Integrated genetic and epigenetic analysis of myxofibrosarcoma

Establishment and characterization of two novel patient-derived cell lines from myxofibrosarcoma: NCC-MFS7-C1 and NCC-MFS8-C1

Myxofibrosarcoma (MFS), an aggressive soft tissue sarcoma, presents a significant challenge because of its high recurrence rate, distal metastasis, and complex genetic background. Although surgical resection is the standard treatment for MFS, the outcomes are unsatisfactory and effective non-surgical treatment strategies, including drug therapy, are urgently warranted. MFS is a rare tumor that requires comprehensive preclinical research to develop promising drug therapies; however, only two MFS cell lines are publicly available worldwide. The present study reports two novel patient-derived MFS cell lines, NCC-MFS7-C1 and NCC-MFS8-C1. These cell lines have been extensively characterized for their genetic profile, proliferation, spheroid-forming capacity, and invasive behavior, confirming that they retain MFS hallmarks. Furthermore, we conducted comprehensive drug screening against these cell lines and six others previously established in our laboratory to identify potential therapeutic candidates for MFS. Among the screened agents, actinomycin D, bortezomib, and romidepsin demonstrated considerable antiproliferative effects that were superior to those of doxorubicin, a standard drug, highlighting their potential as novel drugs. In conclusion, NCC-MFS7-C1 and NCC-MFS8-C1 are valuable research resources that contribute to the understanding of the pathogenesis and development of novel therapies for MFS.

Mesenchymal Tumors of the Skin: A Review

Mesenchymal tumors of the skin are rare and clinically heterogeneous, and can represent diagnostic challenge for pathologists. Most of these lesions have overlapping clinical and histological features, thus the understanding of architectural patterns, cytoplasmic and stromal features can facilitate proper diagnosis. Anatomic site may be an important factor in the differential diagnosis, as are patient's age and sex. Ancillary tests are often required and can be useful to rule out other entities. Molecular diagnostics is playing an increasingly important role in the diagnosis of soft tissue neoplasms. Here, we review clinical, histological, and molecular features of some of the most common of these uncommon entities including benign and malignant lesions.

Genetic Screen in a Preclinical Model of Sarcoma Development Defines Drivers and Therapeutic Vulnerabilities

PURPOSE

High-grade complex karyotype sarcomas are a heterogeneous group of tumors with a uniformly poor prognosis. Within complex karyotype sarcomas, there are innumerable genetic changes but identifying those that are clinically relevant has been challenging.

EXPERIMENTAL DESIGN

To address this, we utilized a pooled genetic screening approach, informed by The Cancer Genome Atlas (TCGA) data, to identify key drivers and modifiers of sarcoma development that were validated in vivo.

RESULTS

YAP1 and wild-type KRAS were validated as drivers and transformed human mesenchymal stem cells into two distinct sarcoma subtypes, undifferentiated pleomorphic sarcoma and myxofibrosarcoma, respectively. A subset of tumors driven by CDK4 and PIK3CA reflected leiomyosarcoma and osteosarcoma demonstrating the plasticity of this approach and the potential to investigate sarcoma subtype heterogeneity. All generated tumors histologically reflected human sarcomas and had increased aneuploidy as compared to simple karyotype sarcomas. Comparing differential gene expression of TCGA samples to model data identified increased oxidative phosphorylation signaling in YAP1 tumors. Treatment of a panel of soft tissue sarcomas with a combination of YAP1 and oxidative phosphorylation inhibitors led to significantly decreased viability.

CONCLUSIONS

Transcriptional co-analysis of TCGA patient samples to YAP1 and KRAS model tumors supports that these sarcoma subtypes lie along a spectrum of disease and adds guidance for further transcriptome-based refinement of sarcoma subtyping. This approach can be used to begin to understand pathways and mechanisms driving human sarcoma development, the relationship between sarcoma subtypes, and to identify and validate new therapeutic vulnerabilities for this aggressive and heterogeneous disease.

