-dependent shifting of U2-OS cells towards G2 phase with cell cycle arrest in G2 phase at 96 h of exposure to the compound. Conversely, U2-OS/175 and SAOS cells responded to treatment with transient cell accumulation in S phase up to 48-72 h, respectively. Cell lines were exposed to increasing concentrations of cisplatin alone or combined with sub-toxic doses of zoledronic acid. A growth inhibitory effect was seen after combined treatment in U2-OS, otherwise resistant to cisplatin up to 100 ng/ml. Zoledronic acid did not efficiently sensitized U2-OS/175 and SAOS to cisplatin, thereby suggesting that different behavior may depend on p53 mutation. This data was confirmed in U2-OS cells where p53 expression was downregulated by RNA interference. Present findings indicate occurrence of sensitization to cisplatin by zoledronic acid in wild-type p53 osteosarcoma cells but not in p53-null cells nor in cells expressing a dominant-negative form of p53, supporting that wild-type p53 is required for synergistic interaction of cisplatin and zoledronic acid.

Molecular alterations of monophasic synovial sarcoma: loss of chromosome 3p does not alter RASSF1 and MLH1 transcriptional activity

Differential diagnosis of monophasic synovial sarcoma requires the detection of specific biological markers. In this study we evaluated the presence of molecular alterations in 15 monophasic synovial sarcomas. Multiple changes affecting chromosome arms were detected by CGH-array in all microdissected cases available, and an association between gain or loss of specific regions harbouring cancer progression-associated genes and aneuploid status was found. The most frequent alteration was loss of 3p including 3p21.3-p23 region that, however, did not involve the promoter regions of the corresponding genes, RASSF1 and MLH1. Using Real-Time PCR, mRNA levels of both resulted moderately high compared to normal tissue; however, the weak to absent protein expression suggests RASSF1 and MLH1 post-transcription deregulation. Moreover, immunohistochemical analysis revealed that both mesenchymal and epithelial antigens were present in diploid tumours. These findings confirm the genetic complexity of monophasic synovial sarcoma and underline the need to integrate different analyses for a better knowledge of this tumour, essential to investigate new diagnostic and prognostic markers.

Evaluation of p16 and Id1 status and endogenous reference genes in human chondrosarcoma by real-time PCR

Both the tumour suppressor, p16, and the helix-loop-helix transcription factor, Id1, have been assigned roles in tumour growth in general and appear to be involved in chondrosarcoma. Id1 has further been found to repress the expression of p16. Therefore, the mRNA expression of these two genes was studied by real-time PCR in a search for prognostic markers in human chondrosarcoma. To get reliable quantitative data, however, the choice of endogenous reference gene for use in the assay is important. Therefore, eleven different endogenous reference genes were evaluated in chondrosarcoma cells and articular chondrocytes. 18S rRNA appeared to be the best choice to use as endogenous reference gene, since it was suitable for both kinds of cells. Several of the other reference genes tested showed variation between individuals or between normal chondrocytes and chondrosarcoma cells. This demonstrates the importance of using a correct endogenous reference gene to get reliable results from quantitative measurements. Both p16 and Id1 showed varied gene expression patterns among the samples and none of these genes could be significantly correlated to prognosis.

Amplification of CDK4, MDM2, SAS and GLI genes in leiomyosarcoma, alveolar and embryonal rhabdomyosarcoma

We evaluated amplification and overrepresentation of CDK4, MDM2, GLI and SAS genes of the 12q13-15 region, in a group of soft tissue sarcomas including leiomyosarcomas (LMS), alveolar rhabdomyosarcomas (ARMS) and embryonal (anaplastic and classic variants) rhabdomyosarcomas (ERMS), to ascertain genomic alterations and possible differences within histologic subtypes of rhabdomyosarcoma (RMS). Quantitative real-time PCR was performed on DNA samples from 29 LMS, 9 ARMS, 7 anaplastic ERMS and 6 classic ERMS. Alteration of one or more of the 12q13-15 genes was revealed in 13/29 LMS (45%) and 12/22 RMS (54%) including 5/9 ARMS (56%), 5/7 anaplastic ERMS (71%) and 2/6 classic ERMS (33%). The potential importance of overproduction of protein products in neoplastic development, led us also to study a possible high expression of cdk4, mdm2 and gli proteins in immunohistochemical staining experiments on paraffin-embedded tissue samples of the same cases. Among LMS and RMS most cases with CDK4, MDM2 and GLI gene alterations also showed a simultaneous high expression of the relative protein. In summary, these results indicate that amplification or overerepresentation of genes at 12q13-15 region involve both LMS and RMS. Moreover these genes alterations reveal predominantly in the alveolar and in the anaplastic variant of the embryonal subtype. These two seem to have a more similar behavior than anaplastic and classic embryonal that are classified in the same subtype.

