Tissue microarray validation of epidermal growth factor receptor and SALL2 in synovial sarcoma with comparison to tumors of similar histology

The Sall2 transcription factor promotes cell migration regulating focal adhesion turnover and integrin β1 expression

SALL2/Sall2 is a transcription factor associated with development, neuronal differentiation, and cancer. Interestingly, SALL2/Sall2 deficiency leads to failure of the optic fissure closure and neurite outgrowth, suggesting a positive role for SALL2/Sall2 in cell migration. However, in some cancer cells, SALL2 deficiency is associated with increased cell migration. To further investigate the role of Sall2 in the cell migration process, we used immortalized Sall2 knockout (Sall2−/−) and Sall2 wild-type (Sall2+/+) mouse embryonic fibroblasts (iMEFs). Our results indicated that Sall2 positively regulates cell migration, promoting cell detachment and focal adhesions turnover. Sall2 deficiency decreased cell motility and altered focal adhesion dynamics. Accordingly, restoring Sall2 expression in the Sall2−/− iMEFs by using a doxycycline-inducible Tet-On system recovered cell migratory capabilities and focal adhesion dynamics. In addition, Sall2 promoted the autophosphorylation of Focal Adhesion Kinase (FAK) at Y397 and increased integrin β1 mRNA and its protein expression at the cell surface. We demonstrated that SALL2 increases ITGB1 promoter activity and binds to conserved SALL2-binding sites at the proximal region of the ITGB1 promoter, validated by ChIP experiments. Furthermore, the overexpression of integrin β1 or its blockade generates a cell migration phenotype similar to that of Sall2+/+ or Sall2−/− cells, respectively. Altogether, our data showed that Sall2 promotes cell migration by modulating focal adhesion dynamics, and this phenotype is associated with SALL2/Sall2-transcriptional regulation of integrin β1 expression and FAK autophosphorylation. Since deregulation of cell migration promotes congenital abnormalities, tumor formation, and spread to other tissues, our findings suggest that the SALL2/Sall2-integrin β1 axis could be relevant for those processes.

Visual Counting and Automated Image-analytic Assessment of Ki-67 and their Prognostic Value in Synovial Sarcoma

BACKGROUND

Ki-67 is a widely used proliferation marker reflecting prognosis in various tumors. However, visual assessment and scoring of Ki-67 suffers from marked inter-observer and intra-observer variability. We aimed to assess the concordance of manual counting and automated image-analytic scoring methods for Ki-67 in synovial sarcoma.

PATIENTS AND METHODS

Tissue microarrays from 34 patients with synovial sarcoma were immunostained for Ki-67 and scored both visually and with 3DHistech QuantCenter.

RESULTS

The automated assessment of Ki-67 expression was in good agreement with the visually counted Ki-67 (r _Pearson =0.96, p<0.001). In a Cox regression model automated [hazard ratio (HR)=1.047, p=0.024], but not visual (HR=1.063, p=0.053) assessment method associated high Ki-67 scores with worse overall survival.

CONCLUSION

The automated Ki-67 assessment method appears to be comparable to the visual method in synovial sarcoma and had a significant association to overall survival.

Effectiveness of 4-1BB-costimulated HER2-targeted chimeric antigen receptor T cell therapy for synovial sarcoma

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HER2-targeted/4-1BB costimulated CAR T cells recognized synovial sarcoma cells.

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HER2-targeted CAR T cells secrete interferon gamma and tumor necrosis factor alpha.

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HER2-targeted CAR T cells exert cytotoxic effects in synovial sarcoma cells.

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HER2-targeted CAR T cell therapy for chemo-refractory or relapsed synovial sarcoma.

Background

Synovial sarcoma is a rare malignant soft-tissue tumor that is prevalent in adolescents and young adults, and poor prognosis has been reported in patients with metastatic lesions. Chimeric antigen receptor (CAR) T-cell therapy is an emerging novel therapy for solid tumors; however, its application in synovial sarcoma has not yet been explored.

Methods

A novel human epidermal growth factor receptor 2 (HER2)-targeted CAR containing scFv-FRP5, CD8α hinge and transmembrane domains as well as 4-1BB costimulatory and CD3ζ signaling domains was developed. Three synovial sarcoma cell lines that expressed the fusion transcript SS18-SSX1/2/4 were used in the study. Cytokine secretion assay, cytotoxicity assay, and real-time cell analysis experiments were conducted to confirm the function of T cells transduced with the CAR gene.

Results

High cell-surface expression of HER2 was observed in all the cell lines. HER2-targeted/4-1BB-costimulated CAR T cells specifically recognized the synovial sarcoma cells, secreted interferon gamma and tumor necrosis factor alpha, and exerted cytotoxic effects in these cells.

Conclusion

To the best of our knowledge, this is the first study to indicate that HER2-targeted CAR T cells are directly effective against molecularly defined synovial sarcoma cells. Furthermore, our findings might set the basis for developing improved CAR T cell-based therapies for chemo-refractory or relapsed synovial sarcoma.

Establishment of an Academic Tissue Microarray Platform as a Tool for Soft Tissue Sarcoma Research

Soft tissue sarcoma (STS) is a heterogeneous family of rare mesenchymal tumors, characterized by histopathological and molecular diversity. Tissue microarray (TMA) is a tool that allows performing research in orphan diseases in a more efficient and cost-effective way. TMAs are paraffin blocks consisting of multiple small representative tissue cores from biological samples, for example, from multiple donors, diverse sites of disease, or multiple different diseases. In 2015, we began constructing TMAs using archival tumor material from STS patients. Specimens were well annotated in terms of histopathological diagnosis, treatment, and clinical follow-up of the tissue donors. Each TMA block contains duplicate or triplicate 1.0–1.5 mm tissue cores from representative tumor areas selected by sarcoma pathologists. The construction of TMAs was performed with TMA Grand Master (3DHistech). So far, we have established disease-specific TMAs from 7 STS subtypes: gastrointestinal stromal tumor (72 cases included in the array), alveolar soft part sarcoma (n = 12 + 47), clear cell sarcoma (n = 22 + 32), leiomyosarcoma (n = 55), liposarcoma (n = 42), inflammatory myofibroblastic tumor (n = 12 + 21), and alveolar rhabdomyosarcoma (n = 24). We also constructed a multisarcoma TMA covering a representative number of important histopathological subtypes on arrays for screening purposes, namely, angiosarcoma, dedifferentiated liposarcoma, pleomorphic liposarcoma, and myxoid liposarcoma, leiomyosarcoma, malignant peripheral nerve sheath tumor, myxofibrosarcoma, rhabdomyosarcoma, synovial sarcoma, and undifferentiated pleomorphic sarcoma, with 7–11 individual cases per subtype. We are currently expanding the list of TMAs with additional sarcoma entities, considering the heterogeneity of this family of tumors. Our extensive STS TMA platform is suitable for rapid and cost-effective morphological, immunohistochemical, and molecular characterization of the tumor as well as for the identification of potential novel diagnostic markers and drug targets. It is readily available for collaborative projects with research partners.

Synovial Sarcoma: A Complex Disease with Multifaceted Signaling and Epigenetic Landscapes

PURPOSE OF REVIEW

Aside from a characteristic SS18-SSX translocation identified in almost all cases, no genetic anomalies have been reliably isolated yet to drive the pathogenesis of synovial sarcoma. In the following review, we explore the structural units of wild-type SS18 and SSX, particularly as they relate to the transcriptional alterations and cellular pathway changes imposed by SS18-SSX.

RECENT FINDINGS

Native SS18 and SSX contribute recognizable domains to the SS18-SSX chimeric proteins, which inflict transcriptional and epigenetic changes through selective protein interactions involving the SWI/SNF and Polycomb chromatin remodeling complexes. Multiple oncogenic and developmental pathways become altered, collectively reprogramming the cellular origin of synovial sarcoma and promoting its malignant transformation. Synovial sarcoma is characterized by complex epigenetic and signaling landscapes. Identifying the operational pathways and concomitant genetic changes induced by SS18-SSX fusions could help develop tailored therapeutic strategies to ultimately improve disease control and patient survivorship.