Stimulator of Interferon Genes-Activated Biomimetic Dendritic Cell Nanovaccine as a Chemotherapeutic Booster to Enhance Systemic Fibrosarcoma Treatment

Fibrosarcoma, a malignant mesenchymal tumor, is characterized by aggressive invasiveness and a high recurrence rate, leading to poor prognosis. Anthracycline drugs, such as doxorubicin (DOX), represent the frontline chemotherapy for fibrosarcoma, but often exhibit suboptimal efficacy. Recently, exploiting the stimulator of interferon genes (STING)-mediated innate immunity has emerged as a hopeful strategy for cancer treatment. Integrating chemotherapy with immunomodulators in chemo-immunotherapy has shown potential for enhancing treatment outcomes. Herein, we introduce an advanced dendritic cell (DC) nanovaccine, cGAMP@PLGA@CRTM (GP@CRTM), combined with low-dose DOX to enhance fibrosarcoma chemo-immunotherapy. The nanovaccine consists of poly(lactic-co-glycolic acid) (PLGA) nanoparticles encapsulating the STING agonist 2,3-cGAMP (cGAMP@PLGA, GP) as its core, and a calreticulin (CRT) high-expressing fibrosarcoma cell membrane (CRTM) as the shell. Exposing CRT on the vaccine surface aids in recruiting DCs and stimulating uptake, facilitating efficient simultaneous delivery of STING agonists and tumor antigens to DCs. This dual delivery method effectively activates the STING pathway in DCs, triggering sustained immune stimulation. Simultaneously, low-dose DOX reduces chemotherapy-related side effects, directly kills a subset of tumor cells, and increases tumor immunogenicity, thus further amplifying immune therapeutic performance. Hence, these findings demonstrate the potential of DC nanovaccine GP@CRTM as a booster for chemotherapy. Synergistically combining low-dose DOX with the DC nanovaccine emerges as a powerful chemo-immunotherapy strategy, optimizing systemic fibrosarcoma therapy.

p53 as a Potential Actionable Target in Myxofibrosarcoma: A Molecular and Pathologic Review of a Single-Institute Series

Myxofibrosarcoma (MFS) is a common adult soft tissue sarcoma characterized by high-local recurrence rate, poorly understood molecular pathogenesis, lack of specific prognostic markers, and effective targeted therapies. To gain further insights into the disease, we analyzed a well-defined group of 133 primary MFS cases. Immunohistochemical (IHC) staining for p53, MET, RET, and RB was performed. Twenty-five cases were analyzed by targeted resequencing of known cancer driver hotspot mutations, whereas 66 and 64 MFSs were examined for the presence of genetic variants in TP53 and MET gene, respectively. All clinical, histologic, immunostaining, and genetic variables were analyzed for their impact on 5-years overall survival (OS) and 5-years event-free survival (EFS). In our series, no grade I tumors relapsed and high grade are related to a positive MET immunostaining (P = .034). Both local recurrence (P = .038) and distal metastases (P = .016) correlated to the presence of "single nucleotide variant (SNV) plus copy number variation (CNV)" in TP53. Multivariate analysis revealed that age (>60 years), metastasis at presentation, and positive IHC-p53 signal are risk factors for a poor OS (P = .003, P = .000, and P = .002), whereas age (>60 years), synchronous metastasis, and tumor size (>10 cm) predict an unfavorable 5-years EFS (P = .011, P = .000, and P = .023). Considering the smaller series (n = 66) that underwent molecular screening, the presence of "SNV+CNV" in TP53 represents a risk factor for a worse 5-years EFS (hazard ratio, 2.5; P = .017). The present series confirms that TP53 is frequently altered in MFS (86.4% of cases), appearing to play an important role in MFS tumorigenesis and being a potentially drugable target. A positive p53 immunostainings is related to a poor diagnosis, and it is the presence of a single nucleotide genetic alterations in TP53 that is essential in conferring MFS an aggressive phenotype, thus supporting the use of molecular profiling in MFS to better define the role of p53 as a prognostic factor.