Proteases and interleukin-6 gene analysis in 92 giant cell tumorsof bone

BACKGROUND

Giant cell tumor of bone (GCT) is a benign tumor with a significant tendency to recur locally and rarely to produce pulmonary metastases. It is characterized by the presence of multinucleated osteoclast-like giant cells together with mononuclear spindle-shaped cells. Few prognostic markers have been reported to predict the clinical outcome of GCT patients, so is very important to find the factor that can be implicated in its potential aggressiveness.

PATIENTS AND METHODS

Different groups of GCT patients were selected for this study, including patients without evidence of disease and patients who recurred locally or with lung metastasis. The total of 92 tumor samples also included the specimens of the local recurrences and the lung metastases. By using immunohistochemistry and real-time quantitative polymerase chain reaction techniques, the genetic and proteic analyses were performed on the urokinase-type plasminogen activator (u-PA), its receptor (u-PAR) and its inhibitor (PAI-1), which have been described to be frequently implicated in the process of degradation of the extracellular matrix during the metastatic process. Interleukin-6 (IL-6), a cytokine released by GCT cells, which stimulates resorption of bone, was also analyzed.

RESULTS

IL-6, u-PA, u-PAR and PAI 1 genes were found amplified, respectively, in 7%, 5%, 8% and 12% of total cases (92). In particular, the percentages of amplified genes were higher in the GCT cells that gave rise to metastases (12 cases) and in the samples of lung metastases (nine cases) compared with the disease-free group of patients (60 cases).

CONCLUSIONS

These results suggest a possible association of these factors with a higher biological aggressiveness of GCT. Morever, it appears that increased expression of the IL-6, u-PA, u-PAR and PAI1 proteins might not depend on mutation of the corresponding genes.

Activation of metalloproteinases-2 and -9 by interleukin-1alpha in S100A4-positive liposarcoma cell line: correlation with cell invasiveness

BACKGROUND

The S100A4 gene may affect the invasive properties of tumor cells through modulation of metalloproteinases (MMPs) and their inhibitors (TIMPs).

MATERIALS AND METHODS

In the human liposarcoma cell line, SW872, we analyzed the expression of S100A4 protein by immunohistochemistry and flow cytometry. The production of MMP2, MMP9, TIMP1 and TIMP2 was assessed by gelatin zymography and enzyme-linked immunoabsorbent assay before and after interleukin-1alpha (IL-1alpha) and interleukin-6 (IL-6) stimulation; cell invasiveness was measured by Matrigel invasion assay.

RESULTS

S100A4-positive SW872 cells responded to IL-1alpha with induction of immunoreactive MMP2 and TIMP1 and with activation of both MMPs, the latter significantly associated with an increase of cell invasiveness. Treatment with IL-6 induced less significant variations resulting in a more stable invasive behavior.

CONCLUSION

These data show that S100A4-positive SW872 respond to interleukins by influencing the behavior of factors involved in extracellular matrix degradation and emphasize the predominant role of MMP activity status on the positive regulation of cell migration mechanisms.

