Detection of t(11;22)(q24;q12) translocation of Ewing's sarcoma in paraffin embedded tissue by nested reverse transcription-polymerase chain reaction

Monophasic Synovial Sarcoma in the Elbow Misclassified but Successfully Treated as Ewing's Sarcoma with Chemotherapy

To the best of the authors’ knowledge, this is the first published case of monophasic synovial sarcoma (SS) initially diagnosed as Ewing’s sarcoma (ES), yet successfully treated with chemotherapy in a 24-year-old patient. The initial diagnosis showed a monotonous round cell tumor and positivity for CD99, characteristic of ES; however, the cytology was negative for the classic EWSR1 rearrangement of ES. The patient was treated with the standard chemotherapy protocol of ES – COG AEWS1031 Regimen A with vincristine, doxorubicin, cyclophosphamide, and mesna – as well as with wide resection. Post-resection tissue submission showed additional morphologic features which led to a re-evaluation of the classification of the tumor as well as additional molecular studies; these revealed positivity for translocations of SS18 (18q11.1) in 100% of the nuclei, which is most characteristic of SS, thus, reclassifying the neoplasm as a SS tumor. This case underscores the importance of considering several pathologic entities in the differential diagnosis of small, round blue cell tumors, including ES, SS, and lymphoma. It also demonstrates the importance of using chromosomal identification for a more definitive diagnosis, rather than relying on histological features and markers which are found in more than one tumor classification. There is conflicting evidence of the impact of chemotherapy on survival in SS, as it is primarily treated with radiation therapy. Since SS is rare, prospective studies on the effect of chemotherapy on survival are limited in number. However, our case study demonstrates that chemotherapy is another modality that can be used in the treatment of SS neoplasms.

Molecular strategies for detecting chromosomal translocations in soft tissue tumors (review)

Approximately one third of soft tissue tumors are characterized by chromosomal aberrations, in particular, translocations and amplifications, which appear to be highly specific. The identification of fusion transcripts not only supports the diagnosis, but provides the basis for the development of novel therapeutic strategies aimed at blocking the aberrant activity of chimeric proteins. Molecular biology, and in particular, cytogenetic and qualitative and quantitative polymerase chain reaction technologies, allow with high efficiency and specificity, the determination of specific fusion transcripts resulting from chromosomal translocations, as well as the analysis of gene amplifications. In this review, various molecular techniques that allow the identification of translocations and consequent fusion transcripts generated are discussed in the broad spectrum of soft tissue tumors.

Malignant small round cell tumors

Malignant small round cell tumors are characterised by small, round, relatively undifferentiated cells. They generally include Ewing's sarcoma, peripheral neuroectodermal tumor, rhabdomyosarcoma, synovial sarcoma, non-Hodgkin's lymphoma, retinoblastoma, neuroblastoma, hepatoblastoma, and nephroblastoma or Wilms’ tumor. Other differential diagnoses of small round cell tumors include small cell osteogenic sarcoma, undifferentiated hepatoblastoma, granulocytic sarcoma, and intraabdominal desmoplastic small round cell tumor. Differential diagnosis of small round cell tumors is particularly difficult due to their undifferentiated or primitive character. Tumors that show good differentiation are generally easy to diagnose, but when a tumor is poorly differentiated, identification of the diagnostic, morphological features is difficult and therefore, no definitive diagnosis may be possible. As seen in several study reports, fine needle aspiration cytology (FNAC) has become an important modality of diagnosis for these tumors. The technique yields adequate numbers of dissociated, viable cells, making it ideally suitable for ancillary techniques. Typically, a multimodal approach is employed and the principal ancillary techniques that have been found to be useful in classification are immunohistochemistry and immunophenotyping by flow cytometry, reverse transcriptase polymerase chain reaction (RT-PCR), fluorescence in situ hybridization (FISH), and electron microscopy. However, the recent characterization of chromosomal breakpoints and the corresponding genes involved in malignant small round cell tumors means that it is possible to use molecular genetic approaches for detection.

Taqman genotyping assays can be used on decalcified and paraffin-embedded tissue from patients with osteosarcoma

BACKGROUND

In cancers like osteosarcoma with a 5-year overall survival of 50-60%, archived histological specimens can be a useful source of biological material. However, this material generally has been decalcified and formalin-fixed for many years. In our study, we investigated whether DNA obtained from these tissues can be used for reliable single nucleotide polymorphism (SNP) genotyping.

PROCEDURE

We studied two SNPs in the drug transporter MDR1 using Taqman® SNP genotyping assays. Genotypes of the germ line DNA derived from freshly isolated DNA of 20 surviving patients with osteosarcoma were compared with genotypes obtained from archived material from decalcified formalin-fixed, paraffin-embedded (FFPE) blocks of the same patients.

RESULTS

Decalcified FFPE-derived DNA yielded smaller PCR fragments compared to DNA extracted from peripheral blood cells, with a reliable size of ∼200 bp. However, we were able to evaluate each SNP in 19 of 20 cases included in this study. All successfully genotyped samples showed 100% concordance between genotypes obtained from DNA of FFPE tissue and the genotypes obtained from DNA of blood from the same patients.

CONCLUSIONS

In conclusion, we have demonstrated that decalcified FFPE tissue can be used for genetic polymorphism analysis using Taqman® allelic discrimination assays. This forms a unique opportunity to combine new insights in genetic research with historical patient cohorts.