Tumor-associated macrophages and macrophage-related immune checkpoint expression in sarcomas

Early trials for immune checkpoint inhibitors in sarcomas have delivered mixed results, and efforts to improve outcomes now look to combinatorial strategies with novel immunotherapeutics, including some that target macrophages. To enhance our understanding of the sarcoma immune landscape, we quantified and characterized tumor-associated macrophage infiltration and expression of the targetable macrophage-related immune checkpoint CD47/SIRPα across sarcoma types. We surveyed immunohistochemical expression of CD68, CD163, CD47, and SIRPα in tissue microarrays of 1242 sarcoma specimens (spanning 24 types). Non-translocation sarcomas, particularly undifferentiated pleomorphic sarcoma and dedifferentiated liposarcoma, had significantly higher counts of both CD68+ and CD163+ macrophages than translocation-associated sarcomas. Across nearly all sarcoma types, macrophages outnumbered tumor-infiltrating lymphocytes and CD163+ (M2-like) macrophages outnumbered CD68+ (M1-like) macrophages. These findings were supported by data from The Cancer Genome Atlas, which showed a correlation between increasing macrophage contributions to immune infiltration and several measures of DNA damage. CD47 expression was bimodal, with most cases showing either 0% or >90% tumor cell staining, and the highest CD47 scores were observed in chordoma, angiosarcoma, and pleomorphic liposarcoma. SIRPα scores correlated well with CD47 expression. Given the predominance of macrophage infiltrates over tumor-infiltrating lymphocytes, the bias toward M2-like (immunosuppressive) macrophage polarization, and the generally high scores for CD47 and SIRPα, macrophage-focused immunomodulatory agents, such as CD47 or IDO-1 inhibitors, may be particularly worthwhile to pursue in sarcoma patients, alone or in combination with lymphocyte-focused agents.

Expression of lymphocyte immunoregulatory biomarkers in bone and soft-tissue sarcomas

Despite advances in our understanding of the underlying molecular drivers of sarcomas, few treatments are available with proven benefit for advanced metastatic sarcomas. Immunotherapy has value in this setting for some types of cancers, but sarcomas, with their multiplicity of rare types, have not been characterized in detail for their expression of targetable immune biomarkers. This study provides the most systematic evaluation to date of tumor-infiltrating lymphocytes and immune checkpoint biomarker expression in sarcomas. We examined by morphology and immunohistochemistry 1072 sarcoma specimens representing 22 types, in addition to 236 benign bone and soft-tissue tumors. Genomically-complex sarcoma types-those driven by mutations and/or copy-number alterations-had much higher numbers of tumor-infiltrating lymphocytes than translocation-associated sarcomas. Prior exposure to radiotherapy was associated with increased immune infiltrates. Higher lymphocytic infiltration was associated with better overall survival among the non-translocation-associated sarcomas. Expression of PD-1 and CD56 were associated with worse overall survival. LAG-3 and TIM-3, two emerging immune checkpoints, were frequently expressed in most sarcoma types. Indeed, most cases positive for PD-(L)1 coexpressed one or both of these novel biomarkers, providing a potential rationale in support for trials targeting LAG-3 and/or TIM-3 in conjunction with PD-1 inhibition.

SALL2 Is a Novel Prognostic Methylation Marker in Patients with Oral Squamous Carcinomas: Associations with SALL1 and SALL3 Methylation Status

Staging and pathological grading systems are convenient, but imperfect predictors of recurrence of head and neck squamous cell carcinoma. Therefore, to identify potential alternative prognostic markers, we investigated the methylation status of the promoter of Sal-like protein 2 (SALL2). SALL2 mRNA expression was absent in 8/9 (88.9%) University of Michigan squamous cell carcinoma cell lines, whereas two nonmalignant cell lines had stable expression. The normalized methylation value of SALL2 in cancer cell lines was significantly higher than in normal cell lines. SALL2 methylation found in 74 of 233 (31.8%) tumor specimens was correlated with the methylation status of both SALL1 and SALL3. SALL2 methylation was not associated with any difference in disease-free survival (DFS). Therefore, the presence of SALL2 methylation was statistically correlated with a decrease in DFS in patients with oral cancer (log-rank test, p = 0.032). Furthermore, it was associated with disease recurrence in 36.2% of oral cancer cases, with an odds ratio of 2.922 (95% confidence interval = 1.198-7.130; p = 0.018) by multivariate Cox proportional hazard regression analysis. This study suggests that cytosine-phosphate- guanosine (CpG) hypermethylation is a likely mechanism of SALL2 inactivation and supports the hypothesis that SALL2 could serve as an important clinical risk assessment.

Low HIF-1α and low EGFR mRNA Expression Significantly Associate with Poor Survival in Soft Tissue Sarcoma Patients; the Proteins React Differently

In various tumors, the hypoxia inducible factor-1α (HIF-1α) and the epidermal growth factor-receptor (EGFR) have an impact on survival. Nevertheless, the prognostic impact of both markers for soft tissue sarcoma (STS) is not well studied. We examined 114 frozen tumor samples from adult soft tissue sarcoma patients and 19 frozen normal tissue samples. The mRNA levels of HIF-1α, EGFR, and the reference gene hypoxanthine phosphoribosyltransferase (HPRT) were quantified using a multiplex qPCR technique. In addition, levels of EGFR or HIF-1α protein were determined from 74 corresponding protein samples using ELISA techniques. Our analysis showed that a low level of HIF-1α or EGFR mRNA (respectively, relative risk (RR) = 2.8; p = 0.001 and RR = 1.9; p = 0.04; multivariate Cox´s regression analysis) is significantly associated with a poor prognosis in STS patients. The combination of both mRNAs in a multivariate Cox’s regression analysis resulted in an increased risk of early tumor-specific death of patients (RR = 3.1, p = 0.003) when both mRNA levels in the tumors were low. The EGFR protein level had no association with the survival of the patient’s cohort studied, and a higher level of HIF-1α protein associated only with a trend to significance (multivariate Cox’s regression analysis) to a poor prognosis in STS patients (RR = 1.9, p = 0.09). However, patients with low levels of HIF-1α protein and a high content of EGFR protein in the tumor had a three-fold better survival compared to patients without such constellation regarding the protein level of HIF-1α and EGFR. In a bivariate two-sided Spearman’s rank correlation, a significant correlation between the expression of HIF-1α mRNA and expression of EGFR mRNA (p < 0.001) or EGFR protein (p = 0.001) was found, additionally, EGFR mRNA correlated with EGFR protein level (p < 0.001). Our results show that low levels of HIF-1α mRNA or EGFR mRNA are negative independent prognostic markers for STS patients, especially after combination of both parameters. The protein levels showed a different effect on the prognosis. In addition, our analysis suggests a possible association between HIF-1α and EGFR expression in STS.

Sall2 knockdown exacerbates palmitic acid induced dysfunction and apoptosis of pancreatic NIT-1 beta cells

Spalt-like (Sall) proteins are a class of transcription factors. The role of Sall2 in beta cells remain poorly understood. Here, we aimed to explore whether Sall2 involved in lipotoxicity-mediated dysfunction and apoptosis in pancreatic NIT-1 beta cells. Our results showed that high concentrations of palmitic acid (PA) led to impaired cell viability and decreased Sall2 expression in NIT-1 cells. Knocking down of Sall2 in NIT-1 cells resulted in increased sensitivity to lipotoxicity and caused higher rates of cell apoptosis following PA treatment. Additionally, Sall2 Knockdown impaired insulin synthesis and secretion in response to glucose. Further research indicated Sall2 knockdown attenuate antioxidant capacity and decreased expression level of Peroxiredoxin 2 in NIT-1 cells. These finding implicate that Sall2 may play a significant role in NIT-1 cell function and cell apoptosis under lipotoxic conditions. Therefore, the study of Sall2 in NIT-1 cells provided a new perspective for molecular mechanism of lipotoxicity mediating dysfunction and apoptosis of beta cells.

