Translating gene expression into clinical care: sarcomas as a paradigm

3D Culture Modelling: An Emerging Approach for Translational Cancer Research in Sarcomas

Sarcomas are tumours of mesenchymal origin, which can arise in bone or soft tissues. They are rare but frequently quite aggressive and with a poor outcome. New approaches are needed to characterise these tumours and their resistance mechanisms to current therapies, responsible for tumour recurrence and treatment failure. This review is focused on the potential of three-dimensional (3D) in vitro models, including multicellular tumour spheroids (MCTS) and organoids, and the latest data about their utility for the study on important properties for tumour development. The use of spheroids as a particularly valuable alternative for compound high throughput screening (HTS) in different areas of cancer biology is also discussed, which enables the identification of new therapeutic opportunities in commonly resistant tumours.

The use of whole exome sequencing and murine patient derived xenografts as a method of chemosensitivity testing in sarcoma

Background

Soft tissue and bone sarcoma represent a broad spectrum of different pathology and genetic variance. Current chemotherapy regimens are derived from randomised trials and represent empirical treatment. Chemosensitivity testing and whole exome sequencing (WES) may offer personalized chemotherapy treatment based on genetic mutations.

Methods

A pilot, prospective, non-randomised control experimental study was conducted. Twelve patients with metastatic bone or soft tissue sarcoma that had failed first line chemotherapy treatment were enrolled for this study. Human tissue taken at surgical biopsy under general anaesthetic was divided between two arms of the trial. Subsections of the tumour were used for WES and the remainder was implanted subcutaneously in immunodeficient mice (PDX). Results of WES were analysed using a bioinformatics pipeline to identify mutations conferring susceptibility to kinase inhibitors and common chemotherapeutic agents. PDX models exhibiting successful growth underwent WES of the tumour and subsequent chemosensitivity testing.

Results

WES was successful in all 12 patients, with successful establishment PDX tumours models in seven patients. WES identified potential actionable therapeutics in all patients. Significant variation in predicted therapeutics was demonstrated between three PDX samples and their matched tumour samples.

Conclusion

Analysis of WES of fresh tumour specimens via a bioinformatics pipeline may identify potential actionable chemotherapy agents. Further research into this field may lead to the development of personalized cancer therapy for sarcoma.

Electronic supplementary material

The online version of this article (10.1186/s13569-018-0090-1) contains supplementary material, which is available to authorized users.

Effective molecular targeting of CDK4/6 and IGF-1R in a rare FUS-ERG fusion CDKN2A-deletion doxorubicin-resistant Ewing's sarcoma patient-derived orthotopic xenograft (PDOX) nude-mouse model

Ewing's sarcoma is a rare and aggressive malignancy. In the present study, tumor from a patient with a Ewing's sarcoma with cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) loss and FUS-ERG fusion was implanted in the right chest wall of nude mice to establish a patient-derived orthotopic xenograft (PDOX) model. The aim of the present study was to determine efficacy of cyclin-dependent kinase 4/6 (CDK4/6) and insulin-like growth factor-1 receptor (IGF-1R) inhibitors on the Ewing's sarcoma PDOX. The PDOX models were randomized into the following groups when tumor volume reached 50 mm³: G1, untreated control; G2, doxorubicin (DOX) (intraperitoneal (i.p.) injection, weekly, for 2 weeks); G3, CDK4/6 inhibitor (palbociclib, PD0332991, per oral (p.o.), daily, for 14 days); G4, IGF-1R inhibitor (linsitinib, OSI-906, p.o., daily, for 14 days). Tumor growth was significantly suppressed both in G3 (palbociclib) and in G4 (linsitinib) compared to G1 (untreated control) at all measured time points. In contrast, DOX did not inhibit tumor growth at any time point, which is consistent with the failure of DOX to control tumor growth in the patient. The results of the present study demonstrate the power of the PDOX model to identify effective targeted molecular therapy of a recalcitrant DOX-resistant Ewing's sarcoma with specific genetic alterations. The results of this study suggest the potential of PDOX models for individually-tailored, effective targeted therapy for recalcitrant cancer.