Myxoid liposarcoma diagnosed on fine needle aspiration cytology: There is more to it than meets the eye

ABSTRACT

Liposarcoma is a rare mesenchymal neoplasm commonly involving deep soft tissues and the retroperitoneum. Among the various types of liposarcoma, myxoid liposarcoma is the most frequently encountered in adolescents and young adults, with a predilection for lower extremities. Fine needle aspiration allows easy assessment and rapid on-site evaluation for distinguishing benign from malignant lipomatous lesions. Here, we present a case of myxoid liposarcoma in the calf region of a 19-year-old boy, diagnosed via fine needle aspiration cytology, and subsequently confirmed by histopathological examination after surgical resection. The intention behind this case report is to highlight the cytological features of myxoid liposarcoma and to improve understanding of this tumor entity, aiming to prevent misdiagnosis by inexperienced pathologists when evaluating cytology specimens.

Disaggregation-Activated pan-COX Imaging Agents for Human Soft tissue Sarcoma

Cancer stem cells are pivotal players in tumors initiation, growth, and metastasis. While several markers have been identified, there remain challenges particularly in heterogeneous malignancies like adult soft tissue sarcomas, where conventional markers are inherently overexpressed. Here, we designed BODIPY scaffold fluorescence probes (BD-IMC-1, BD-IMC-2) that activate via disaggregation targeting for cyclooxygenase (COX), a potential marker for CSCs in sarcoma in clinical pathology. Based on their structures, BD-IMC-1 showcased higher susceptibility to disaggregation compared to BD-IMC-2, consistent with their selective interaction with COX. Notably, the BD-IMC-1 revealed positive cooperativity binding to COX-2 at sub-micromolar ranges. Both probes showed significant fluorescence turn-on upon LPS or PMA triggered COX-2 upregulation in live RAW264.7, HeLa, and human sarcoma cell line (Saos-LM2) up to 2-fold increase with negligible toxicity. More importantly, the BD-IMC-1 demonstrated their practical imaging for COX-2 positive cells in paraffin-fixed human sarcoma tissue. Considering the fixed tissues are most practiced pathological sample, our finding suggests a potential of disaggregation activated chemosensor for clinical applications.

Pan-cancer Genomic Analysis of AXL Mutations Reveals a Novel, Recurrent, Functionally Activating AXL W451C Alteration Specific to Myxofibrosarcoma

Myxofibrosarcoma (MFS) is a common soft tissue sarcoma of the elderly that typically shows low tumor mutational burden, with mutations in TP53 and in genes associated with cell cycle checkpoints ( RB1 , CDKN2A ). Unfortunately, no alterations or markers specific to MFS have been identified and, as a consequence, there are no effective targeted therapies. The receptor tyrosine kinase AXL, which drives cellular proliferation, is targetable by new antibody-based therapeutics. Expression of AXL messenger RNA is elevated in a variety of sarcoma types, with the highest levels reported in MFS, but the pathogenic significance of this finding remains unknown. To assess a role for AXL abnormalities in MFS, we undertook a search for AXL genomic alterations in a comprehensive genomic profiling database of 463,546 unique tumors (including 19,879 sarcomas, of which 315 were MFS) interrogated by targeted next-generation DNA and/or RNA sequencing. Notably, the only genomic alterations recurrent in a specific sarcoma subtype were AXL W451C (n = 8) and AXL W450C (n = 2) mutations. The tumors involved predominantly older adults (age: 44 to 81 [median: 72] y) and histologically showed epithelioid and spindle-shaped cells in a variably myxoid stroma, with 6 cases diagnosed as MFS, 3 as undifferentiated pleomorphic sarcoma (UPS), and 1 as low-grade sarcoma. The AXL W451C mutation was not identified in any non-sarcoma malignancy. A review of publicly available data sets revealed a single AXL W451C-mutant case of UPS that clustered with MFS/UPS by methylation profiling. Functional studies revealed a novel activation mechanism: the W451C mutation causes abnormal unregulated dimerization of the AXL receptor tyrosine kinase through disulfide bond formation between pairs of mutant proteins expressing ectopic cysteine residues. This dimerization triggers AXL autophosphorylation and activation of downstream ERK signaling. We further report sarcomas of diverse histologic subtypes with AXL gene amplifications, with the highest frequency of amplification identified in MFS cases without the W451C mutation. In summary, the activating AXL W451C mutation appears highly specific to MFS, with a novel mechanism to drive unregulated signaling. Moreover, AXL gene amplifications and messenger RNA overexpression are far more frequent in MFS than in other sarcoma subtypes. We conclude that these aberrations in AXL are distinct features of MFS and may aid diagnosis, as well as the selection of available targeted therapies.