SALL2 represses cyclins D1 and E1 expression and restrains G1/S cell cycle transition and cancer-related phenotypes

SALL2 is a poorly characterized transcription factor that belongs to the Spalt‐like family involved in development. Mutations on SALL2 have been associated with ocular coloboma and cancer. In cancers, SALL2 is deregulated and is proposed as a tumor suppressor in ovarian cancer. SALL2 has been implicated in stemness, cell death, proliferation, and quiescence. However, mechanisms underlying roles of SALL2 related to cancer remain largely unknown. Here, we investigated the role of SALL2 in cell proliferation using mouse embryo fibroblasts (MEFs) derived from Sall2^−/− mice. Compared to Sall2^+/+ MEFs, Sall2^−/− MEFs exhibit enhanced cell proliferation and faster postmitotic progression through G1 and S phases. Accordingly, Sall2^−/− MEFs exhibit higher mRNA and protein levels of cyclins D1 and E1. Chromatin immunoprecipitation and promoter reporter assays showed that SALL2 binds and represses CCND1 and CCNE1 promoters, identifying a novel mechanism by which SALL2 may control cell cycle. In addition, the analysis of tissues from Sall2^+/+ and Sall2^−/− mice confirmed the inverse correlation between expression of SALL2 and G1‐S cyclins. Consistent with an antiproliferative function of SALL2, immortalized Sall2^−/− MEFs showed enhanced growth rate, foci formation, and anchorage‐independent growth, confirming tumor suppressor properties for SALL2. Finally, cancer data analyses show negative correlations between SALL2 and G1‐S cyclins’ mRNA levels in several cancers. Altogether, our results demonstrated that SALL2 is a negative regulator of cell proliferation, an effect mediated in part by repression of G1‐S cyclins’ expression. Our results have implications for the understanding and significance of SALL2 role under physiological and pathological conditions.

A Trichostatin A (TSA)/Sp1-mediated mechanism for the regulation of SALL2 tumor suppressor in Jurkat T cells

SALL2 is a transcription factor involved in development and disease. Deregulation of SALL2 has been associated with cancer, suggesting that it plays a role in the disease. However, how SALL2 is regulated and why is deregulated in cancer remain poorly understood. We previously showed that the p53 tumor suppressor represses SALL2 under acute genotoxic stress. Here, we investigated the effect of Histone Deacetylase Inhibitor (HDACi) Trichostatin A (TSA), and involvement of Sp1 on expression and function of SALL2 in Jurkat T cells. We show that SALL2 mRNA and protein levels were enhanced under TSA treatment. Both, TSA and ectopic expression of Sp1 transactivated the SALL2 P2 promoter. This transactivation effect was blocked by the Sp1-binding inhibitor mithramycin A. Sp1 bound in vitro and in vivo to the proximal region of the P2 promoter. TSA induced Sp1 binding to the P2 promoter, which correlated with dynamic changes on H4 acetylation and concomitant recruitment of p300 or HDAC1 in a mutually exclusive manner. Our results suggest that TSA-induced Sp1-Lys703 acetylation contributes to the transcriptional activation of the P2 promoter. Finally, using a CRISPR/Cas9 SALL2-KO Jurkat-T cell model and gain of function experiments, we demonstrated that SALL2 upregulation is required for TSA-mediated cell death. Thus, our study identified Sp1 as a novel transcriptional regulator of SALL2, and proposes a novel epigenetic mechanism for SALL2 regulation in Jurkat-T cells. Altogether, our data support SALL2 function as a tumor suppressor, and SALL2 involvement in cell death response to HDACi.

A review of soft-tissue sarcomas: translation of biological advances into treatment measures

Soft-tissue sarcomas are rare malignant tumors arising from connective tissues and have an overall incidence of about five per 100,000 per year. While this diverse family of malignancies comprises over 100 histological subtypes and many molecular aberrations are prevalent within specific sarcomas, very few are therapeutically targeted. Instead of utilizing molecular signatures, first-line sarcoma treatment options are still limited to traditional surgery and chemotherapy, and many of the latter remain largely ineffective and are plagued by disease resistance. Currently, the mechanism of sarcoma oncogenesis remains largely unknown, thus necessitating a better understanding of pathogenesis. Although substantial progress has not occurred with molecularly targeted therapies over the past 30 years, increased knowledge about sarcoma biology could lead to new and more effective treatment strategies to move the field forward. Here, we discuss biological advances in the core molecular determinants in some of the most common soft-tissue sarcomas - liposarcoma, angiosarcoma, leiomyosarcoma, rhabdomyosarcoma, Ewing's sarcoma, and synovial sarcoma - with an emphasis on emerging genomic and molecular pathway targets and immunotherapeutic treatment strategies to combat this confounding disease.

The SS18-SSX Oncoprotein Hijacks KDM2B-PRC1.1 to Drive Synovial Sarcoma

Synovial sarcoma is an aggressive cancer invariably associated with a chromosomal translocation involving genes encoding the SWI-SNF complex component SS18 and an SSX (SSX1 or SSX2) transcriptional repressor. Using functional genomics, we identify KDM2B, a histone demethylase and component of a non-canonical polycomb repressive complex 1 (PRC1.1), as selectively required for sustaining synovial sarcoma cell transformation. SS18-SSX1 physically interacts with PRC1.1 and co-associates with SWI/SNF and KDM2B complexes on unmethylated CpG islands. Via KDM2B, SS18-SSX1 binds and aberrantly activates expression of developmentally regulated genes otherwise targets of polycomb-mediated repression, which is restored upon KDM2B depletion, leading to irreversible mesenchymal differentiation. Thus, SS18-SSX1 deregulates developmental programs to drive transformation by hijacking a transcriptional repressive complex to aberrantly activate gene expression.

EGFR is involved in dermatofibrosarcoma protuberans progression to high grade sarcoma

Dermatofibrosarcoma protuberans (DFSP), amounting to 6% of all soft tissue sarcomas, has a slow growth rate, contrasting with a likelihood for local recurrence and a 10-20% evolution to higher-grade sarcoma, or "transformed DFSP" (DFSP-T). At molecular level, the characteristic COL1A1-PDGFB rearrangement, leading to sustained PDGFR signaling, is not linked to the evolutive potential. Here, we studied EGFR, another tyrosine kinase receptor, using laser-microdissection to select the different histologic components of DFSP (DFSP center, DFSP infiltrative periphery, DFSP-T higher-grade sarcoma), in 22 patients followed over 3 to 156 months. EGFR protein and mRNA were expressed in 13/22 patients with DFSP or DFSP-T, and increased with tumor progression, both in microdissected areas of higher-grade sarcomas and in microdissected areas of local extension. No cancer-associated EGFR gene mutation or copy-number variation, nor any KRAS, BRAF, NRAS hotspot mutations were found in any microdissected area. Among epithelial-mesenchymal transition factors tested, SNAIL 1/2 had the same expression pattern as EGFR while ZEB1/2 or TWIST1/2 did not. Using a proteome profiler phospho-kinase array on 3 DFSP and 3 DFSP-T cryopreserved tissue samples, EGFR phosphorylation was detected in each case. Among EGFR downstream pathways, we found positive correlations between phosphorylation levels of EGFR and STAT5a/b (r = 0.87, p < 0.05) and TOR (r = 0.95, p < 0.01), but not ERK in the MAPK pathway (r = -0.18, p > 0.70). We thus demonstrated that in DFSP evolution to high grade sarcoma, EGFR and SNAIL were involved, with EGFR activation and signaling through TOR and STAT5a/b downstream effectors, which could lead on to new therapies for advanced DFSP.

Effect of siRNA-silencing of SALL2 gene on growth, migration and invasion of human ovarian carcinoma A2780 cells

Background

The role of Spalt-like gene-2 (SALL2) in tumorigenesis remains incompletely elucidated. This study investigated the effects of SALL2 on human ovarian carcinoma (OC) A2780 cells and the probable mechanism.