Tissue and serum loss of metalloproteinase inhibitors in high grade soft tissue sarcomas

The activity of matrix metalloproteinases (MMPs) in degrading extracellular matrix is controlled by activation of pro-enzymes and inhibition of MMP tissue inhibitors (TIMPs). To assess proteolytic cascade imbalance in malignancy progression, the enzymatic activity of MMP2 and MMP9 and the expression and serum level of their inhibitors, TIMP2 and TIMP1 respectively, was evaluated in selected patients with high-risk soft tissue sarcoma (STS). Gelatinase activity and inhibitor expression was evaluated on 69 biopsies by zymography and immunohistochemistry. TIMP1 and TIMP2 serum concentration was tested in 53 STS patients and in 56 controls using a sandwich enzyme immunoassay. Clinical and biological variables were related to clinical outcome of the patients. A significant gelatinolytic activity was seen in a high percentage of STS. TIMP expression was weak or negative in the majority of samples. The difference between disease-free (p=0.001) and overall survival (p=0.007) curves based on TIMP2 immunoreactivity was statistically significant. TIMP plasma concentration of 53 STS revealed significantly lower levels compared to those of 56 controls (p=0.0001). In conclusion, low levels of negative regulators of proteolysis may be related to tumor biological aggressiveness and used to select patients with poor prognosis to improve cure.

Identification of markers of possible prognostic value in 57 giant cell tumors of bone

Giant cell tumor of bone (GCT) is a neoplasm characterized by the presence of large numbers of multinucleated osteoclast-like giant cells, together with mononuclear spindle-shaped cells. Although GCT can be considered a benign lesion, it may exhibit a high biological aggressiveness, which is often associated with enhanced osteolytic properties and development of lung metastasis. By selecting different groups of GCT patients, including patients without evidence of relapse after a median follow-up of 114 months and patients who recurred with lung metastasis, this study focused on the analysis of the expression at clinical onset and in the metastasis of a series of markers involved either in bone resorption modulation or in the metastatic process. By using immunohistochemistry, we analyzed the expression of interleukin-6 (IL-6), a cytokine stimulating bone resorption that has been demonstrated to be released by GCT cells. The expression of factors of the urokinase-type plasminogen activation system, including the urokinase-type plasminogen activator (u-PA) and the plasminogen activator inhibitor type 1 (PAI-1), which have been described to be frequently implicated in the process of degradation of the extracellular matrix during the metastatic process, were also analyzed. Finally, since the action of plasminogen activators is facilitated by the presence of specific receptors on cell surfaces, the analysis included also the u-PA receptor (u-PAR). Our results showed that all these proteins were variably either expressed or overexpressed both in primary tumors and lung metastasis. However, both the level of expression and the incidence of overexpression were higher in primary GCT that relapsed and in lung metastasis compared to primary tumors from disease-free patients, suggesting a possible association of these proteins with a higher biologic aggressiveness of GCT cells. The parallel analysis of a group of primary tumors and of their respective lung metastasis demonstrated that the enhanced expression of one or more of these proteins may confer a selective advantage to GCT cells in terms of systemic invasiveness. Therefore, the evaluation of the expression levels of these proteins at the time of diagnosis may be taken into consideration for a classification of GCT into categories characterized by a different risk to relapse.

Involvement of INK4A gene products in the pathogenesis and development of human osteosarcoma

BACKGROUND

The INK4A tumor suppressor gene plays a crucial role in the regulation of the G1 cell cycle phase. It encodes two transcripts, p16 and p14 alternate reading frame (ARF), involved in retinoblastoma protein (pRb)- and p53- cell growth control pathways, respectively.

METHODS

To define the role of gene status and molecule expression involved in the INK4A regulatory system, immunohistochemistry, immunoblotting, and polymerase chain reaction (PCR) analysis were performed on 35 primary high grade osteosarcomas (OS).

RESULTS

Although p16 and p14ARF proteins were found negative or weakly detectable in 60% and 57% of the cases respectively, INK4A gene analysis of exons 1alpha, 1beta and 2 did not reveal any deletion or mutation. However, methylation status of the 5'CpG promoter region, assessed by methylation-specific PCR, was found in 12 out of 21 OSs with negative or weak p16 expression. A statistical analysis based on pRb/p16 and p53/p14ARF staining status showed that pRb and p16 co-expression was inversely correlated to tumor relapse and was a marker for a more favorable prognosis. A statistically significant inverse correlation was found between wt-p53 and p14ARF expression. In the group of wt-p53 tumors, the loss of p14ARF was associated with a decreased expression of p21 protein, suggesting a down-regulation of the transcriptional activity of p53.