Biology and Management of Undifferentiated Pleomorphic Sarcoma, Myxofibrosarcoma, and Malignant Peripheral Nerve Sheath Tumors: State of the Art and Perspectives

Undifferentiated pleomorphic sarcomas, myxofibrosarcomas, and malignant peripheral nerve sheath tumors are characterized by complex genomic characteristics and aggressive clinical behavior. Recent advances in the understanding of the pathogenesis of these tumors may allow for the development of more-effective innovative therapeutic strategies, including immunotherapies. This review describes the current knowledge of the epidemiology, clinical presentation, treatment, and pathogenesis of these tumors and highlights ongoing and future research.

Morphometric and cytomorphologic characterization of EGFR-mutated cancer cells-comparison between cultured lung cancer cell lines and lung adenocarcinoma clinical samples

BACKGROUND

Recently molecular targeting therapies such as inhibition of enzyme activities associated with gene mutations responsible for lung carcinogenesis have been demonstrating promising outcomes, increasing the importance of gene analysis using clinical samples. Cytomorphologic findings with predictive value toward specific gene mutation such as EGFR mutation could be a useful tool to select appropriate gene analyses using limited clinical samples.

METHODS

Morphometrical and cytomorphological evaluations were performed in 7 cultured lung cancer cell lines and 51 lung adenocarcinoma clinical samples to identify specific cytomorphologic characterization of EGFR-mutated cancer cells compared to the wild type.

RESULTS

Morphometry demonstrated that the EGFR mutated cell lines had significantly smaller nuclear area and perimeter and more circular nuclei compared to the wild type. In contrast, EGFR-mutated clinical samples had significantly greater nuclear area and perimeter compared to the wild type EGFR samples. There were no clear differences in cytomorphologic parameters assessing nuclear atypicality between EGFR mutated cells and wild type EGFR cells in either cultured cell lines or clinical samples.

CONCLUSION

Although our study suggested that EGFR mutation may have specific effects on nuclear morphology, no consistent characteristics of EGFR-mutated cells were identified in the clinical samples, probably due to various factors such as different pathologic stages and various incidences of lepidic growth. Further assessment of morphological characterization of EGFR-mutated cells in lung adenocarcinoma is warranted, increasing the number of samples and considering the effects of polyploidy, other gene mutations, pathology stage and tumor subtypes such as lepidic growth. Diagn. Cytopathol. 2016;44:717-724. © 2016 Wiley Periodicals, Inc.

Sarcoma Cell Line Screen of Oncology Drugs and Investigational Agents Identifies Patterns Associated with Gene and microRNA Expression

The diversity in sarcoma phenotype and genotype make treatment of this family of diseases exceptionally challenging. Sixty-three human adult and pediatric sarcoma lines were screened with 100 FDA-approved oncology agents and 345 investigational agents. The investigational agents' library enabled comparison of several compounds targeting the same molecular entity allowing comparison of target specificity and heterogeneity of cell line response. Gene expression was derived from exon array data and microRNA expression was derived from direct digital detection assays. The compounds were screened against each cell line at nine concentrations in triplicate with an exposure time of 96 hours using Alamar blue as the endpoint. Results are presented for inhibitors of the following targets: aurora kinase, IGF-1R, MEK, BET bromodomain, and PARP1. Chemical structures, IC50 heat maps, concentration response curves, gene expression, and miR expression heat maps are presented for selected examples. In addition, two cases of exceptional responders are presented. The drug and compound response, gene expression, and microRNA expression data are publicly available at http://sarcoma.cancer.gov. These data provide a unique resource to the cancer research community.

Non-Rhabdomyosarcoma Soft Tissue Sarcomas in Children: A Surveillance, Epidemiology, and End Results Analysis Validating COG Risk Stratifications

PURPOSE

Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) are a heterogeneous group of sarcomas that encompass over 35 histologies. With an incidence of ∼500 cases per year in the United States in those <20 years of age, NRSTS are rare and therefore difficult to study in pediatric populations. We used the large Surveillance, Epidemiology, and End Results (SEER) database to validate the prognostic ability of the Children's Oncology Group (COG) risk classification system and to define patient, tumor, and treatment characteristics.

METHODS AND MATERIALS

From SEER data from 1988 to 2007, we identified patients ≤18 years of age with NRSTS. Data for age, sex, year of diagnosis, race, registry, histology, grade, primary size, primary site, stage, radiation therapy, and survival outcomes were analyzed. Patients with nonmetastatic grossly resected low-grade tumors of any size or high-grade tumors ≤5 cm were considered low risk. Cases of nonmetastatic tumors that were high grade, >5 cm, or unresectable were considered intermediate risk. Patients with nodal or distant metastases were considered high risk.