Methods

Expression of SALL2 in human OC cell lines were detected by reverse transcription PCR (RT-PCR) and Western blot analysis. A2780 cells were transfected with small-interfering ribonucleic acid (siRNA) to silence SALL2. SALL2 expression was detected by RT-PCR, Western blot analysis and immunofluorescence assay. Cell proliferation was measured by CCK-8 assay and flow cytometry (FCM). Apoptosis was measured by FCM. Cell migration was detected by real-time cell analysis. Cell invasion was detected by transwell assay. mRNA expression of p21 was detected by quantitative real-time PCR. Western blot analysis was used to determine the expression of matrix metalloproteinase (MMP)2, MMP9, protein kinase B (PKB, also called Akt), and phosphorylated-Akt (p-Akt).

Results

SALL2 was expressed in six OC cell lines, and the expression was the highest in A2780 cells. Compared with that in the Scramble group, SALL2 expression in A2780 was downregulated after transfection with siRNA-2 and siRNA-3 for 48 h. Compared with that in the Scramble group, proliferation of A2780 cells in the siRNA-2 group increased after transfection for 24, 48 and 72 h. In the siRNA-2 group, the proportion of A2780 cells decreased in the G0/G1 phase, and cell apoptosis decreased after transfection for 48 h. Compared with that in the Scramble group, the cell migration and invasion abilities of A2780 cells increased. Compared with that in the Scramble group, p21 mRNA expression in A2780 cells decreased after transfection with siRNA2. When SALL2 was silenced, the expression of MMP2/9 and p-Akt in A2780 cells increased. Furthermore, the PI3K inhibitor LY294002 could effectively reversed SALL2 siRNA-induced phosphorylation of Akt, migration and invasion of A2780 cells.

Conclusion

Transient silencing of SALL2 promotes cell proliferation, migration, and invasion, and inhibits apoptosis of A2780 cells. In SALL2 siRNA-silenced cells, p21 expression was decreased. SALL2 knockdown by siRNA induces the migration and invasion of A2780 cells; this phenomenon is possibly associated with the increased expression of MMP2/9 and the activation of the PI3K/Akt signalling pathway.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3843-y) contains supplementary material, which is available to authorized users.

Significance of Phosphorylated Epidermal Growth Factor Receptor and Its Signal Transducers in Human Soft Tissue Sarcoma

Previous studies have shown that total epidermal growth factor receptor (EGFR) protein is highly expressed in soft tissue sarcoma (STS). We aimed to investigate the significance of phosphorylated-EGFR (pEGFR) and its activated-downstream signal transducers in STS tissue samples. A tissue microarray comprising 87 STS samples was assessed for total EGFR, pEGFR and its phosphorylated signal transducers and expression was correlated with clinicopathlogical parameters including patient outcome. Although the expression of total EGFR was significantly associated with adverse STS histologic grade (p = 0.004) and clinical stage (p = 0.012) similar to pEGFR, phosphorylated protein kinase B (pAkt) and phosphorylated extracellular signal regulated kinase (pERK), it is not a prognostic factor for survival. By contrast, the expression of pEGFR is an independent factor for cancer specific survival, while pERK is an independent prognostic factor for both overall and cancer specific survival in STS (p < 0.05, Cox proportional hazard model and log-rank test) in addition to the recognised factors of tumour grade and clinical stage. pERK and pEGFR are new independent prognostic factors for overall and/or cancer specific survival in STS. The expression of EGFR/pEGFR, and their associated downstream signal transducers, was associated with STS progression, suggesting that EGFR downstream signalling pathways may jointly support STS cell survival.

Synovial Sarcoma: Advances in Diagnosis and Treatment Identification of New Biologic Targets to Improve Multimodal Therapy

Synovial sarcoma is a translocation-associated soft-tissue malignancy that frequently affects adolescents and young adults. It is driven by one of the fusion oncoproteins SS18-SSX1, SS18-SSX2, or rarely, SS18-SSX4. Prognosis of patients with recurrent or metastatic disease is generally poor, and newer therapeutic strategies are needed. In this review, we present recent discoveries in the pathogenesis, diagnosis, and treatment of synovial sarcoma. We discuss potential therapeutic strategies to improve clinical outcomes in this disease.

Cytokeratin-Positive Meningeal Peripheral PNET/Ewing's Sarcoma of the Cervical Spinal Cord: Diagnostic Value of Genetic Analysis

Peripheral primitive neuroectodermal tumor (PNET)/Ewing's sarcoma (ES) of the central nervous system is extremely rare and should be differentiated from central PNET and other small blue round cell tumors. We describe a case of a meningeal peripheral PNET/ES of the spinal cord in an 11 -year-old boy. Immunohistochemically, the small blue round cell tumor showed expression of epithelial markers and of CD99, thus posing an important differential diagnostic problem with a poorly differentiated synovial sarcoma. Fluorescence in situ hybridization revealed rearrangement of the EWS gene, as seen in peripheral PNET/ES. Peripheral PNET/ES does occur in the central nervous system, but its diagnosis can be extremely difficult on morphologic and immunohistochemical grounds alone. Genetic analysis plays a key role in its distinction from other small blue round cell tumors.

Loss of H3K27 tri-methylation is a diagnostic marker for malignant peripheral nerve sheath tumors and an indicator for an inferior survival

Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive sarcomas that can show overlapping features with benign neurofibromas as well as high-grade sarcomas. Additional diagnostic markers are needed to aid in this often challenging differential diagnosis. Recently mutations in two critical components of the polycomb repressor 2 (PRC2) complex, SUZ12 and EED, were reported to occur specifically in MPNSTs while such mutations are absent in neurofibromas, both in the setting of neurofibromatosis (NF) and sporadic cases. Furthermore, both SUZ12 and EED mutations in MPNSTs were associated with loss of H3K27 tri-methylation, a downstream target of PRC2. Therefore, we tested whether H3K27me3 immunohistochemistry is useful as a diagnostic and prognostic marker for MPNSTs. We performed H3K27me3 immunohistochemistry in 162 primary MPNSTs, 97 neurofibromas and 341 other tumors using tissue microarray. We observed loss of H3K27me3 in 34% (55/162) of all MPNSTs while expression was retained in all neurofibromas including atypical (n=8) and plexiform subtypes (n=24). Within other tumors we detected loss of H3K27me3 in only 7% (24/341). Surprisingly, 60% (9/15) of synovial sarcomas and 38% (3/8) of fibrosarcomatous dermatofibrosarcoma protuberans (DFSP) showed loss of H3K27 trimethylation. Only 1 out of 44 schwannomas showed loss of H3K27me3 and all 4 perineuriomas showed intact H3K27me3. Furthermore, MPNSTs with loss of H3K27 tri-methylation showed inferior survival compared with MPNSTs with intact H3K27 tri-methylation, which was validated in two independent cohorts. Our results indicate that H3K27me3 immunohistochemistry is useful as a diagnostic marker, in which loss of H3K27me3 favors MPNST above neurofibroma. However, H3K27me3 immunohistochemistry is not suitable to distinguish MPNST from its morphological mimicker synovial sarcoma or fibrosarcomatous DFSP. Since loss of H3K27 tri-methylation was related to poorer survival in MPNST, chromatin modification mediated by this specific histone seems to orchestrate more aggressive tumour biology.

Diffuse high intensity PD-L1 staining in thymic epithelial tumors

INTRODUCTION

Blockade of the immune checkpoint programmed death receptor ligand-1 (PD-L1)/PD-1 pathway has well-established clinical activity across many tumor types. PD-L1 protein expression by immunohistochemistry is emerging as a predictive biomarker of response to these therapies. Here, we examine PD-L1 expression in a thymic epithelial tumor (TET) tissue microarray (TMA).

METHODS

The TMA contained 69 TETs and 17 thymic controls, with each case represented by triplicate cores. The TMA was stained with rabbit monoclonal antibody (clone 15; Sino Biological, Beijing, China) to human PD-L1. PD-L1 staining was scored based on intensity as follows: 0 = none, 1 = equivocal/uninterpretable, 2 = weak, and 3 = intermediate-strong. Those cases with all cores scoring three in the epithelial component were categorized as PD-L1 high and the remaining as PD-L1 low.