CONCLUSIONS

The current results suggest that, in OS, the altered expression of INK4A products plays a primary role in the deregulation of both pRb and p53 cell growth control pathways, contributing to tumor pathogenesis and development.

Metalloproteinase expression and prognosis in soft tissue sarcomas

BACKGROUND

Degradation of extracellular matrix by tumor-associated proteases can promote cell invasion and metastasis. This study assessed the prognostic role of MMP2, MMP9 metalloproteinases, and of the metalloproteinase inhibitor TIMP2, related to disease-free survival (DFS), in soft tissue sarcoma (STS) patients.

MATERIALS AND METHODS

Level and distribution of MMP2, MMP9, and TIMP2 expression were evaluated on 73 biopsies by immunohistochemistry and immunoblotting. Biopsies included 29 liposarcomas, 29 synovial sarcomas, and 15 malignant peripheral nerve sheath tumors (MPNST). Association between DFS and overall survival with different variables was assessed.

RESULTS

In terms of DFS, increased MMP2 reactivity and lack of TIMP2 expression were significant for poor prognosis in all samples (P = 0.0005 and P = 0.006 respectively). MMP2 correlated to histologic grade (P = 0.005). Lack of TIMP2 expression was a poor prognostic factor for DFS in synovial sarcoma (P = 0.009), while MMP2 and MMP9 correlated with metastasis (P = 0.008 and P = 0.005, respectively) and grade (P = 0.001 and P = 0.04 respectively) in liposarcoma.

CONCLUSIONS

These prognostic markers that influence growth and spread of tumor cells might be useful to define tumor aggressiveness and risk of the metastasic event.

Analysis of 12q13-15 genes in parosteal osteosarcoma

The region q13-15 of chromosome 12 frequently is altered in human sarcomas, and several genes, such as SAS, CDK4, and MDM2, have been found to be amplified in bone and soft tissue sarcomas. These genes and their products were studied by quantitative polymerase chain reaction and immunohistochemical analysis in 25 parosteal osteosarcoma samples (22 Grades I or II, three dedifferentiated) to evaluate if the possible alterations detected of the genes on chromosome 12 could have a role in the development of this rare bone tumor. Immunohistochemical analysis was performed on formalin fixed, paraffin embedded tumor sections to evaluate CDK4 and MDM2 protein expression. To measure the degree of SAS and CDK4 gene amplification, quantitative polymerase chain reaction was done on deoxyribonucleic acid derived from the same samples. The results showed that CDK4 protein was expressed in 92% of the cases. Strong and uniform CDK4 and MDM2 immunoreactivity was found respectively in three of three and two of three dedifferentiated parosteal osteosarcomas. SAS and CDK4 genes were found to be amplified fourfold in two Grade II tumors and in one dedifferentiated tumor. These findings, which should be investigated further, might suggest a possible role of the chromosome 12 genes in the pathogenesis of parosteal osteosarcoma.

Brain tumors as second malignant neoplasms in patients with osteosarcoma treated with adjuvant and neoadjuvant chemotherapy: report of 2 cases

A malignant, primary brain tumor developed as Second Malignant Neoplasm (SMN) in 2/490 long-term-survivor osteosarcoma patients treated at our Institute over a 20-yr period. They developed the brain tumor (one astrocytoma and one glioblastoma) 3 and 5 yr after treatment, (chemotherapy and surgery), for localized osteosarcoma of the extremity.

Presence and expression of the simian virus-40 genome in human giant cell tumors of bone

SV40 DNA sequences have been found in human tumors, such as mesotheliomas, ependymomas, and bone tumors, suggesting that SV40 may be involved in their etiology. The FOS oncogene could play an important role in bone development because SV40 is able to induce FOS in cell culture. In this study, the presence of SV40 sequences, large T antigen (Tag), and FOS protein expression were investigated in 120 giant cell tumors (GCTs), moderately benign bone tumors that in some cases can progress to a malignant phenotype. Polymerase chain reaction (PCR), using primers that amplify the RB1 pocket binding domain and the intron of Tag, was used to analyze GCT for the presence of SV40 DNA. Tag and FOS protein expression was evaluated by immunohistochemistry. SV40 sequences were found in 30/107 GCTs, and of these, 22/30 samples expressed Tag protein (73%) and 15/30 overexpressed the FOS oncogene (50%). FOS was undetectable in 77 SV40-negative GCTs. Sequence analysis of the amplified DNAs confirmed that the amplified sequences corresponded to SV40 DNA. The correlation between FOS overexpression and SV40-positive GCTs was highly statistically significant (P < 0.001). These results show that SV40 DNA sequences and SV40 Tag are present in GCTs and might induce FOS activity. These data suggest that SV40 might play a role in the development and progression of some GCTs.