RESULTS

A total of 941 patients met the review criteria. On univariate analysis, black race, malignant peripheral nerve sheath (MPNST) histology, tumors >5 cm, nonextremity primary, lymph node involvement, radiation therapy, and higher risk group were associated with significantly worse overall survival (OS) and cancer-specific survival (CSS). On multivariate analysis, MPNST histology, chemotherapy-resistant histology, and higher risk group were significantly poor prognostic factors for OS and CSS. Compared to low-risk patients, intermediate patients showed poorer OS (hazard ratio [HR]: 6.08, 95% confidence interval [CI]: 3.53-10.47, P<.001) and CSS (HR: 6.27; 95% CI: 3.44-11.43, P<.001), and high-risk patients had the worst OS (HR: 13.35, 95% CI: 8.18-21.76, P<.001) and CSS (HR: 14.65, 95% CI: 8.49-25.28, P<.001).

CONCLUSIONS

The current COG risk group stratification for children with NRSTS has been validated with a large number of children in the SEER database.

Grading of soft tissue sarcomas: from histological to molecular assessment

Several histological grading systems for soft tissue sarcomas have been described since the early 1980s. Their main objective is to select patients for adjuvant chemotherapy. Two histological grading systems are used in daily practice, the National Cancer Institute (NCI) and the French Federation of Cancer Centers Sarcoma Group (FNCLCC) systems. They have been devised by combining histological parameters: number of mitoses per high-power field, the presence of necrosis, cellular and nuclear morphology and the degree of cellularity for the NCI grading; and tumour differentiation, mitotic index and extent of necrosis for the French system. Histological grading is far more appropriate to assess the risk of metastasis. However, several limitations prevent its use: grade cannot be applied to all histological types, its reproducibility is not perfect, a three-grade system generates an intermediate grade with undetermined prognosis, and finally the core needle biopsy, now widely used for the diagnosis of soft tissue sarcoma, is not the best sample to assess the grade. The development of molecular grading in addition to histological grading probably represents the next step. Molecular signatures based on quantitative evaluation of chromosomal complexity such as CINSARC (complexity index in sarcomas) appear as a strong independent predictive factor for metastasis in several types of sarcoma, and even in several other types of cancer. When they can be instituted in daily practice on formalin fixed, paraffin embedded material, molecular signatures will not only provide information on risk of metastasis, but also better understanding of cancer development, response or resistance to evaluated drugs, and potential targets for future treatments.

Using a rhabdomyosarcoma patient-derived xenograft to examine precision medicine approaches and model acquired resistance

BACKGROUND

Precision (Personalized) medicine has the potential to revolutionize patient health care especially for many cancers where the fundamental disease etiology remains either elusive or has no available therapy. Here we outline a study in alveolar rhabdomyosarcoma, in which we use gene expression profiling and a series of drug prediction algorithms combined with a matched patient-derived xenograft (PDX) model to test bioinformatically predicted therapies.

PROCEDURE

A PDX model was developed from a patient biopsy and a number of drugs identified using gene expression analysis in combination with drug prediction algorithms. Drugs chosen from each of the predictive methodologies, along with the patient's standard-of-care therapy (ICE-T), were tested in vivo in the PDX tumor. A second study was initiated using the tumors that re-grew following the ICE-T treatment. Further expression analysis identified additional therapies with potential anti-tumor efficacy.

RESULTS

A number of the predicted therapies were found to be active against the tumors in particular BGJ398 (FGFR2) and ICE-T. Re-transplanted ICE-T treated tumorgrafts demonstrated a decreased response to ICE-T recapitulating the patient's refractory disease. Gene expression profiling of the ICE-T treated tumorgrafts identified cytarabine (SLC29A1) as a potential therapy, which was shown, along with BGJ398, to be highly active in vivo.

CONCLUSIONS

This study illustrates that PDX models are suitable surrogates for testing potential therapeutic strategies based on gene expression analysis, modeling clinical drug resistance and hold the potential to assist in guiding prospective patient care.