The Role of Methylation Analysis in Distinguishing Cellular Myxoma from Low-Grade Myxofibrosarcoma

Cellular myxoma is a benign soft tissue tumor frequently associated with GNAS mutation that may morphologically resemble low-grade myxofibrosarcoma. This study aimed to identify the undescribed methylation profile of cellular myxoma and compare it to myxofibrosarcoma. We performed molecular analysis on twenty cellular myxomas and nine myxofibrosarcomas and analyzed the results using the methylation-based DKFZ sarcoma classifier. A total of 90% of the cellular myxomas had GNAS mutations (four loci had not been previously described). Copy number variations were found in all myxofibrosarcomas but in none of the cellular myxomas. In the classifier, none of the cellular myxomas reached the 0.9 threshold. Unsupervised t-SNE analysis demonstrated that cellular myxomas form their own clusters, distinct from myxofibrosarcomas. Our study shows the diagnostic potential and the limitations of molecular analysis in cases where morphology and immunohistochemistry are not sufficient to distinguish cellular myxoma from myxofibrosarcoma, particularly regarding GNAS wild-type tumors. The DKFZ sarcoma classifier only provided a valid prediction for one myxofibrosarcoma case; this limitation could be improved by training the tool with a more considerable number of cases. Additionally, the classifier should be introduced to a broader spectrum of mesenchymal neoplasms, including benign tumors like cellular myxoma, whose distinct methylation pattern we demonstrated.

MDM2 Amplification Status in a Cohort of Well-Characterized Myxofibrosarcoma: A Clinicopathologic Analysis of 22 Tumors

Myxofibrosarcomas (MFS) present as slowly enlarging superficial masses in elderly patients. Even though these tumors fail to exhibit a distinct immunophenotype, diagnosis is straightforward when they present in subcutaneous tissue. Intramuscular MFS, however, are more challenging to diagnose as the differential also includes dedifferentiated liposarcoma with myxoid features. The vast majority of dedifferentiated liposarcomas show MDM2 amplification, whereas limited data exists as to the MDM2 status of MFS. We sought to explore the rate of MDM2 amplification in cases of classic MFS. Our archives were searched for MFS; only subcutaneous well-sampled resections were included. FISH for MDM2 amplification was performed on each tumor. A cohort of myxoid dedifferentiated liposarcoma resections was studied for comparison. Twenty-two MFS arose in patients aged 44 to 85 years. All tumors contained an infiltrative population of atypical cells embedded in a myxoid stroma with curvilinear blood vessels. MDM2 amplification by FISH was identified in 3 (of 22; 14%) tumors. Available follow up on 17 patients (range 1-96 months; median 13 months) revealed 6 patients with local recurrence and 1 with distant metastasis. Of 3 patients with MDM2- amplified MFS, 1 experienced recurrence and died of unrelated causes, while the second was alive without disease 12 months after diagnosis. Even though the rate of MDM2 amplification by FISH in MFS appears to be low, a subset of cases may show this genetic alteration, which pathologists should be aware of to avoid misclassification as myxoid dedifferentiated liposarcomas. Further studies are necessary to determine if amplification status adds prognostic value.

Functional Classification of Fusion Proteins in Sarcoma

Sarcomas comprise a heterogeneous group of malignant tumors of mesenchymal origin. More than 80 entities are associated with different mesenchymal lineages. Sarcomas with fibroblastic, muscle, bone, vascular, adipocytic, and other characteristics are distinguished. Nearly half of all entities contain specific chromosomal translocations that give rise to fusion proteins. These are mostly pathognomonic, and their detection by various molecular techniques supports histopathologic classification. Moreover, the fusion proteins act as oncogenic drivers, and their blockade represents a promising therapeutic approach. This review summarizes the current knowledge on fusion proteins in sarcoma. We categorize the different fusion proteins into functional classes, including kinases, epigenetic regulators, and transcription factors, and describe their mechanisms of action. Interestingly, while fusion proteins acting as transcription factors are found in all mesenchymal lineages, the others have a more restricted pattern. Most kinase-driven sarcomas belong to the fibroblastic/myofibroblastic lineage. Fusion proteins with an epigenetic function are mainly associated with sarcomas of unclear differentiation, suggesting that epigenetic dysregulation leads to a major change in cell identity. Comparison of mechanisms of action reveals recurrent functional modes, including antagonism of Polycomb activity by fusion proteins with epigenetic activity and recruitment of histone acetyltransferases by fusion transcription factors of the myogenic lineage. Finally, based on their biology, we describe potential approaches to block the activity of fusion proteins for therapeutic intervention. Overall, our work highlights differences as well as similarities in the biology of fusion proteins from different sarcomas and provides the basis for a functional classification.