Alteration of pRb/p16/cdk4 regulation in human osteosarcoma

Cell-cycle regulation depends on a fine balance between cyclin-cyclin-dependent kinase complexes and a family of kinase inhibitors that bind cyclin-cdk complexes and block their activity. To investigate the role of mechanisms regulating cell-cycle progression in human osteosarcomas (OS), pRb/p16/cdk4 expression was analyzed in 39 high-grade OS; 19 of these developed metastasis during follow-up. Positive reaction for functional pRB was shown by 18/39 (46%) OS, while 21/39 (54%) were negative. A higher probability of metastasis was seen in patients with negative pRb expression (p < 0.05). Furthermore, while functional pRb and D1 expression are inversely associated to metastasis occurrence, the presence of D1/cdk4 complex in our study was related to poor prognosis. We found that 10/18 pRb-positive and 14/21 pRb-negative tumors were p16-positive. No significant correlation was found between pRb and p16 expression. On the other hand, high cdk4 levels in p16-positive tumors as compared with p16-negative tumors resulted in a positive association between p16 and cdk4 expression (Chi squared = 5.98; p = 0.01). No extensive p16INK4A genomic alterations were found in tumors lacking p16-protein expression. To determine which mechanisms are involved in the down-regulation of p16 protein, the methylation status of the p16INK4 gene was evaluated on the 15 p16-negative tumors: 8 samples showed 5' CpG-island methylation; 4/8 had a complete methylation status, while in the remaining 4 the gene was only partially methylated. These data confirm the role of the pRb/p16/cdk4 pathway in OS development.

Secondary tumors in bone sarcomas after treatment with chemotherapy

New oncologic treatments have improved survival in osteosarcoma and Ewing's sarcoma. However, these treatments may cause secondary malignancies after radiotherapy. This study evaluated the incidence of secondary malignancies after neoadjuvant chemotherapy. Between April 1972 and December 1990, 518 osteosarcoma and 299 Ewing's sarcoma patients entered neoadjuvant chemotherapy protocols. Follow-up records of all patients were analyzed and malignant tumors were reported. Nine patients developed another malignancy, including 5 leukemias, 1 astrocytoma, 1 liposarcoma, 1 parotid, and 1 breast carcinoma. Four leukemias were found in patients treated for osteosarcoma with chemotherapy, but not radiotherapy. Only one leukemia developed after Ewing's sarcoma treated with chemotherapy and radiotherapy. The incidence of leukemias is high, while the other tumors can be explained as unrelated cases. Incidence densities for leukemia were calculated for both groups of patients. Treated osteosarcoma patients seem to have a predisposition to develop leukemias, but whether this is chemotherapy induced needs to be investigated.

Expression of G1 phase regulators in MG-63 osteosarcoma cell line

Cyclins and cyclin-dependent kinases (cdks) form complexes that govern transitions during cell cycle phases. In this study we characterized a human osteosarcoma cell line, MG-63, for the expression level of cyclin D1, cyclin E, cdk4, cdk2, and cell cycle inhibitors pRb and p21. To investigate the role of these proteins we treated MG-63 cells with tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6). Cell proliferation analysis demonstrated an increased proliferation of MG-63 cells with IL-6, while TNF-alpha acted as an anti-proliferative agent. Immunoblotting revealed an increased expression of p21 with TNF-alpha and its complex with cdk2. TNF-alpha reduced the expression of the cyclin E-cdk2 complex. TNF-alpha did not affect the amount of cyclin D1, cyclin E, cdk4, cdk2, and of cyclin D1-cdk4 complex. IL-6 decreased p21 expression and its complex with cdk2, while it increased the cyclin E-cdk2 complex. Cyclin D1 and cdk4 expression and their complex did not change after IL-6 treatment, nor did cyclin E and cdk2 protein expression. Hyperphosphorylated/dephosphorylated Rb protein ratio was reduced with TNF-alpha whereas it increased with IL-6. These results may suggest an important role of p21 and of cyclin E-cdk2 complex in the G1 phase regulation through pRb phosphorylation in MG-63 cells.