Gene expression profiling in leiomyosarcomas and undifferentiated pleomorphic sarcomas: SRC as a new diagnostic marker

Background

Undifferentiated Pleomorphic Sarcoma (UPS) and high-grade Leiomyosarcoma (LMS) are soft tissue tumors with an aggressive clinical behavior, frequently developing local recurrence and distant metastases. Despite several gene expression studies involving soft tissue sarcomas, the potential to identify molecular markers has been limited, mostly due to small sample size, in-group heterogeneity and absence of detailed clinical data.

Materials and Methods

Gene expression profiling was performed for 22 LMS and 22 UPS obtained from untreated patients. To assess the relevance of the gene signature, a meta-analysis was performed using five published studies. Four genes (BAD, MYOCD, SRF and SRC) selected from the gene signature, meta-analysis and functional in silico analysis were further validated by quantitative PCR. In addition, protein-protein interaction analysis was applied to validate the data. SRC protein immunolabeling was assessed in 38 UPS and 52 LMS.

Results

We identified 587 differentially expressed genes between LMS and UPS, of which 193 corroborated with other studies. Cluster analysis of the data failed to discriminate LMS from UPS, although it did reveal a distinct molecular profile for retroperitoneal LMS, which was characterized by the over-expression of smooth muscle-specific genes. Significantly higher levels of expression for BAD, SRC, SRF, and MYOCD were confirmed in LMS when compared with UPS. SRC was the most value discriminator to distinguish both sarcomas and presented the highest number of interaction in the in silico protein-protein analysis. SRC protein labeling showed high specificity and a positive predictive value therefore making it a candidate for use as a diagnostic marker in LMS.

Conclusions

Retroperitoneal LMS presented a unique gene signature. SRC is a putative diagnostic marker to differentiate LMS from UPS.

Patient-derived xenografts for individualized care in advanced sarcoma

BACKGROUND

Patients with advanced, metastatic sarcoma have a poor prognosis, and the overall benefit from the few standard-of-care therapeutics available is small. The rarity of this tumor, combined with the wide range of subtypes, leads to difficulties in conducting clinical trials. The authors previously reported the outcome of patients with a variety of common solid tumors who received treatment with drug regimens that were first tested in patient-derived xenografts using a proprietary method ("TumorGrafts").

METHODS

Tumors resected from 29 patients with sarcoma were implanted into immunodeficient mice to identify drug targets and drugs for clinical use. The results of drug sensitivity testing in the TumorGrafts were used to personalize cancer treatment.

RESULTS

Of 29 implanted tumors, 22 (76%) successfully engrafted, permitting the identification of treatment regimens for these patients. Although 6 patients died before the completion of TumorGraft testing, a correlation between TumorGraft results and clinical outcome was observed in 13 of 16 (81%) of the remaining individuals. No patients progressed during the TumorGraft-predicted therapy.

CONCLUSIONS

The current data support the use of the personalized TumorGraft model as an investigational platform for therapeutic decision-making that can guide treatment for rare tumors such as sarcomas. A randomized phase 3 trial versus physician's choice is warranted.

Molecular pathological analysis of sarcomas using paraffin-embedded tissue: current limitations and future possibilities

Sarcomas of soft tissue and bone are rare neoplasms that can be separated into a large number of different diagnostic entities. Over the years, a number of diagnostic markers have been developed that aid pathologists in reaching the appropriate diagnoses. Many of these markers are sarcoma-specific proteins that can be detected by immunohistochemistry in formalin-fixed, paraffin-embedded (FFPE) sections. In addition, a wide range of molecular studies have been developed that can detect gene mutations, gene amplifications or chromosomal translocations in FFPE material. Until recently, most sequencing-based approaches relied on the availability of fresh frozen tissue. However, with the advent of next-generation sequencing technologies, FFPE material is increasingly being used as a tool to identify novel immunohistochemistry markers, gene mutations, and chromosomal translocations, and to develop diagnostic tests.

The influence of primary site on outcomes in leiomyosarcoma: a review of clinicopathologic differences between uterine and extrauterine disease

BACKGROUND

Leiomyosarcomas (LMS) comprise 25% of soft tissue sarcomas. Recent reports suggest differences in treatment outcomes between uterine (uLMS) and extrauterine (eLMS) disease that may reflect distinct disease biologies. We sought to identify prognostic factors in LMS and clinicopathologic differences between uLMS and eLMS.

METHODS

This is a single-center retrospective study evaluating 97 eligible patients treated for LMS between 2002 and 2010.