Modeling Myxofibrosarcoma: Where Do We Stand and What Is Missing?

Myxofibrosarcoma (MFS) is a malignant soft tissue sarcoma (STS) that originates in the body's connective tissues. It is characterized by the presence of myxoid (gel-like) and fibrous components and typically affects patients after the fifth decade of life. Considering the ongoing trend of increasing lifespans across many nations, MFS is likely to become the most common musculoskeletal sarcoma in the future. Although MFS patients have a lower risk of developing distant metastases compared with other STS cases, MFS is characterized by a high frequency of local recurrence. Notably, in 40-60% of the patients where the tumor recurs, it does so multiple times. Consequently, patients may undergo multiple local surgeries, removing the risk of potential amputation. Furthermore, because the tumor relapses generally have a higher grade, they exhibit a decreased response to radio and chemotherapy and an increased tendency to form metastases. Thus, a better understanding of MFS is required, and improved therapeutic options must be developed. Historically, preclinical models for other types of tumors have been instrumental in obtaining a better understanding of tumor development and in testing new therapeutic approaches. However, few MFS models are currently available. In this review, we will describe the MFS models available and will provide insights into the advantages and constraints of each model.

Biology and Management of High-Grade Myxofibrosarcoma: State of the Art and Future Perspectives

Myxofibrosarcoma (MFS) is one of the most common adult soft tissue sarcomas, typically arising in the extremities. Histologically, MFS is classified into three grades: low, intermediate, and high. Histological grades correlate with distant metastases and tumor-associated mortality. The diagnosis of MFS is challenging due to a lack of well-characterized immunohistochemical markers. High-grade MFS displays highly complex karyotypes with multiple copy number alterations. Recent integrated genomic studies have shown the predominance of somatic copy number aberrations. However, the molecular pathogenesis of high-grade MFS remains poorly understood. The standard treatment for localized MFS is surgical resection. The systemic treatment options for advanced disease are limited. This review provides an updated overview of the clinical and imaging features, pathogenesis, histopathology, and treatment of high-grade MFS.

Heart Transplantation as a Treatment Option for Recurrent Myxofibrosarcoma: A Clinical Case

Myxofibrosarcoma is one of the most rare tumors of the heart. Surgical resection is the principal method of treatment; however, in some cases, radical removal of the tumor is not possible. Here, we present a case of heart transplant in a patient who experienced recurrent myxofibrosarcoma of the left atrium and examine the morphological features of this tumor. A 40-year-old female patient presented for treatment for heart failure of a high functional class. An examination revealed a tumor in the left atrial cavity, which was subsequently surgically removed. Morphological examination revealed an inflammatory myofibroblastic tumor. After 2 years, the patient's tumor recurred. The tumor was removed, and a morphological study again diagnosed myxofibrosarcoma of the heart. A year later, recurrence was again diagnosed. Instrumental examination determined that the tumor had incurred into the mitral valve and possibly spread to the myocardium. Tumor resection was not possible, and the need to perform a heart transplant was determined. The given case contributes to the practical conclusion that heart transplant contributes to an increase in the life expectancy for patients with inoperable cases of cardiac sarcoma.