Analysis of SAS gene and CDK4 and MDM2 proteins in low-grade osteosarcoma

The region q13-15 of chromosome 12 contains SAS, CDK4, and MDM2 genes that are rearranged or amplified in a variety of human sarcomas. This study evaluated SAS gene amplification, and MDM2 and CDK4 protein expression in 20 tumor samples of central low-grade osteosarcoma (16 primary, 3 recurrences, 1 lung metastasis). SAS amplification was analyzed by quantitative polymerase chain reaction (PCR), while from the same paraffin-embedded samples, MDM2 and CDK4 protein expression was evaluated by immunohistochemistry. MDM2 and CDK4 proteins were found strongly expressed in 35% and 65%, respectively, of the samples. SAS was found amplified in 15% of the samples. These findings indicate that these genes may be involved in tumorigenesis and progression of low-grade osteosarcoma.

C-myc and c-fos in human osteosarcoma: prognostic value of mRNA and protein expression

The c-myc and c-fos proto-oncogenes have several putative functions, including regulation of cell growth. In many neoplasms c-myc overexpression has been linked to poor prognosis. In order to study the role of c-myc and c-fos expression on the tumorigenesis, and the metastatic spread of osteosarcoma, frozen and paraffin-embedded tissue 38 primary osteosarcoma and 10 lung metastases were analyzed. The mRNA analysis was performed by quantitative reverse transcription-polymerase chain reaction and in situ hybridization. The protein expression was studied by Western blot analysis and immunohistochemistry. C-myc and c-fos were found overexpressed in a high percentage of the relapsed tumors and of the metastases, and overexpression of both oncogenes in the same tumor was strongly correlated to the development of metastases (p < 0.05), as 6 of the 7 primary tumors overexpressing both the oncogenes gave metastases. In conclusion, both c-myc and c-fos are involved in the growth and spread of osteosarcoma and a synchronous overexpression of both oncogenes is highly significant for a metastatic potential of a primary tumor.

Correlation between apoptosis and TP53 status in osteosarcoma

Samples of 18 osteosarcomas were examined for the occurrence of apoptosis and TP53 status. Apoptosis was investigated by an in situ nick translation technique on paraffin-embedded samples. It was found that apoptosis rarely occurs in osteosarcoma at the early stage of disease, whereas it is frequently activated when tumors are treated with antiblastic drugs. The analysis of the TP53 gene showed no mutation at diagnosis; whereas, during disease progression, four cases showed TP53 mutations. The authors discuss the relation between apoptosis, TP53 status, and therapy.

Comparative genomic hybridization of low-grade central osteosarcoma

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

Prognostic significance of cyclin expression in human osteosarcoma

To evaluate the distribution of cyclin protein expression, in relation to cell proliferation rate and clinical behavior, an immunohistochemical study was performed on 92 tumor samples of patients with high grade osteosarcoma (OS). A large cyclin A- and cyclin E-positive fraction was found respectively in 59% and 47% of the osteosarcomas, while immunostaining for cyclin D1 was weak or absent in most tumor samples. A positive, statistically significant correlation was found between A and E cyclins and Ki67 expression (p<0.001). Disease-free survival (DFS) analysis included 69 of the 92 patients. A significantly higher probability of metastasis was seen in patients lacking cyclin D1 compared to those in which cyclin D1 was positive (p<0.01). Conversely, patients with >40% of cyclin A-positive cells relapsed more frequently than those with <40% of cyclin A-positive cells (p<0.05). The multivariate analysis demonstrated that cyclin A had a lower predective risk in terms of disease-free survival as opposed to the loss of cyclin D1 that is considered a powerful prognostic factor.