RESULTS

Median follow-up was 21.2 months. uLMS affected 53% of patients, and was less common beyond age 60 years compared with eLMS (10% vs. 37%, P = 0.002). Seventy-two percent of patients presented with nonmetastatic disease. Of these, 94% underwent curative surgery, among whom more uLMS patients achieved negative surgical margins (90% vs. 45%, P = 0.003). There were no significant differences in adjuvant therapy use and relapse patterns between uLMS and eLMS. Half of metastatic patients received palliative chemotherapy, among whom 76% received anthracycline-based chemotherapy in first line to which response rate was 31%. Median overall survival was 45.2 months, 49.8 months in uLMS, and 40.5 months in eLMS (P = 0.294). Among patients without metastases, median survival was 60.8 months (77.3 vs. 48.1 mo in uLMS and eLMS, respectively, P = 0.194). In metastatic disease, median survival was 20.7 months (22.0 vs. 17.5 mo in uLMS and eLMS, respectively, P = 0.936). Advanced disease stage, bone metastases and lack of metastasectomy prognosticated for inferior survival.

CONCLUSIONS

While demonstrating interesting clinicopathologic differences, the evidence for uLMS and eLMS being biologically distinct remains inconclusive. Disease stage is prognostically most important in LMS.

Desktop transcriptome sequencing from archival tissue to identify clinically relevant translocations

Somatic mutations, often translocations or single nucleotide variations, are pathognomonic for certain types of cancers and are increasingly of clinical importance for diagnosis and prediction of response to therapy. Conventional clinical assays only evaluate 1 mutation at a time, and targeted tests are often constrained to identify only the most common mutations. Genome-wide or transcriptome-wide high-throughput sequencing (HTS) of clinical samples offers an opportunity to evaluate for all clinically significant mutations with a single test. Recently a "desktop version" of HTS has become available, but most of the experience to date is based on data obtained from high-quality DNA from frozen specimens. In this study, we demonstrate, as a proof of principle, that translocations in sarcomas can be diagnosed from formalin-fixed paraffin-embedded (FFPE) tissue with desktop HTS. Using the first generation MiSeq platform, full transcriptome sequencing was performed on FFPE material from archival blocks of 3 synovial sarcomas, 3 myxoid liposarcomas, 2 Ewing sarcomas, and 1 clear cell sarcoma. Mapping the reads to the "sarcomatome" (all known 83 genes involved in translocations and mutations in sarcoma) and using a novel algorithm for ranking fusion candidates, the pathognomonic fusions and the exact breakpoints were identified in all cases of synovial sarcoma, myxoid liposarcoma, and clear cell sarcoma. The Ewing sarcoma fusion gene was detectable in FFPE material only with a sequencing platform that generates greater sequencing depth. The results show that a single transcriptome HTS assay, from FFPE, has the potential to replace conventional molecular diagnostic techniques for the evaluation of clinically relevant mutations in cancer.

The in ovo CAM-assay as a xenograft model for sarcoma

Sarcoma is a very rare disease that is heterogeneous in nature, all hampering the development of new therapies. Sarcoma patients are ideal candidates for personalized medicine after stratification, explaining the current interest in developing a reproducible and low-cost xenotransplant model for this disease. The chick chorioallantoic membrane is a natural immunodeficient host capable of sustaining grafted tissues and cells without species-specific restrictions. In addition, it is easily accessed, manipulated and imaged using optical and fluorescence stereomicroscopy. Histology further allows detailed analysis of heterotypic cellular interactions. This protocol describes in detail the in ovo grafting of the chorioallantoic membrane with fresh sarcoma-derived tumor tissues, their single cell suspensions, and permanent and transient fluorescently labeled established sarcoma cell lines (Saos-2 and SW1353). The chick survival rates are up to 75%. The model is used to study graft- (viability, Ki67 proliferation index, necrosis, infiltration) and host (fibroblast infiltration, vascular ingrowth) behavior. For localized grafting of single cell suspensions, ECM gel provides significant advantages over inert containment materials. The Ki67 proliferation index is related to the distance of the cells from the surface of the CAM and the duration of application on the CAM, the latter determining a time frame for the addition of therapeutic products.