RESULTS

PD-L1 high scores were more frequent in TETs than in controls (68.1% versus 17.6%; p = 0.0036). PD-L1 scores and histology were significantly correlated, with higher intensity staining in World Health Organization (WHO). B2/B3/C TETs. Only 14.8% of TETs had PD-L1 staining of associated lymphocytes. In an adjusted analysis (age/sex), PD-L1 high TETs had a significantly worse overall survival (hazard ratio: 5.40, 95% confidence interval: 1.13-25.89; p = 0.035) and a trend for worse event-free survival (hazard ratio: 2.94, 95% confidence interval: 0.94-9.24; p = 0.064).

CONCLUSIONS

PD-L1 expression was present in all cases of TETs within the epithelial component but only in a minority in the lymphocytic component. TETs stained more intensely for PD-L1 than in controls, and PD-L1 high TETs were associated with more aggressive histology and worse prognosis. This study lends rationale to a clinical trial with anti-PD-1/PD-L1 therapy in this rare tumor type.

Sall2 is required for proapoptotic Noxa expression and genotoxic stress-induced apoptosis by doxorubicin

The Sall2 transcription factor is deregulated in several cancers; however, little is known about its cellular functions, including its target genes. Recently, we demonstrated that p53 directly regulates Sall2 expression under genotoxic stress. Here, we investigated the role of Sall2 in the context of cellular response to genotoxic stress. In addition, we further examined the Sall2-p53 relationship during genotoxic stress in primary mouse embryo fibroblasts (MEFs), which are derived from Sall2 knockout mice separately, or in combination with the p53ERTAM knock-in mice. We found that the levels of Sall2 mRNA and protein are dynamically modulated in response to doxorubicin. At early times of stress, Sall2 is downregulated, but increases under extension of the stress in a p53-independent manner. Based on caspase-3/7 activities, expression of cleaved poly (ADP-ribose) polymerase, expression of cleaved caspase-3 and induction of proapoptotic proteins, Sall2 expression was correlated with cellular apoptosis. Consequently, Sall2-/- MEFs have decreased apoptosis, which relates with increased cell viability in response to doxorubicin. Importantly, Sall2 was required for apoptosis even in the presence of fully activated p53. Searching for putative Sall2 targets that could mediate its role in apoptosis, we identified proapoptotic NOXA/PMAIP1 (phorbol-12-myristate-13-acetate-induced protein 1). We demonstrated that Sall2 positively regulates Noxa promoter activity. Conserved putative Sall2-binding sites at the NOXA promoter were validated in vitro by electrophoretic mobility shift assay and in vivo by ChIP experiments, identifying NOXA as a novel Sall2 target. In agreement, induction of Noxa protein and mRNA in response to doxorubicin was significantly decreased in Sall2-/- MEFs. In addition, studies in leukemia Jurkat T cells support the existence of the Sall2/Noxa axis, and the significance of this axis on the apoptotic response to doxorubicin in cancer cells. Our study highlights the relevance of Sall2 in the apoptotic response to extended genotoxic stress, which is important for understanding its role in normal physiology and disease.

NY-ESO-1 (CTAG1B) expression in mesenchymal tumors

New York esophageal squamous cell carcinoma 1 (NY-ESO-1, CTAG1B) is a cancer-testis antigen and currently a focus of several targeted immunotherapeutic strategies. We performed a large-scale immunohistochemical expression study of NY-ESO-1 using tissue microarrays of mesenchymal tumors from three institutions in an international collaboration. A total of 1132 intermediate and malignant and 175 benign mesenchymal lesions were enrolled in this study. Immunohistochemical staining was performed on tissue microarrays using a monoclonal antibody for NY-ESO-1. Among mesenchymal tumors, myxoid liposarcomas showed the highest positivity for NY-ESO-1 (88%), followed by synovial sarcomas (49%), myxofibrosarcomas (35%), and conventional chondrosarcomas (28%). Positivity of NY-ESO-1 in the remaining mesenchymal tumors was consistently low, and no immunoreactivity was observed in benign mesenchymal lesions. On the basis of these findings, nearly 90% of myxoid liposarcomas, as well as a significant proportion of synovial sarcomas, myxofibrosarcomas, and conventional chondrosarcomas are good candidates for immunotherapy targeting NY-ESO-1.

Synovial sarcoma: recent discoveries as a roadmap to new avenues for therapy

Oncogenesis in synovial sarcoma is driven by the chromosomal translocation t(X,18; p11,q11), which generates an in-frame fusion of the SWI/SNF subunit SS18 to the C-terminal repression domains of SSX1 or SSX2. Proteomic studies have identified an integral role of SS18-SSX in the SWI/SNF complex, and provide new evidence for mistargeting of polycomb repression in synovial sarcoma. Two recent in vivo studies are highlighted, providing additional support for the importance of WNT signaling in synovial sarcoma: One used a conditional mouse model in which knockout of β-catenin prevents tumor formation, and the other used a small-molecule inhibitor of β-catenin in xenograft models.

SIGNIFICANCE

Synovial sarcoma appears to arise from still poorly characterized immature mesenchymal progenitor cells through the action of its primary oncogenic driver, the SS18-SSX fusion gene, which encodes a multifaceted disruptor of epigenetic control. The effects of SS18-SSX on polycomb-mediated gene repression and SWI/SNF chromatin remodeling have recently come into focus and may offer new insights into the basic function of these processes. A central role for deregulation of WNT-β-catenin signaling in synovial sarcoma has also been strengthened by recent in vivo studies. These new insights into the the biology of synovial sarcoma are guiding novel preclinical and clinical studies in this aggressive cancer.

Annotation of human cancers with EGFR signaling-associated protein complexes using proximity ligation assays

Strategies to measure functional signaling-associated protein complexes have the potential to augment current molecular biomarker assays, such as genotyping and expression profiling, used to annotate diseases. Aberrant activation of epidermal growth factor receptor (EGFR) signaling contributes to diverse cancers. We used a proximity ligation assay (PLA) to detect EGFR in a complex with growth factor receptor-bound protein 2 (GRB2), the major signaling adaptor for EGFR. We used multiple lung cancer cell lines to develop and characterize EGFR:GRB2 PLA and correlated this assay with established biochemical measures of EGFR signaling. In a panel of patient-derived xenografts in mice, the intensity of EGFR:GRB2 PLA correlated with the reduction in tumor size in response to the EGFR inhibitor cetuximab. In tumor biopsies from three cohorts of lung cancer patients, positive EGFR:GRB2 PLA was observed in patients with and without EGFR mutations, and the intensity of EGFR:GRB2 PLA was predictive of overall survival in an EGFR inhibitor-treated cohort. Thus, we established the feasibility of using PLA to measure EGFR signaling-associated protein complexes in patient-based materials, suggesting the potential for similar assays for a broader array of receptor tyrosine kinases and other key signaling molecules.

Molecular profiling of childhood cancer: Biomarkers and novel therapies

BACKGROUND

Technological advances including high-throughput sequencing have identified numerous tumor-specific genetic changes in pediatric and adolescent cancers that can be exploited as targets for novel therapies.

SCOPE OF REVIEW

This review provides a detailed overview of recent advances in the application of target-specific therapies for childhood cancers, either as single agents or in combination with other therapies. The review summarizes preclinical evidence on which clinical trials are based, early phase clinical trial results, and the incorporation of predictive biomarkers into clinical practice, according to cancer type.

MAJOR CONCLUSIONS

There is growing evidence that molecularly targeted therapies can valuably add to the arsenal available for treating childhood cancers, particularly when used in combination with other therapies. Nonetheless the introduction of molecularly targeted agents into practice remains challenging, due to the use of unselected populations in some clinical trials, inadequate methods to evaluate efficacy, and the need for improved preclinical models to both evaluate dosing and safety of combination therapies.

GENERAL SIGNIFICANCE

The increasing recognition of the heterogeneity of molecular causes of cancer favors the continued development of molecularly targeted agents, and their transfer to pediatric and adolescent populations.

