Solid pseudopapillary neoplasms of the pancreas show an interruption of the Wnt-signaling pathway and express gene products of 11q.

Solid pseudopapillary neoplasms of the pancreas almost consistently show a beta-catenin mutation activating the Wnt-signaling pathway, resulting in overexpression of cyclin D1, but not in overt malignancy of this tumor. Besides cyclin D1, a set of markers (ie FLI-1, CD56 and progesterone receptor), whose genes map to chromosome 11q, are frequently expressed in solid pseudopapillary neoplasms. Chromosome 11q is a region that is also often affected in pancreatic neuroendocrine tumors. This immunohistochemical study was undertaken to gain insights into the downstream regulation of the Wnt-signaling pathway and the significance of overexpressed gene products belonging to chromosome 11q for the tumorigenesis in solid pseudopapillary neoplasms. Fourteen solid pseudopapillary neoplasms were analyzed for the expression of cyclin-dependent kinase inhibitors p21, p27, p16 and hyperphosphorylated retinoblastoma (pRb) proteins. In an extended series of 93 solid pseudopapillary neoplasms, beta-catenin, cyclin D1, FLI-1 and CD56 expression was examined and compared with that in 22 pancreatic neuroendocrine tumors. Solid pseudopapillary neoplasms (98%) showed aberrant expression of beta-catenin with a concomitant cyclin D1 expression in 69% of the cases, but no expression of pRb (0%) was found. p27 and p21 were expressed in 100% (14/14) and 86% (12/14) of the cases, but only 2/14 (14%) were positive for p16. FLI-1 was expressed in 63% of solid pseudopapillary neoplasms, but only in 1/22 pancreatic neuroendocrine tumors (5%), cyclin D1 expression was present in 14% of the latter. We conclude that in solid pseudopapillary neoplasms the activated Wnt-signaling pathway is disrupted, and that p21 and p27 are contributing to this fact by blocking of the hyperphosphorylation of the Rb protein, thus causing the very low proliferation rate characterizing the solid pseudopapillary neoplasms. The accumulation of high expression of proteins whose genes are located on chromosome 11q is characteristic of solid pseudopapillary neoplasms, but not of pancreatic neuroendocrine tumors.     

Diagnostic utility of FLI-1 monoclonal antibody and dual-colour, break-apart probe fluorescence in situ (FISH) analysis in Ewing's sarcoma/primitive neuroectodermal tumour (EWS/PNET). A comparative study with CD99 and FLI-1 polyclonal antibodies

AIMS: To compare the sensitivity and specificity of the recently commercially available FLI-1 monoclonal (FLI-1m) antibody with the currently used antibodies [CD99 and FLI-1 polyclonal (FLI-1p)] in the diagnosis of Ewing's sarcoma/primitive neuroectodermal tumour (EWS/PNET) and to determine the diagnostic value of the EWSR1 (22q12) dual-colour, break-apart rearrangement probe fluorescence in situ hybridization (FISH) technique. MATERIALS AND METHODS: Forty-three cases of well-documented EWS/PNET and 15 non-EWS/PNET cases were retrieved from the archival files. Immunohistochemistry (IHC) for FLI-1p, FLI-1m and FISH analysis was performed. RESULTS: The most sensitive and specific test panel for the diagnosis of EWS/PNET is the combination of CD99 and FLI-1p. FISH had a very high specificity (100%) but only a moderate sensitivity (50%). CONCLUSION: The combination of CD99 and FLI-1p is the method of choice for the diagnosis of EWS/PNET. EWRS1 (22q12) dual-colour, break-apart rearrangement probe FISH should be used as a confirmatory test in addition to CD99 and FLI1-p due to its high specificity.     