Exceptional Response to MEK Inhibition in a Patient With RAF1-Mutant Myxofibrosarcoma: Case Report and Mechanistic Overview

Complete response to Trametinib in a heavily-pretreated sarcoma: RAF1 as a predictor of MEKi Response

Addressing Modern Diagnostic Pathology for Patient-Derived Soft Tissue Sarcosphere Models in the Era of Functional Precision Oncology

Responses to therapy often cannot be exclusively predicted by molecular markers, thus evidencing a critical need to develop tools for better patient selection based on relations between tumor phenotype and genotype. Patient-derived cell models could help to better refine patient stratification procedures and lead to improved clinical management. So far, such ex vivo cell models have been used for addressing basic research questions and in preclinical studies. As they now enter the era of functional precision oncology, it is of utmost importance that they meet quality standards to fully represent the molecular and phenotypical architecture of patients' tumors. Well-characterized ex vivo models are imperative for rare cancer types with high patient heterogeneity and unknown driver mutations. Soft tissue sarcomas account for a very rare, heterogeneous group of malignancies that are challenging from a diagnostic standpoint and difficult to treat in a metastatic setting because of chemotherapy resistance and a lack of targeted treatment options. Functional drug screening in patient-derived cancer cell models is a more recent approach for discovering novel therapeutic candidate drugs. However, because of the rarity and heterogeneity of soft tissue sarcomas, the number of well-established and characterized sarcoma cell models is extremely limited. Within our hospital-based platform we establish high-fidelity patient-derived ex vivo cancer models from solid tumors for enabling functional precision oncology and addressing research questions to overcome this problem. We here present 5 novel, well-characterized, complex-karyotype ex vivo soft tissue sarcosphere models, which are effective tools to study molecular pathogenesis and identify the novel drug sensitivities of these genetically complex diseases. We addressed the quality standards that should be generally considered for the characterization of such ex vivo models. More broadly, we suggest a scalable platform to provide high-fidelity ex vivo models to the scientific community and enable functional precision oncology.

GLUT-1 expression is helpful to distinguish myxofibrosarcoma from nodular fasciitis

Myxofibrosarcoma (MFS) is a fibroblastic/myofibroblastic neoplasm with a variably myxoid stroma. Histologically, MFS shows a wide spectrum of cellularity, pleomorphism and proliferative activity. Because of its variable morphology and lack of discriminatory markers, MFS can be difficult to distinguish from some benign soft-tissue tumors, especially nodular fasciitis (NF). Glucose transporter 1 (GLUT-1) is expressed in a variety of malignant mesenchymal tumors. In the current study, we evaluated GLUT-1 expression to determine its value in distinguishing MFS from NF. Tissue specimens from 14 MFS cases and 16 NF cases were sectioned and stained for GLUT-1 using immunohistochemistry. The percentage of GLUT-1-positive cells was scored as follows: 0 (no staining), 1+ (1-19%), 2+ (20-50%) and 3+ (>50%). Samples with a score of 1+ were defined as GLUT1-expressing samples. GLUT-1 expression was seen in all 14 MFS cases, whereas only 6 NF cases (37.5%) were positive for GLUT-1 and were scored 1+. Notably, 2-3+ GLUT-1 expression was found in 86% of MFS cases and 0% of NF cases. Our results indicate that GLUT-1 is a highly sensitive immunohistochemical marker for MFS and may be useful for the differential diagnosis of MFS and NF.

Establishment and characterization of NCC-MFS6-C1: a novel patient-derived cell line of myxofibrosarcoma

Myxofibrosarcoma (MFS) is a rare and aggressive mesenchymal malignancy characterized by complex karyotypes with heterogeneous clinical features. The standard treatment for primary MFS is curative resection; however, the utility of systemic chemotherapy and radiotherapy has not been established. Although patient-derived cancer cell lines are a key bioresource for developing novel therapies, the number of MFS cell lines available from public cell banks is limited by the rarity of the disease, and large-scale drug screening has not yet been performed. To address this issue, we aimed to establish and characterize a novel MFS cell line. We successfully established a cell line, NCC-MFS6-C1, which harbors genetic abnormalities common in MFS and exhibits aggressive phenotypes such as continuous growth, spheroid formation, and invasion in tissue culture conditions. We performed drug screening using NCC-MFS6-C1 along with five MFS cell lines established in our laboratory and clarified the response spectrum of 214 existing anticancer agents. We found that two anticancer agents, gemcitabine and romidepsin, showed considerable antiproliferative effects, and these observations were concordant with the findings of our previous report, in which these agents attenuated the proliferation of five previously reported MFS cell lines. We conclude that NCC-MFS6-C1 is a useful resource for studying MFS.