Myxoinflammatory fibroblastic sarcoma: a clinicopathologic analysis of 104 cases, with emphasis on predictors of outcome

In this study, we examine the clinicopathologic features of 104 cases of myxoinflammatory fibroblastic sarcoma (MIFS), a low-grade, inflammatory fibromyxoid tumor with a predilection to distal extremity soft tissue, and attempt to identify factors predictive of aggressive behavior. The study cohort consisted of 49 male and 55 female patients ranging in age from 17 to 83 (mean, 42; median, 39) years. The tumor arose primarily on the dorsal aspect of the distal extremities as a solitary and usually painless mass. Tumors ranged in size from 0.5 to 15 (mean, 3.2; median; 2.4) cm. Microscopically, tumors consisted of variably cellular and inflamed fibromyxoid tissue growing as a lobulated mass or as multiple nodules within subcutaneous tissue or along tendinofascial planes. Tumor cells ranged from plump spindled to more epithelioid cells with enlarged, vesicular nuclei. Characteristic of the process was a strikingly bizarre cell with an inclusion body-like nucleolus (85% of cases) and/or a smudgy hyperchromatic nucleus (51%) present in all but 7 cases. The mitotic rate per 50 high-power field ranged from 0 to 13 (mean, 2,9; median, 2) mitoses. Twenty-two tumors demonstrated 1 or more of the following atypical features: (1) foci with complex sarcoma-like vasculature; (2) hypercellular areas; and (3) increased mitotic activity or atypical mitotic figures. Immunohistochemically, tumor cells demonstrated immunoreactivity for vimentin (100%), D2-40 (86%), CD34 (50%), keratin(s) (33%), CD68 (27%), actin(s) (26%), desmin (9%), S-100 protein (7%), and epithelial membrane antigen (6%). Thirty of 59 patients (51%) with follow-up data suffered (at least) 1 local recurrence, and 1 patient developed metastatic disease after multiple local recurrences. Completeness of initial surgical excision was the only clinicopathologic parameter that statistically correlated with a lower incidence of recurrence (P=0.004). Histologically atypical MIFS recurred more often than conventional tumors (67% vs. 47%), but the difference was not statistically significant (P=0.35). Our study shows that histologic features often associated with more aggressive sarcomas do not substantially impact the morbidity of MIFS, and complete surgical excision provides the best chance for disease-free survival.

Integrative DNA methylation and gene expression analysis in high-grade soft tissue sarcomas

Background

High-grade soft tissue sarcomas are a heterogeneous, complex group of aggressive malignant tumors showing mesenchymal differentiation. Recently, soft tissue sarcomas have increasingly been classified on the basis of underlying genetic alterations; however, the role of aberrant DNA methylation in these tumors is not well understood and, consequently, the usefulness of methylation-based classification is unclear.

Results

We used the Infinium HumanMethylation27 platform to profile DNA methylation in 80 primary, untreated high-grade soft tissue sarcomas, representing eight relevant subtypes, two non-neoplastic fat samples and 14 representative sarcoma cell lines. The primary samples were partitioned into seven stable clusters. A classification algorithm identified 216 CpG sites, mapping to 246 genes, showing different degrees of DNA methylation between these seven groups. The differences between the clusters were best represented by a set of eight CpG sites located in the genes SPEG, NNAT, FBLN2, PYROXD2, ZNF217, COL14A1, DMRT2 and CDKN2A. By integrating DNA methylation and mRNA expression data, we identified 27 genes showing negative and three genes showing positive correlation. Compared with non-neoplastic fat, NNAT showed DNA hypomethylation and inverse gene expression in myxoid liposarcomas, and DNA hypermethylation and inverse gene expression in dedifferentiated and pleomorphic liposarcomas. Recovery of NNAT in a hypermethylated myxoid liposarcoma cell line decreased cell migration and viability.

Conclusions

Our analysis represents the first comprehensive integration of DNA methylation and transcriptional data in primary high-grade soft tissue sarcomas. We propose novel biomarkers and genes relevant for pathogenesis, including NNAT as a potential tumor suppressor in myxoid liposarcomas.

Activating transcription factor 2 in mesenchymal tumors

Activating transcription factor 2 (ATF2) is a member of activator protein 1 superfamily, which can heterodimerize with other transcription factors regulating cell differentiation and survival. ATF2 assembles into a complex with the synovial sarcoma translocation, chromosome 18 (SS18)-synovial sarcoma, X breakpoint (SSX) fusion oncoprotein, and the transducin-like enhancer of split 1 (TLE1) corepressor, driving oncogenesis in synovial sarcoma. The fusion oncoproteins in many other translocation-associated sarcomas incorporate transcription factors from the ATF/cAMP response element binding or E26 families, which potentially form heterodimers with ATF2 to regulate transcription. ATF2 may therefore play an important role in the oncogenesis of many mesenchymal tumors, but as yet, little is known about its protein expression in patient specimens. Herein we perform immunohistochemical analyses using a validated specific antibody for ATF2 expression and intracellular localization on a cohort of 594 malignant and 207 benign mesenchymal tumors representing 47 diagnostic entities. Melanoma served as a positive control for nuclear and cytoplasmic staining. High nuclear ATF2 expression was mainly observed in translocation-associated and/or spindle cell sarcomas including synovial sarcoma, desmoplastic small round cell tumor, endometrial stromal sarcoma, gastrointestinal stromal tumor, malignant peripheral nerve sheath tumor, and solitary fibrous tumor. Cytoplasmic ATF2 expression was less frequently seen than nuclear expression in malignant mesenchymal tumors. Benign mesenchymal tumors mostly showed much lower nuclear and cytoplasmic ATF2 expression.

When tissue antigens and antibodies get along: revisiting the technical aspects of immunohistochemistry--the red, brown, and blue technique

Once focused mainly on the characterization of neoplasms, immunohistochemistry (IHC) today is used in the investigation of a broad range of disease processes with applications in diagnosis, prognostication, therapeutic decisions to tailor treatment to an individual patient, and investigations into the pathogenesis of disease. This review addresses the technical aspects of immunohistochemistry (and, to a lesser extent, immunocytochemistry) with attention to the antigen-antibody reaction, optimal fixation techniques, tissue processing considerations, antigen retrieval methods, detection systems, selection and use of an autostainer, standardization and validation of IHC tests, preparation of proper tissue and reagent controls, tissue microarrays and other high-throughput systems, quality assurance/quality control measures, interpretation of the IHC reaction, and reporting of results. It is now more important than ever, with these sophisticated applications, to standardize the entire IHC process from tissue collection through interpretation and reporting to minimize variability among laboratories and to facilitate quantification and interlaboratory comparison of IHC results.

Wild type p53 transcriptionally represses the SALL2 transcription factor under genotoxic stress

SALL2- a member of the Spalt gene family- is a poorly characterized transcription factor found deregulated in various cancers, which suggests it plays a role in the disease. We previously identified SALL2 as a novel interacting protein of neurotrophin receptors and showed that it plays a role in neuronal function, which does not necessarily explain why or how SALL2 is deregulated in cancer. Previous evidences indicate that SALL2 gene is regulated by the WT1 and AP4 transcription factors. Here, we identified SALL2 as a novel downstream target of the p53 tumor suppressor protein. Bioinformatic analysis of the SALL2 gene revealed several putative p53 half sites along the promoter region. Either overexpression of wild-type p53 or induction of the endogenous p53 by the genotoxic agent doxorubicin repressed SALL2 promoter activity in various cell lines. However R175H, R249S, and R248W p53 mutants, frequently found in the tumors of cancer patients, were unable to repress SALL2 promoter activity, suggesting that p53 specific binding to DNA is important for the regulation of SALL2. Electrophoretic mobility shift assay demonstrated binding of p53 to one of the identified p53 half sites in the Sall2 promoter, and chromatin immunoprecipitation analysis confirmed in vivo interaction of p53 with the promoter region of Sall2 containing this half site. Importantly, by using a p53ER (TAM) knockin model expressing a variant of p53 that is completely dependent on 4-hydroxy-tamoxifen for its activity, we show that p53 activation diminished SALL2 RNA and protein levels during genotoxic cellular stress in primary mouse embryo fibroblasts (MEFs) and radiosensitive tissues in vivo. Thus, our finding indicates that p53 represses SALL2 expression in a context-specific manner, adding knowledge to the understanding of SALL2 gene regulation, and to a potential mechanism for its deregulation in cancer.