FLI-1在小圆细胞肿瘤鉴别诊断中的应用

目的研究FLI-1和CD99在小圆细胞肿瘤中的表达情况,探讨二者在小圆细胞肿瘤鉴别诊断中的应用价值。方法对46例小圆细胞肿瘤进行FLI-1和CD99免疫组化标记,并结合临床与病理组织学进行对比研究。结果FLI-1在Ewing肉瘤／外周原始神经外胚叶肿瘤（EWS／PNET）中阳性表达率为90．5％（19／21）,在分化差的滑膜肉瘤、横纹肌肉瘤分别为14．3％（1／7）、22．2％（2／9）,而在嗅神经母细胞瘤和间叶软骨肉瘤均无表达。CD99在EWS／PNET中阳性表达率为95．2％（20／21）,在分化差的滑膜肉瘤、横纹肌肉瘤、嗅神经母细胞瘤和间叶软骨肉瘤分别为71．4％（5／7）、66．7％（6／9）、75．0％（3／4）和60％（3／5）。FLI-1标记在EWS／PNET的敏感性为90．5％,特异性为88％;而CD99在EWS／PNET的敏感性为95．0％,特异性为32％。FLI-1在EWS／PNET中的特异性明显高于CD99（P〈0．05）。结论FLI-1在EWS／PNET诊断中的价值优于CD99,并且可用于小圆细胞肿瘤的鉴别诊断。     

Absence of EWS/FLI1 fusion in olfactory neuroblastomas indicates these tumors do not belong to the Ewing's sarcoma family

The balanced reciprocal translocation t(11;22)(q24;q12) is a specific molecular marker for the Ewing's sarcoma family of tumors (ESFT). Based on the detection of this translocation in some olfactory neuroblastomas (ONBs), it has been proposed that ONBs also belong to the ESFT. Others have challenged this hypothesis; however, the rarity of ONBs, as well as the lack of molecular techniques that work reliably on formalin fixed tissue, have precluded the molecular analysis of a significant number of cases. We evaluated the immunophenotypic and molecular features of 17 paranasal small round neuroectodermal tumors using routinely fixed tissue. Probes localizing to 22q12 (EWS) and 11q24 (FLI-1) were used in a standard 2-color fluorescence in situ hybridization (FISH) assay to evaluate EWS/FLI1 fusion on the der(22). Sixteen tumors were mic-2 negative, whereas 1 tumor was mic-2 positive, compatible with ONB and ESFT, respectively. Thirteen of 15 ONBs could be evaluated by FISH, and all 13 were negative for the EWS/FLI1 fusion. Distinct fusion signals were identified in the single paranasal ESFT. Our findings indicate that ONBs lack the EWS/FLI1 fusion and are unrelated to the ESFT; however, true ESFTs may rarely occur as primary sinonasal tumors.     

EWS/FLI-1 oncoprotein subtypes impose different requirements for transformation and metastatic activity in a murine model

Ewing sarcoma/primitive neuroectodermal tumors (EWS/PNET) are characterized by specific chromosomal translocations most often generating a chimeric EWS/FLI-1 gene. Depending on the number of juxtaposed exons assembled, several fusion types have been described with different incidences and prognoses. To assess the impact of each fusion type on the specific phenotypic, tumorigenic, and metastatic features of EWS/PNET, we developed an amenable system using a murine mesenchymal multipotent C3H10T1/2 cell line. Upon transduction of EWS/FLI-1, cells acquired dramatic morphological changes in vitro, including a smaller size and "neurite-like" membrane elongations. Chimeric fusion proteins conferred oncogenic properties in vitro, including anchorage-independent growth and an increased rate of proliferation. Furthermore, EWS/FLI-1 expression blocked mineralization, with concomitant repression of osteoblastic genes, and induced a dramatic repression of the adipocytic differentiation program. Moreover, EWS/FLI-1 promoted an aberrant neural phenotype by the de novo expression of specific neural genes. The intramuscular injection of transduced cells led to tumor development and the induction of overt osteolytic lesions. Analogously, to what was observed in human tumors, type 2 EWS/FLI-1 cells formed primary tumors in immunodeficient mice with a higher incidence and a lower latency than cells bearing types 1 and 3 fusions. By contrast, cells expressing types 2 and 3 fusions showed specific metastatic activity with a higher number of macroscopic metastases in soft tissues and osteolytic lesions in the limbs as compared to type-1-expressing cells. Therefore, the structure of each oncoprotein strongly influenced its tumorigenicity and metastagenicity. Thus, this model provides a basis for understanding the genetic determinants involved in Ewing tumor development and metastatic activity and represents a cellular system to analyze other oncoproteins involved in human sarcomagenesis.     