Survivin expression levels as independent predictors of survival for osteosarcoma patients

Survivin expression has been detected in various cancers and correlations have been recognized between the level of expression of this gene in tumors and prognosis. However, the aforementioned authors did not evaluate correlations between prognosis and survivin expression levels using surgically resected samples. In this study, we retrospectively investigated outcomes by examining the correlations between expression of this gene and clinicopathological parameters. Biopsy and resected specimens from which paraffin-embedded tissues could be extracted, were available from 16 patients in our hospital. We used the RT-PCR method and conducted a densitometric analysis to determine the ratio of survivin relative to h-GAPDH as an internal marker. Expression of survivin mRNA was detected in all samples. There was a significant negative correlation between survivin expression levels and duration of follow up, in months, using the Spearman's rank for the initial biopsy samples (rho=-0.775, p<0.01) and those obtained after chemotherapy (rho=-0.687, p<0.01). Moreover, Cox multivariate regression identified the survivin expression levels in both biopsy and post-chemotherapy samples as independent predictors of survival. We conclude that survivin levels in both initial biopsy and post-chemotherapy samples are useful prognostic indicators.

Survivin as a prognostic factor for osteosarcoma patients

Purpose: Survivin is one of the apoptosis inhibitor genes and is rarely expressed in adult ­tissues. However, survivin expression has been detected in various human cancers and ­correlations have been recognized between the level of expression of this gene in tumors and prognosis. In this study, we investigated the correlations between survivin mRNA expres­sion in osteosarcoma tissues and clinicopathological parameters.

Methods: There were 22 osteosarcoma patients in our hospital with paraffin-embedded ­tissues which could be extracted from biopsy specimens. We used the RT-PCR method after extracting total RNA and conducted a densitometric analysis to determine the ratio of survivin relative to h-GAPDH as an internal marker.

Results: Expression of survivin mRNA was detected in all osteosarcoma samples. Patients with metastasis had high survivin mRNA levels in initial biopsy specimens (p<0.01). Moreover, there was a statistically significant difference in survivin mRNA expression between ­patients with and without metastasis (p<0.01).

Conclusion: We concluded that high levels of survivin mRNA expression suggest poor prognosis for osteosarcoma patients.

Ewing's sarcoma of bone: the detection of specific transcripts in a large, consecutive series of formalin-fixed, decalcified, paraffin-embedded tissue samples using the reverse transcriptase-polymerase chain reaction

AIMS

(i) To report on the routine use of the reverse transcriptase-polymerase chain reaction (RT-PCR) technique on decalcified or non-decalcified, formalin-fixed, paraffin-embedded tissue (FFPET) for translocation detection, with particular emphasis on improved RNA extraction methodology and the use of PCR primers designed to generate small amplicons. (ii) To report on the relative incidences of translocation types and transcript variants in a large, single institution series of Ewing's sarcoma of bone.

METHODS AND RESULTS

Using RT-PCR to detect specific transcript variants, we analysed FFPET from 54 consecutive cases of Ewing's sarcoma of bone. We used 'gold standard' detection methods on corresponding fresh and fresh frozen tissue to validate the technique. We have demonstrated the effective use of RT-PCR on decalcified and non-decalcified FFPET samples for sarcoma-specific translocation detection (96% sensitivity, 100% specificity). Tissue decalcification did not affect the detection rate. The relative incidence of Ewing's sarcoma-specific translocation types and transcript variants was entirely consistent with previously published data.

CONCLUSIONS

With equal effectiveness, RT-PCR can be applied to both acid decalcified and non-decalcified FFPET for (Ewing's sarcoma) translocation detection and the technique can be introduced into routine practice in histopathology departments.

Primary synovial sarcoma of the kidney: Report of a case confirmed by molecular detection of the SYT-SSX2 fusion transcripts

We describe an unusual case of primary synovial sarcoma of the kidney. A 47-year-old woman had a tumor massively replacing the right kidney. There were no primary extrarenal neoplastic lesions. Microscopically, the tumor was composed of a cellular proliferation of relatively uniform spindle-shaped cells having atypical spindle or oval nuclei arranged in fascicles with tumor necrosis, without epithelial areas. Immunohistochemically, a small number of the tumor cells were positive for epithelial markers such as cytokeratin and epithelial membrane antigen. The SYT-SSX2 fusion transcripts were detected by a reverse transcription-polymerase chain reaction (RT-PCR) using RNA extracted from formalin-fixed, paraffin-embedded tissue. ETV6-NTRK3 fusion gene transcripts that result from t(12; 15)(p13;q25), which is characteristic of cellular congenital mesoblastic nephroma, were not demonstrated. To our knowledge, this is the ninth case of primary renal synovial sarcoma. This case report indicates that synovial sarcoma should be taken into account for the differential diagnosis of renal spindle cell tumors and the molecular assay detecting the SYT-SSX fusion transcripts is useful for the final diagnosis of synovial sarcoma arising in an unusual location.

Genetics and the biologic basis of sarcomas

Identification of genetic alterations has contributed greatly to the understanding of sarcoma biology. Additionally, detection of these abnormalities is providing new tools for the diagnosis of sarcomas. In this paper, three important new genetic findings from the past year are reviewed, including the t(12;15) translocation of congenital fibrosarcoma, mutation of the putative tumor suppressor gene hSNF5/INI1 in malignant rhabdoid tumor, and the association of c-kit mutations with gastrointestinal stromal tumor. Highlighted are important studies concerning mechanisms of chromosomal translocation, functions of sarcoma-specific fusion proteins, genetic abnormalities other than translocations, molecular diagnosis, and molecular profiling of gene expression. Particular emphasis is placed on information obtained with comparative genomic hybridization and microarray techniques, because these powerful technologies will facilitate the rapid acquisition of data that provide insight into the molecular genetic and biologic basis of sarcomas.