Searching for molecular targets in sarcoma

Sarcoma are about 1% of cancers. Within that 1% are widely varied tumors now divided into types and subtypes. Sarcoma occur in patients of all ages with frequency spread evenly over the human age range. Although the specific cell of origin of many sarcoma remains unclear, sarcoma are all tumors of mesenchymal origin. The mesenchymal stem cell, a pluripotent cell, which gives rise to varied differentiated cells including osteocytes, adipocytes, chondrocytes, muscle cells, fibroblasts, neural cells and stromal cells, is the most likely ultimate cell of origin for sarcoma. When mesenchymal stem cell genetics go awry and malignant transformation occurs sarcoma including osteosarcoma, Ewing's sarcoma, chondrosarcoma, rhabdomyosarcoma, synovial sarcoma fibrosarcoma, liposarcoma and many others can initiate. Our knowledge of sarcoma genetics is increasing rapidly. Two general groups, sarcoma arising from chromosomal translocations and sarcoma with very complex genetics, can be identified. Genes that are frequently mutated in sarcoma include TP53, NF1, PIK3CA, HDAC1, IDH1 and 2, KDR, KIT and MED12. Genes that are frequently amplified in sarcoma include CDK4, YEATS4, HMGA2, MDM2, JUN, DNM3, FLT4, MYCN, MAP3K5, GLI1 and the microRNAs miR-214 and miR-199a2. Genes that are upregulated in sarcoma include MUC4, CD24, FOXL1, ANGPTL2, HIF1α, MDK, cMET, TIMP-2, PRL, PCSK1, IGFR-1, TIE1, KDR, TEK, FLT1 and several microRNAs. While some alterations occur in specific subtypes of sarcoma, others cross several sarcoma types. Discovering and developing new therapeutic approaches for these relentless diseases is critical. The detailed knowledge of sarcoma genetics may allow development of sarcoma subtype-targeted therapeutics.

Histone deacetylase 1 and 2 in mesenchymal tumors

Histone deacetylases (HDACs) have a critical role in epigenetic gene silencing, rendering a compact chromatin structure by removing acetyl groups from lysine residues within the tails of core histones, thereby repressing gene expression. Epigenetic transcriptional dysregulation is an important oncogenic mechanism in some sarcomas associated with translocations, for which antitumor activity by HDAC inhibitors has been shown in preclinical studies. Nevertheless, the expression of the protein targets of these drugs has not yet been broadly surveyed in this neoplasia. In this study, we assess the expression of HDAC1 and 2 by immunohistochemistry in a tissue microarray series of 1332 cases, representing 44 categories of malignant and borderline mesenchymal tumors. HDAC2 was the more highly expressed isoform, and was more strongly expressed in translocation-associated sarcomas than in other mesenchymal tumors or normal tissues. HDAC1, in contrast, displayed lower expression in translocation-associated sarcomas than in other mesenchymal tumors or in normal tissues. These results indicate that HDAC1 and HDAC2 are differentially expressed in mesenchymal neoplasms, and suggest that HDAC2 is the isoform more likely contributing to the pathogenesis of many translocation-associated sarcomas and to their response to HDAC inhibitors.

Human papillomavirus type 16 E6 inhibits p21(WAF1) transcription independently of p53 by inactivating p150(Sal2)

HPV16 E6 deregulates G1/S cell cycle progression through p53 degradation preventing transcription of the CDK inhibitor p21(WAF1). However, additional mechanisms independent of p53 inactivation appear to exist. Here, we report that HPV16 E6 targets the cellular factor p150(Sal2), which positively regulates p21(WAF1) transcription. HPV16 E6 associates with p150(Sal2), inducing its functional inhibition by preventing its binding to cis elements on the p21(WAF1) promoter. A HPV16 E6 mutant, L110Q, which was unable to bind p150(Sal2), did not affect the ability of the cellular protein to bind p21(WAF1) promoter, underlining the linkage between these events. These data describe a novel mechanism by which HPV16 E6 induces cell cycle deregulation with a p53-independent pathway. The viral oncoprotein targets p150(Sal2), a positive transcription regulator of p21(WAF1) gene, preventing G1/S arrest and allowing cellular proliferation and efficient viral DNA replication.

X-linked inhibitor of apoptosis positive nuclear labeling: a new independent prognostic biomarker of breast invasive ductal carcinoma

BACKGROUND

It's well recognized that X-linked inhibitor of apoptosis (XIAP) was the most potent caspase inhibitor and second mitochondria-derived activator of caspase (Smac) was the antagonist of XIAP. Experiments in vitro identified that down regulation of XIAP expression or applying Smac mimics could sensitize breast cancer cells to chemotherapeutics and promote apoptosis. However, expression status and biologic or prognostic significance of XIAP/Smac in breast invasive ductal carcinoma (IDC) were not clear. The present study aimed to investigate relationship among expression status of XIAP/Smac, apoptosis index (AI), clinicopathologic parameters and prognosis in IDC.

METHODS

Immunohistochemistry and TUNEL experiment were performed to detect expression of XIAP, Smac, ER, PR, HER2 and AI in 102 cases of paraffin-embedded IDC samples respectively. Expression of XIAP/Smac were also detected in limited 8 cases of fresh IDC specimens with Western blot.

RESULTS

Positive ratio and immunoscore of XIAP was markedly higher than Smac in IDC (P<0.0001). It was noteworthy that 44 cases of IDC were positive in nuclear for XIAP, but none was for Smac. Expression status of Smac was more prevalent in HER2 positive group than negative group (P<0.0001) and AI was positively correlated with HER2 protein expression (rs=0.265, P=0.017). The present study first revealed that XIAP positive nuclear labeling (XIAP-N), but not cytoplasmic staining (XIAP-C), was the apoptotic marker correlated significantly with patients' shortened overall survival (P=0.039). Survival analysis demonstrated that XIAP-N was a new independent prognostic factor except for patient age and lymph node status.

CONCLUSION

Disturbed balance of expression between XIAP and Smac probably contributed to carcinogenesis and XIAP positive nuclear labeling was a new independent prognostic biomarker of breast IDC.

Datamining approach for automation of diagnosis of breast cancer in immunohistochemically stained tissue microarray images

Cancer of the breast is the second most common human neoplasm, accounting for approximately one quarter of all cancers in females after cervical carcinoma. Estrogen receptor (ER), Progesteron receptor and human epidermal growth factor receptor (HER-2/neu) expressions play an important role in diagnosis and prognosis of breast carcinoma. Tissue microarray (TMA) technique is a high throughput technique which provides a standardized set of images which are uniformly stained, facilitating effective automation of the evaluation of the specimen images. TMA technique is widely used to evaluate hormone expression for diagnosis of breast cancer. If one considers the time taken for each of the steps in the tissue microarray process workflow, it can be observed that the maximum amount of time is taken by the analysis step. Hence, automated analysis will significantly reduce the overall time required to complete the study. Many tools are available for automated digital acquisition of images of the spots from the microarray slide. Each of these images needs to be evaluated by a pathologist to assign a score based on the staining intensity to represent the hormone expression, to classify them into negative or positive cases. Our work aims to develop a system for automated evaluation of sets of images generated through tissue microarray technique, representing the ER expression images and HER-2/neu expression images. Our study is based on the Tissue Microarray Database portal of Stanford university at http://tma.stanford.edu/cgi-bin/cx?n=her1, which has made huge number of images available to researchers. We used 171 images corresponding to ER expression and 214 images corresponding to HER-2/neu expression of breast carcinoma. Out of the 171 images corresponding to ER expression, 104 were negative and 67 were representing positive cases. Out of the 214 images corresponding to HER-2/neu expression, 112 were negative and 102 were representing positive cases. Our method has 92.31% sensitivity and 93.18% specificity for ER expression image classification and 96.67% sensitivity and 88.24% specificity for HER-2/neu expression image classification.