Ewing sarcoma/primitive neuroectodermal tumor of the kidney: a case report. Diagnosed by immunohistochemistry and molecular analysis

BACKGROUND: Ewing sarcoma/primitive neuroectodermal tumor (EWS/PNET) of the kidney is a rare and aggressive tumor. It has a rapid clinical progression with early metastasis and death. Few cases with documented t(11;22) have been reported in the literature. CASE PRESENTATION: We report a case of EWS/PNET of the kidney in a 26-year-old woman with widespread metastasis at initial presentation. The tumor cells showed strong expression for CD99 and FLI-1 monoclonal antibodies and polyclonal antibodies and were negative for WT1 and numerous other markers. The diagnosis was subsequently confirmed by demonstrating t(11;22)(q24;q12) using cytogenetic karyotyping and fluorescence in situ hybridization. CONCLUSIONS: Due to the different prognosis and management between EWS/PNET and other primary renal neoplasms with similar morphology, a histopathologic diagnosis with extreme accuracy should be made. Cytogenetic analysis is an important supportive tool to immunohistochemistry in making the final diagnosis.     

髓母细胞瘤比较基因组杂交分析及ERBB-2异常表达的意义

目的研究髓母细胞瘤全基因组的遗传学异常,探讨癌基因的异常表达在髓母细胞瘤发病机制中的作用以及与预后的关系。方法应用比较基因组杂交（comparative genomic hybridization,CGH）技术检测14例髓母细胞瘤全基因组的遗传学改变;同时,在扩大系列的29例髓母细胞瘤中,应用荧光原位杂交（fluorescence in situ hybridization,FISH）和免疫组化染色分别检测ERBB-2在基因水平和蛋白水平的表达。结果（1）CGH结果显示,在所有14例髓母细胞瘤标本中,每一条染色体臂上都检测到了染色体的失衡（获得或丢失）,最常见的染色体异常为17q（85．7％）和7q（35．7％）的获得,以及8p（50％）、16q（28．6％）和17p（35．7％）的丢失;（2）FISH检测中,44．5％（13／29例）的肿瘤细胞有ERBB-2基因的异常表达;（3）免疫组化结果显示,37．9％（11／29例）的病例有抗体c-erbB-2的阳性表达;（4）在预后较差的16例患者中,56％（9／16例）的病例有ERBB-2的过度表达。结论CGH研究发现了髓母细胞瘤全基因组的染色体失衡。在染色体17q特异性位点上ERBB-2基因的异常改变很可能在髓母细胞瘤的发病机制中起着重要的作用,其过度表达与患者的预后密切相关。     

Molecular characterization of the t(3;9) associated with immortalization in the MCF10A cell line

The t(3;9)(p14;p21) in the MCF10A human mammary gland epithelial cell line was the single cytogenetic event that accompanied the transition from primary culture to immortalized cell line, suggesting that it is related to the development of the immortalization phenotype. To study the molecular consequences of the breakpoints in this rearrangement, we used a combination of fluorescence in situ hybridization (FISH) and array comparative genomic hybridization (CGH). The 3p14 translocation breakpoint occurs within BAC RP11-795e22, which accommodates only the TAFA1 gene, a novel cysteine-rich secreted protein thought to be involved in cytokine signaling. TAFA1 is expressed in normal breast tissue, not in MCF10A, and shows differential expression in a range of breast cancer cell lines. The 9p translocation breakpoint results in a deletion of approximately 4 megabases on the derivative chromosome 9, which includes the CDKN2A (p16) gene. Array CGH and FISH analysis demonstrated that BAC 149i22, which contains the CDKN2A/B genes, is also deleted specifically on the apparently normal copy of chromosome 9, making MCF10A null for the p16/p15 genes. The exact extent of gains and losses of chromosome regions resulting from rearrangements involving chromosomes 1q, 5q, and 8q have also been characterized using the BAC arrays.     

Ewing sarcoma/peripheral primitive neuroectodermal tumor: adult abdominal tumors with an Ewing sarcoma gene rearrangement demonstrated by fluorescence in situ hybridization in paraffin sections.

