Over the last 20 years, a number of tumor-specific chromosomal translocations and associated fusion genes have been identified for mesenchymal neoplasms including adipocytic tumors. The addition of molecular cytogenetic techniques, especially fluorescence in situ hybridization (FISH), has further enhanced the sensitivity and accuracy of detecting nonrandom chromosomal translocations and/or other rearrangements in adipocytic tumors. Indeed, most resent molecular cytogenetic analysis has demonstrated a translocation t(11;16)(q13;p13) that produces a C11orf95-MKL2 fusion gene in chondroid lipoma. Additionally, it is well recognized that supernumerary ring and/or giant rod chromosomes are characteristic for atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma, and amplification of 12q13–15 involving the MDM2, CDK4, and CPM genes is shown by FISH in these tumors. Moreover, myxoid/round cell liposarcoma is characterized by a translocation t(12;16)(q13;p11) that fuses the DDIT3 and FUS genes. This paper provides an overview of the role of conventional cytogenetics and molecular cytogenetics in the diagnosis of adipocytic tumors.

A valuable diagnostic adjunct and important prognostic parameter in alveolar rhabdomyosarcoma (ARMS) is the identification of translocations t(2;13)(q35;q14) and t(1;13)(p36;q14), and the associated PAX3-FKHR and PAX7-FKHR fusion transcripts, respectively. Most RMS fusion gene type studies have been based on reverse transcriptase-polymerase chain reaction (RT-PCR) detection of the fusion transcript, a technique limited by RNA quality and failure of devised primer sets to detect unusual variants. As an alternative approach, we developed a fluorescence in situ hybridization (FISH) assay that can: (1) distinguish between the two most common ARMS-associated fusion genes; (2) identify potential unusual variant translocations; (3) assess histologic components in mixed alveolar/embryonal RMS; and (4) be performed on paraffinized tissue. FISH analyses of 75 specimens (40 ARMS, 16 ERMS, 8 mixed ARMS/ERMS, and 11 non-RMS tumors) using selected cosmid clone, bacterial, P1-derived, and yeast artificial chromosome probe sets were successful in all but two cases. Among specimens with informative results for both FISH and RT-PCR or standard karyotyping, PAX/ FKHR classification results were concordant in 94.6% (53/56). The three discordant cases included one exhibiting a t(2;13) by FISH that was subsequently confirmed by repeat RT-PCR, a second showing a rearrangement of the PAX3 locus only (consistent with the presence of a PAX3 variant translocation), and a third revealing a t(2;13) by FISH that lacked this translocation cytogenetically. Both alveolar and embryonal components of the mixed ARMS/ERMS subtype were negative for PAX3, PAX7, and FKHR rearrangements, a surprising finding confirmed by RT-PCR and/or conventional karyotyping. These data demonstrate that FISH with newly designed probe sets is a reliable and highly specific method of detecting t(1;13) and t(2;13) in routinely processed tissue and may be useful in differentiating ARMS from other small round cell tumors. The findings also suggest that FISH may be a more sensitive assay than RT-PCR in some settings, capable of revealing variant translocations.

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Epithelioid sarcoma (ES) is a relatively rare, highly malignant soft tissue sarcoma. The mainstay of treatment is resection or amputation. Currently other therapeutic options available for this disease are limited. Therefore, a novel therapeutic option needs to be developed. In the present study, we established a new human ES cell line (ESX) and analyzed the characteristics of its cancer stem-like cells/cancer-initiating cells (CSCs/CICs) based on ALDH1 activity. We demonstrated that a subpopulation of ESX cells with high ALDH1 activity (ALDHhigh cells) correlated with enhanced clonogenic ability, sphere-formation ability, and invasiveness in vitro and showed higher tumorigenicity in vivo. Next, using gene expression profiling, we identified CD109, a GPI-anchored protein upregulated in the ALDHhigh cells. CD109 mRNA was highly expressed in various sarcoma cell lines, but weakly expressed in normal adult tissues. CD109-positive cells in ESX predominantly formed spheres in culture, whereas siCD109 reduced ALDH1 expression and inhibited the cell proliferation in vitro. Subsequently, we evaluated the expression of CD109 protein in 80 clinical specimens of soft tissue sarcoma. We found a strong correlation between CD109 protein expression and the prognosis (P = 0.009). In conclusion, CD109 might be a CSC/CIC marker in epithelioid sarcoma. Moreover, CD109 is a promising prognostic biomarker and a molecular target of cancer therapy for sarcomas including ES.