Adhesion molecules in high-grade soft tissue sarcomas: correlation to clinical outcome

The extracellular matrix (ECM) forms a framework for cell adhesion, but it also regulates growth and differentiation. Normal and malignant cells interact with the ECM via specific receptors, the integrins. To explore the mechanisms of growth and spread in soft tissue sarcomas the expression of the major ECM molecules and their corresponding integrin receptors were studied by immunohistochemistry in high-grade soft tissue sarcomas: malignant fibrous histiocytoma (20 cases), malignant peripheral nerve sheath tumour (17 cases) and synovial sarcoma (21 cases). The expression pattern was compared with cell proliferation and clinical outcome. Integrins were found to be expressed according to histological pattern. In synovial sarcomas, the epithelial component showed a high alpha 2 but negative or minimal detection of alpha 5 expression, while a weak alpha 2 expression and a moderate alpha 5 expression were found in the spindle cell component. No alpha 2 expression was detected in malignant fibrous histiocytoma, and minimal alpha 5 expression was detected in malignant schwannoma. The alpha 6 expression levels were positively correlated with the occurrence of metastases in all types of sarcomas studied. The expression of ECM molecules was downregulated and irregular in most tumours. In conclusion, the divergent integrin expression pattern could be useful in the diagnosis and classification of soft tissue sarcomas. Furthermore, since high laminin receptor expression correlates with occurrence of metastases, it could become a useful prognostic marker.

Prognostic relevance of C-myc gene expression in giant-cell tumor of bone

Giant-cell tumor is a primary bone tumor, of uncertain origin, with the potential capacity to metastasize. To study the role of c-myc and c-fos oncogene overexpression in the tumorigenesis and metastatic spread of giant-cell tumors, 32 primary tumors were collected; of these, 19 remained disease-free and 13 metastasized to the lung. Samples of lung metastasis from these 13 patients were also available for study. The expression of c-myc and c-fos mRNA was studied by reverse transcription-polymerase chain reaction and by in situ hybridization. The expression of protein was studied by Western blot analysis and by immunohistochemistry. C-myc mRNA was overexpressed in 12 (38%) of the 32 primary tumors. Thirteen primary tumors metastasized to the lung; in nine (69%) of these, c-myc mRNA was overexpressed. The c-myc protein was overexpressed in seven (54%) of the 13 tumors that metastasized to the lung. C-fos was overexpressed in only one lung metastasis. A strong correlation between the overexpression of c-myc, and the occurrence of metastases was found: thus, c-myc seems a powerful prognosticator in giant-cell tumor. C-myc was overexpressed both in giant cells and in mononuclear cells, suggesting that both cell types are involved in the progression of this tumor.

Altered G1 phase regulation in osteosarcoma

Alterations in the normal cell cycle lead to abnormal cell proliferation and to tumor development. To explore the role of the cyclin D/Cdk4 complex and the retinoblastoma protein (pRb) in the growth and spread of osteoblastic osteosarcoma (OS), 40 tumor samples were selected. In 17 of these cases, lung metastases occurred during follow-up. Expression of pRb, cyclin D1 and its catalytic subunit, Cdk4, was studied by immunohistochemistry and immunoblotting. As controls, non-neoplastic tissues surrounding the tumor were used. The expression level and pattern were compared to clinical outcome. Cdk4 was over-expressed in 80% of OS, independently of clinical outcome, and showed an intense and uniform distribution in tumor cells compared to normal cells. However, co-immunoprecipitation of Cdk4 with cyclin D1 revealed low levels of cyclin D/Cdk4 complex; 20 of 40 OS examined had a negative or minimal immunostaining for active pRb. The probability of relapse was significantly higher in pRb-negative than in the -positive patients (p < 0.05). The ratio of unphosphorylated/hyperphosphorylated pRb was lower in relapsed patients than in patients with no evident disease, though the difference was not statistically significant. High levels of pRb/cyclin D1 were found in all samples exhibiting functional pRb expression. Our results show that G1 phase deregulation is involved in formation and development of OS. The expression levels of both pRb and cyclin D1 had a clear correlation with clinical outcome, suggesting that these parameters could be used as prognostic markers.