EGFR-dependent and independent activation of Akt/mTOR cascade in bone and soft tissue tumors

To gain the insight into the involvement of signaling mediated by the mammalian target of rapamycin (mTOR) in the phenotype and biological profiles of tumors and tumor-like lesions of the bone and soft tissue, we analyzed the expression and phosphorylation (activation) of mTOR and its correlation with the status of upstream and downstream modulator proteins Akt, p70S6-kinase (S6K), and eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), which we refer to collectively as mTOR cassette proteins. Immunohistochemical analysis of 140 cases showed activation of Akt in 55% (61% in malignant and 27% in benign), and mTOR expression in 61% (66% in malignant and 39% in benign). The preponderance of mTOR activation was found in tumors of peripheral nerve sheath (malignant peripheral nerve sheath tumor and schwannoma), skeletal muscle origin (rhabdomyosarcoma), and in those exhibiting epithelial nature (chordoma and synovial sarcoma). Together with the result of immunoblotting analysis, it was shown that many of those particular tumors with mTOR activation exhibited activation of Akt, S6K, and 4E-BP1, suggesting the constitutive activation of the Akt/mTOR pathway. In addition, although activation of the Akt/mTOR pathway was largely independent of activation of epidermal growth factor receptor (EGFR), mutation of EGFR was frequently accompanied by constitutive activation of Akt-mTOR-S6K/4E-BP1. By clinicopathological analysis, activation of Akt correlates with statistically higher probability of metastasis. We conclude that mTOR-mediated signaling proteins function not only in the proliferation of the tumor cells, but also in the differentiation and/or maintenance of morphological phenotypes in tumors of rhabdomyoblastic and nerve sheath cell origin. Furthermore, mTOR signaling may also modulate morphogenesis of tumors exhibiting epithelial nature. Additionally, activated Akt may have a function in metastasis. Overall, these results suggest that inhibitors of mTOR cassette may be useful as novel components of combined chemotherapy for a defined subset of bone and soft tissue sarcomas.

Adaptor protein Crk induces Src-dependent activation of p38 MAPK in regulation of synovial sarcoma cell proliferation

The adaptor protein Crk mediates intracellular signaling related to cell motility and proliferation and is implicated in human tumorigenesis. The role of Crk in the growth of human sarcoma has remained unclear, however. The present study shows that Crk-induced activation of Src and subsequent signaling by p38 mitogen-activated protein kinase (MAPK) contribute to the enhanced proliferation of human synovial sarcoma cells. Depletion of Crk by RNA interference markedly inhibited proliferation of the synovial sarcoma cell lines HS-SYII, SYO-1, and Fuji as well as prevented anchorage-independent growth. Conversely, reconstitution with CrkII by authentic small interfering RNA-resistant Crk gene restored proliferation in Crk-silenced SYO-1 cells. Crk-depleted synovial sarcoma cells manifested enhanced transcriptional activity and expression of the p16(INK4A) gene, resulting in their accumulation in G(1) phase of the cell cycle. In response to hepatocyte growth factor stimulation, Crk prominently induced the tyrosine phosphorylation of Grb2-associated binder 1 through activation of Src and focal adhesion kinase, and the Src family kinase inhibitor PP2 almost completely inhibited the proliferation of SYO-1 cells. Crk also induced the phosphorylation of p38 MAPK, and SB203580, a p38 MAPK-specific inhibitor, increased expression of p16(INK4A) gene in SYO-1 cells. Furthermore, SB203580 or depletion of p38 MAPK by small interfering RNA suppressed both the phosphorylation of Akt triggered by hepatocyte growth factor and the proliferation of SYO-1 cells. These results suggest that Crk promotes proliferation of human synovial sarcoma cells through activation of Src and its downstream signaling by a novel p38 MAPK-Akt pathway, with these signaling molecules providing potent new targets for molecular therapeutics.

Validation of tissue microarray immunohistochemistry staining and interpretation in diffuse large B-cell lymphoma

Tissue microarrays (TMAs) show concordance with whole tissue sections in the immunohistochemical evaluation of tumor cells. However, potential inter-institutional variability among observers and immunohistochemical staining methods has not been fully addressed. We selected 21 cases of diffuse large B-cell lymphoma (DLBCL) to process for TMAs. Immunohistochemical stains were performed in 3 laboratories, and reviewed independently by 3 hematopathologists at the 3 institutions. Stains were scored on a 4-point scale. Statistical analyses of variation in the scoring among observers and among different institutions' stains were performed. Stains for CD3, CD10, CD20, BCL-2, BCL-6, MIB-1, and FOX-P1 revealed little variation among observers, with an average 51-82% complete agreement and 82-100% agreement +/- 1 numerical score. The rate of concordance when evaluating most stains performed in different laboratories was also relatively good, with an average of 55-72% complete agreement and 70-97% agreement +/- 1 score. However, scoring of MUM-1 and p53 stains showed wider variation, with an average of only 37 and 30% complete agreement among observers, and 11 and 45% agreement when stains from different institutions were examined. Further statistical analyses were performed to compare the observers' scoring of their own institution's stains (self-review) vs. observers' scoring of other institutions' stains (non-self). The agreement rate for the p53 stain was significantly higher when based on self-review (average 58% complete agreement) compared with an agreement rate of only 10.5% when based on a review of stains performed in another laboratory, non-self review, P < 0.01. This difference in the self- vs. non-self review was not seen when data for MUM-1 were analysed. In conclusion, most phenotypic markers used in the analysis of DLBCL can be evaluated in TMAs with adequate agreement among observers and laboratories. These include CD3, CD20, CD10, BCL-2, BCL-6, MIB-1, and FOX-P1. However, some markers, such as p53 and MUM-1, are more prone to inter-institutional variation. Variations in interpretation can be partially overcome by self-adjusted/adapt tendency, as seen with p53. Especially with newly developed markers, such as MUM-1, the development of standardized techniques for staining and interpretation is critical to reduce inter-observer variability.

Expression of insulin-like growth factor 2 in mesenchymal neoplasms

The insulin-like growth factor (IGF) system plays an important role in the growth and development of cells and has been implicated in oncogenesis and tumor progression. Gene expression profiling studies on limited numbers of specimens have shown high expression of IGF2, encoding the activating ligand for this system, in gastrointestinal stromal tumors (GISTs) and in synovial sarcomas. This data may have concrete clinical implications, as several reports exist of patients with GISTs suffering from severe hypoglycemia, a predicted effect of IGF2. Furthermore, new drugs targeting IGF signaling are entering clinical trials. The purpose of this study is to survey IGF2 expression at the protein level on a broad number of mesenchymal tumors representing all major diagnostic classes. By immunostaining tissue microarrays, results were obtained for 51 diagnostic categories of bone and soft-tissue tumors representing 1288 cases. Distinct membranous and/or cytoplasmic IGF2 immunoreactivity was assessed according to published criteria. Solitary fibrous tumors had the highest expression. Of 20 tumor types represented by more than 10 cases, synovial sarcomas, myxoid liposarcomas, GISTs, malignant peripheral nerve sheath tumors, chondrosarcomas, undifferentiated pleomorphic sarcomas (MFH), Ewing's sarcomas and tenosynovial giant cell tumors showed high levels of expression in more than 20% of cases. Of the 445 GIST cases with clinical information, those with high expression of IGF2 had a significantly worse outcome than those with low or no expression. IGF2 protein expression among mesenchymal tumors is largely consistent with gene expression studies and suggests a potential for molecular therapy targeting the IGF signaling pathway system in these neoplasms.

Gene expression profiling for the investigation of soft tissue sarcoma pathogenesis and the identification of diagnostic, prognostic, and predictive biomarkers

Soft tissue sarcomas are malignant neoplasms derived from mesenchymal tissues. Their pathogenesis is poorly understood and there are few effective treatment options for advanced disease. In the past decade, gene expression profiling has been applied to sarcomas to facilitate understanding of sarcoma pathogenesis and to identify diagnostic, prognostic, and predictive markers. In this paper, we review this body of work and discuss how gene expression profiling has led to advancements in the understanding of sarcoma pathobiology, the identification of clinically useful biomarkers, and the refinement of sarcoma classification schemes. Lastly, we conclude with a discussion of strategies to further optimize the translation of gene expression data into a greater understanding of sarcoma pathogenesis and improved clinical outcomes for sarcoma patients.