Over 90% of Ewing sarcoma/primitive neuroectodermal tumors (PNETs) feature an 11;22 translocation leading to an EWSR1-FLI1 fusion. Less commonly, a member of the ETS-transcription factor family other than FLI1 is fused with EWSR1. In this study, cytogenetic analysis of an extraskeletal Ewing sarcoma/PNET revealed a novel chromosomal translocation t(4;22)(q31;q12) as the sole anomaly. Following confirmation of an EWSR1 rearrangement by the use of EWSR1 breakpoint flanking probes, a fluorescence in situ hybridization positional cloning strategy was used to further narrow the 4q31 breakpoint. These analyses identified the breakpoint within RP11-481K16, a bacterial artificial chromosome (BAC) clone containing two gene candidates FREM and SMARCA5. Subsequent RACE, RT-PCR, and sequencing studies were conducted to further characterize the fusion transcript. An in-frame fusion of the first 7 exons of EWSR1 to the last 19 exons of SMARCA5 was identified. SMARCA5 encodes for hSNF2H, a chromatin-remodeling protein. Analogous to EWSR1-ETSexpressing NIH3T3 cells, NIH3T3 cells expressing EWSR1-hSNF2H exhibited anchorage-independent growth and formed colonies in soft agar, indicating chimeric protein tumorigenic potential. Conversely, expression of EWSR1-hSNF2H in NIH3T3 cells, unlike EWSR1-ETS fusions, did not induce EAT-2 expression. Mapping analysis demonstrated that deletion of the C-terminus (SLIDE or SANT motives) of hSNF2H impaired, and deletion of the SNF2_N domain fully abrogated NIH3T3 cell transformation by EWSR1-SMARCA5. It is proposed that EWSR1-hSNF2H may act as an oncogenic chromatin-remodeling factor and that its expression contributes to Ewing sarcoma/primitive neuroectodermal tumorigenesis. To the best of our knowledge, this is the first description of a fusion between EWSR1 and a chromatin-reorganizing gene in Ewing sarcoma/PNET and thus expands the EWSR1 functional partnership beyond transcription factor and zinc-finger gene families.

IntroductionMyositis ossificans is a benign, self-limiting condition that usually affects young, athletically active men. To the best of our knowledge, this case report describes the oldest recorded patient with myositis ossificans.Case presentationOur patient was an 83-year-old Japanese woman who presented with a one week history of a palpable mass in the left thigh. She had a history of surgery for transverse colon cancer and lung cancer at the ages of 73 and 80, respectively. Clinical and radiological examinations suggested a malignant neoplasm such as metastatic carcinoma or extraskeletal osteosarcoma. A diagnosis of myositis ossificans was made by core needle biopsy. Our patient was asymptomatic and had no recurrence at one year follow-up.ConclusionClinicians should consider myositis ossificans as a possible diagnosis for a soft tissue mass in the limb of an older patient, thereby avoiding unnecessarily aggressive therapy.

Myxoid soft-tissue sarcomas represent a heterogeneous group of mesenchymal tumors characterized by a predominantly myxoid matrix, including myxoid liposarcoma (MLS), low-grade fibromyxoid sarcoma (LGFMS), extraskeletal myxoid chondrosarcoma (EMC), myxofibrosarcoma, myxoinflammatory fibroblastic sarcoma (MIFS), and myxoid dermatofibrosarcoma protuberans (DFSP). Cytogenetic and molecular genetic analyses have shown that many of these sarcomas are characterized by recurrent chromosomal translocations resulting in highly specific fusion genes (e.g., FUS-DDIT3 in MLS, FUS-CREB3L2 in LGFMS, EWSR1-NR4A3 in EMC, and COL1A1-PDGFB in myxoid DFSP). Moreover, recent molecular analysis has demonstrated a translocation t(1; 10)(p22; q24) resulting in transcriptional upregulation of FGF8 and NPM3 in MIFS. Most recently, the presence of TGFBR3 and MGEA5 rearrangements has been identified in a subset of MIFS. These genetic alterations can be utilized as an adjunct in diagnostically challenging cases. In contrast, most myxofibrosarcomas have complex karyotypes lacking specific genetic alterations. This paper focuses on the cytogenetic and molecular genetic findings of myxoid soft-tissue sarcomas as well as their clinicopathological characteristics.

Recurrent chromosomal translocations in neoplasms often generate hybrid genes that play critical roles in tumorigenesis. Desmoplastic small round-cell tumor (DSRCT) is an aggressive malignancy associated with the chromosomal translocation t(11;22)(p13;q12). This translocation generates a chimeric transcription factor, EWS-WT1, which consists of the transcriptional activation domain of the Ewing's sarcoma (EWS) protein and the DNA binding domain of the Wilms' tumor 1 (WT1) protein. One of the splice variants, EWS-WT1(-KTS) lacks three amino acid residues (Lys-Thr-Ser) in the DNA binding domain and transforms NIH3T3 cells. Therefore, it is likely that aberrant gene expression caused by EWS-WT1(-KTS) is involved in the malignant phenotype of DSRCT. Microarray analysis of 9600 human genes revealed that a gene encoding a tetraspanin-family protein, T-cell acute lymphoblastic leukemia-associated antigen 1 (TALLA-1), was induced in EWS-WT1(-KTS)-expressing cell clones. This induction was EWS-WT1(-KTS)-specific, and more importantly, TALLA-1 protein was expressed in the three independent cases of DSRCT. Tetraspanin-family genes encode transmembrane proteins that regulate various cell processes such as cell adhesion, migration and metastasis. Our findings provide a novel insight into the malignant phenotype of DSRCT, suggesting that TALLA-1 is a useful marker for diagnosis and a potential target for the therapy of DSRCT.