The differential diagnosis of small round cell tumors is exhaustive and requires ancillary studies. Relatively recently, fluorescence in situ hybridization (FISH) using probes for specific gene rearrangements has gained wide acceptance. This technique is particularly useful in the differential diagnosis of Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) and desmoplastic small round-cell tumor (DSRCT). In ES/PNET, the EWS gene is juxtaposed to the FLI-1 gene in 85% of cases and to the ERG gene in another 7% of cases; the EWS gene is juxtaposed to the WTI gene in DSRCT. Documentation of the EWS gene rearrangements in EWS/PNET has previously been demonstrated in frozen tissue. We report 2 unusual cases of EWS/PNET diagnosed in abdominal tumors in adults. Although the immunohistochemical results supported a diagnosis of ES/PNET, 1 case morphologically resembled DSRCT. The diagnosis in these 2 cases was confirmed by the FISH demonstration of EWS/FLI-1 gene fusion in paraffin-embedded tissue. Thus, the usefulness of FISH demonstration of an EWS gene rearrangement with these specific probes in such unusual cases is supported and is demonstrated in paraffin-embedded tissue.     

A t(1;9)(q23.3 approximately q25;q34) affecting the ABL1 gene in a biphenotypic leukemia

Recurring chromosome translocations, which are found in leukemia, can result in the inappropriate expression of oncogenes or in the formation of chimeric genes that code for structurally and functionally abnormal proteins. The chromosomal t(1;9)(q23.3 approximately q25;q34) was found in a patient with biphenotypic leukemia. Fluorescence in situ hybridization (FISH) analysis revealed that the break on chromosome 9 occurred in the ABL1 gene. The breakpoint on chromosome 1 occurred distal to the PBX1 gene at 1q23.3, as shown by FISH using BAC RP11-503N16 and RP11-403P14, which flank the PBX1 locus; hence, the ABL1 gene can be fused with another gene distal to PBX1 gene.     

Splenic marginal zone lymphomas presenting with splenomegaly and typical immunophenotype are characterized by allelic loss in 7q31-32.

Splenic marginal zone lymphoma (SMZL) is a rare non-Hodgkin's lymphoma that recently has been recognized as an entity. The first goal of this study was to identify potential chromosomal aberrations in this entity by cytogenetic analysis and comparative genomic hybridization (CGH). The second goal was to assess the frequency of 7q31-32 allelic imbalances in SMZL with primary involvement of the spleen and the typical immunophenotype (IgM+; IgD(dim); and CD5-, CD10-, and CD23-). We applied CGH and cytogenetics to 13 cases of SMZL with primary splenic involvement. By CGH, we found DNA copy number changes in 11 of 13 cases. Overall chromosomal gains were more frequent than chromosomal losses. Gains were most frequently detected for chromosome X, chromosome 3, and chromosome 18. Losses commonly involved chromosome 7 and chromosome 6.CGH and cytogenetic analysis showed a deletion in chromosome 7q31 in 4 cases. Loss of heterozygosity (LOH) analysis using three microsatellite markers located at 7q31 revealed LOH in 9 cases. Remarkably, 2 of the 4 cases that lacked a 7q31 deletion had an atypical immunophenotype because they were partially CD23 positive. The other 2 cases were not informative. The findings indicate that SMZL with primary splenic presentation and the typical IgM+, IgDdim, CD5-, CD10-, CD23- immunophenotype is characterized by the presence of deletions in chromosome 7q31-32.     

荧光原位杂交与逆转录聚合酶链反应在尤文肉瘤/原始神经外胚层肿瘤分子诊断中的应用

目的探讨运用荧光原位杂交（FISH）与逆转录聚合酶链反应（RT-PCR）检测尤文肉瘤/原始神经外胚层肿瘤（ES/PNET）石蜡包埋组织特异性染色体易位的临床应用价值.方法收集ES/PNET 10例,分离石蜡包埋组织中的肿瘤细胞,利用Vysis公司的EWSR1双色易位分离探针,间期核FISH检测EWS基因的易位.运用RT-PCR检测t（11;22）（q24;q12）和t（21;22）（q22;q12）形成的融合转录子EWS-FLI1和EWS-ERG.结果10例ES/PNET中FISH观察9例有EWS基因的易位.RT-PCR 8例检测出EWS-FLI1的表达,没有检测出EWS-ERG的表达.结论利用FISH与RT-PCR检测ES/PNET石蜡包埋组织特异性染色体易位可作为可靠的分子诊断指标;两者相比,FISH敏感性和稳定性要优于RT-PCR.