Gene expression profiling of solitary fibrous tumors

Background

Solitary fibrous tumors (SFTs) are rare spindle-cell tumors. Their cell-of-origin and molecular basis are poorly known. They raise several clinical problems. Differential diagnosis may be difficult, prognosis is poorly apprehended by histoclinical features, and no effective therapy exists for advanced stages.

Methods

We profiled 16 SFT samples using whole-genome DNA microarrays and analyzed their expression profiles with publicly available profiles of 36 additional SFTs and 212 soft tissue sarcomas (STSs). Immunohistochemistry was applied to validate the expression of some discriminating genes.

Results

SFTs displayed whole-genome expression profiles more homogeneous and different from STSs, but closer to genetically-simple than genetically-complex STSs. The SFTs/STSs comparison identified a high percentage (∼30%) of genes as differentially expressed, most of them without any DNA copy number alteration. One of the genes most overexpressed in SFTs encoded the ALDH1 stem cell marker. Several upregulated genes and associated ontologies were also related to progenitor/stem cells. SFTs also overexpressed genes encoding therapeutic targets such as kinases (EGFR, ERBB2, FGFR1, JAK2), histone deacetylases, or retinoic acid receptors. Their overexpression was found in all SFTs, regardless the anatomical location. Finally, we identified a 31-gene signature associated with the mitotic count, containing many genes related to cell cycle/mitosis, including AURKA.

Conclusion

We established a robust repertoire of genes differentially expressed in SFTs. Certain overexpressed genes could provide new diagnostic (ALDH1A1), prognostic (AURKA) and/or therapeutic targets.

A call to ARMS: targeting the PAX3-FOXO1 gene in alveolar rhabdomyosarcoma

INTRODUCTION

Expression of fusion oncoproteins generated by recurrent chromosomal translocations represents a major tumorigenic mechanism characteristic of multiple cancers, including one-third of all sarcomas. Oncogenic fusion genes provide novel targets for therapeutic intervention. The PAX3-FOXO1 oncoprotein in alveolar rhabdomyosarcoma (ARMS) is presented as a paradigm to examine therapeutic strategies for targeting sarcoma-associated fusion genes.

AREAS COVERED

This review discusses the role of PAX3-FOXO1 in ARMS tumors. Besides evaluating various approaches to molecularly target PAX3-FOXO1 itself, this review highlights therapeutically attractive downstream genes activated by PAX3-FOXO1.

EXPERT OPINION

Oncogenic fusion proteins represent desirable therapeutic targets because their expression is specific to tumor cells, but these fusions generally characterize rare malignancies. Full development and testing of potential drugs targeted to these fusions are complicated by the small numbers of patients in these disease categories. Although efforts to develop targeted therapies against fusion proteins should continue, molecular targets that are applicable to a broader tumor landscape should be pursued. A shift of the traditional paradigm to view therapeutic intervention as target-specific rather than tumor-specific will help to circumvent the challenges posed by rare tumors and maximize the possibility of developing successful new treatments for patients with these rare translocation-associated sarcomas.

Histologic and genetic advances in refining the diagnosis of "undifferentiated pleomorphic sarcoma"

Undifferentiated pleomorphic sarcoma (UPS) is an inclusive term used for sarcomas that defy formal sub-classification. The frequency with which this diagnosis is assigned has decreased in the last twenty years. This is because when implemented, careful histologic assessment, immunohistochemistry, and ultra-structural evaluation can often determine lineage of differentiation. Further attrition in the diagnostic frequency of UPS may arise by using array-comparative genomic hybridization. Gene expression arrays are also of potential use as they permit hierarchical gene clustering. Appraisal of the literature is difficult due to a historical perspective in which specific molecular diagnostic methods were previously unavailable. The American Joint Committee on Cancer (AJCC) classification has changed with different inclusion criteria. Taxonomy challenges also exist with the older term “malignant fibrous histiocytoma” being replaced by “UPS”. In 2010 an analysis of multiple sarcoma expression databases using a 170-gene predictor, re-classified most MFH and “not-otherwise-specified” (NOS) tumors as liposarcomas, leiomyosarcomas or fibrosarcomas. Interestingly, some of the classifier genes are potential molecular therapeutic targets including Insulin-like growth factor 1 (IGF-1), Peroxisome proliferator-activated receptor γ (PPARγ), Nerve growth factor β (NGF β) and Fibroblast growth factor receptor (FGFR).

Shared cell surface marker expression in mesenchymal stem cells and adult sarcomas

Advanced adult soft-tissue sarcomas (STSs) are rare tumors with a dismal prognosis and limited systemic treatment options. STSs may originate from mesenchymal stem cells (MSCs); the latter have mainly been isolated from adult bone marrow as plastic-adherent cells with differentiation capacity into mesenchymal tissues. Recently, a panel of antibodies has been established that allows for the prospective isolation of primary MSCs with high selectivity. Similar to cancer stem cells in other malignancies, sarcoma stem cells may bear immunophenotypic similarity with the corresponding precursor, that is, MSCs. We therefore set out to establish the expression pattern of MSC markers in sarcoma cell lines and primary tumor samples by flow cytometry. In addition, fibroblasts from different sources were examined. The results document a significant amount of MSC markers shared by sarcoma cells. The expression pattern includes uniformly expressed markers, as well as MSC markers that only stained subpopulations of sarcoma cells. Expression of W5C5, W8B2 (tissue nonspecific alkaline phosphatase [TNAP]), CD344 (frizzled-4), and CD271 marked subpopulations displaying increased proliferation potential. Moreover, CD271+ cells displayed in vitro doxorubicin resistance and an increased capacity to form spheres under serum-free conditions. Interestingly, another set of antigens, including the bona fide progenitor cell markers CD117 and CD133, were not expressed. Comparative expression patterns of novel MSC markers in sarcoma cells, as well as fibroblasts and MSCs, are presented. Our data suggest a hierarchical cytoarchitecture of the most common adult type sarcomas and introduce W5C5, TNAP, CD344, and CD271 as potential sarcoma progenitor cell markers.

Multimodality therapy for metastatic sarcomas confined to the lung

Metastectomy or resection of sarcomas which have metastasized to the lung from other sites has a long and established history. At present, there are more than forty different drugs with activity in soft tissue sarcomas. A number of sarcomas demonstrate differential sensitivities to chemotherapy and targeted agents. Intimate knowledge of the biological behavior of each distinct type of sarcoma should predicate what treatment or protocol is most suitable. Certain patients might benefit from either neoadjuvant or adjuvant therapy following the resection of metastatic lesions. Much remains to be learned about the differential sensitivities of various sarcomas to different treatment regimens.

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.

Incidence of sarcoma histotypes and molecular subtypes in a prospective epidemiological study with central pathology review and molecular testing

Background

The exact overall incidence of sarcoma and sarcoma subtypes is not known. The objective of the present population-based study was to determine this incidence in a European region (Rhone-Alpes) of six million inhabitants, based on a central pathological review of the cases.

Methodology/Principal Findings

From March 2005 to February 2007, pathology reports and tumor blocks were prospectively collected from the 158 pathologists of the Rhone-Alpes region. All diagnosed or suspected cases of sarcoma were collected, reviewed centrally, examined for molecular alterations and classified according to the 2002 World Health Organization classification. Of the 1287 patients screened during the study period, 748 met the criteria for inclusion in the study. The overall crude and world age-standardized incidence rates were respectively 6.2 and 4.8 per 100,000/year. Incidence rates for soft tissue, visceral and bone sarcomas were respectively 3.6, 2.0 and 0.6 per 100,000. The most frequent histological subtypes were gastrointestinal stromal tumor (18%; 1.1/100,000), unclassified sarcoma (16%; 1/100,000), liposarcoma (15%; 0.9/100,000) and leiomyosarcoma (11%; 0.7/100,000).

Conclusions/Significance

The observed incidence of sarcomas was higher than expected. This study is the first detailed investigation of the crude incidence of histological and molecular subtypes of sarcomas.

Expression profiling in soft tissue sarcomas with emphasis on synovial sarcoma, gastrointestinal stromal tumor, and leiomyosarcoma

Sarcomas are defined as malignant neoplasms derived from mesenchymal tissues. A variety of different molecular approaches, including gene expression profiling, have identified candidate biomarkers and insights into sarcoma biology that will aid in the diagnosis and treatment of these tumors. Many gene expression profiling findings have been translated into immunohistochemical tests for diagnostic, prognostic, or predictive purposes. This review details gene expression studies done in 3 sarcomas, synovial sarcoma, gastrointestinal stromal tumor, and leiomyosarcoma.