The Role of CDK Pathway Dysregulation and Its Therapeutic Potential in Soft Tissue Sarcoma

Soft tissue sarcomas (STSs) are tumors that are challenging to treat due to their pathologic and molecular heterogeneity and their tumor biology that is not yet fully understood. Recent research indicates that dysregulation of cyclin-dependent kinase (CDK) signaling pathways can be a strong driver of sarcogenesis. CDKs are enzyme forms that play a crucial role in cell-cycle control and transcription. They belong to the protein kinases group and to the serine/threonine kinases subgroup. Recently identified CDK/cyclin complexes and established CDK/cyclin complexes that regulate the cell cycle are involved in the regulation of gene expression through phosphorylation of critical components of transcription and pre-mRNA processing mechanisms. The current and continually growing body of data shows that CDKs play a decisive role in tumor development and are involved in the proliferation and growth of sarcoma cells. Since the abnormal expression or activation of large numbers of CDKs is considered to be characteristic of cancer development and progression, dysregulation of the CDK signaling pathways occurs in many subtypes of STSs. This review discusses how reversal and regulation can be achieved with new therapeutics and summarizes the current evidence from studies regarding CDK modulation for STS treatment.

Myxofibrosarcoma landscape: diagnostic pitfalls, clinical management and future perspectives

Myxofibrosarcoma (MFS) is a common entity of adult soft tissue sarcomas (STS) characterized by a predilection of the extremities and a high local recurrence rate. Originally classified as a myxoid variant of malignant fibrous histiocytoma, this musculoskeletal tumor has been recognized since 2002 as a distinct histotype showing a spectrum of malignant fibroblastic lesions with myxoid stroma, pleomorphism and curvilinear vessels. Currently, the molecular pathogenesis of MFS is still poorly understood and its genomic profile exhibits a complex karyotype with a number of aberrations including amplifications, deletions and loss of function. The diagnosis is challenging due to the unavailability of specific immunohistochemical markers and is based on the analysis of cytomorphologic features. The mainstay of treatment for localized disease is represented by surgical resection, with (neo)-adjuvant radio- and chemotherapy. In the metastatic setting, chemotherapy represents the backbone of treatments, however its role is still controversial and the outcome is very poor. Recent advent of genomic profiling, targeted therapies and larger enrollment of patients in translational and clinical studies, have improved the understanding of biological behavior and clinical outcome of such a disease. This review will provide an overview of current diagnostic pitfalls and clinical management of MFS. Finally, a look at future directions will be discussed.

Molecular and clinicopathological analysis revealed an immuno-checkpoint inhibitor as a potential therapeutic target in a subset of high-grade myxofibrosarcoma

This study aimed to identify differences in genetic alterations between low- and high-grade lesions in myxofibrosarcoma (MFS) and to examine the efficacy of immune checkpoint inhibitors in 45 patients with MFS. First, genetic differences between low- and high-grade components within the same tumor were analyzed in 11 cases using next-generation sequencing. Based on the obtained data, Sanger sequencing was performed for TP53 mutations in the remaining 34 patients. Loss of heterozygosity (LOH) analysis was performed at the TP53 and RB1 loci. Immunohistochemistry was performed for FGFR3, KIT, MET, programmed death receptor ligand 1 (PD-L1), CD8, FOXP3, and mismatch repair proteins. The microsatellite instability status was also evaluated in all cases. TP53 deleterious mutations and LOH at TP53 and RB1 loci were detected significantly more frequently in high-grade than in low-grade MFS (P = 0.0423, 0.0455, and 0.0455, respectively). LOH at the RB1 locus was significantly associated with shorter recurrence-free survival in both univariate and multivariate analyses. TP53 alterations, such as mutation and LOH, were more frequently observed in low-grade areas within high-grade MFS than in pure low-grade MFS. The positive PD-L1 expression rate was 35.6% (16/45), and all these 16 cases were high-grade. A high density of both CD8+ and FOXP3+ tumor-infiltrating lymphocytes was associated with PD-L1 positivity. LOH at the RB1 locus was identified an independent adverse prognostic factor for recurrence-free survival in patients with MFS. Immune checkpoint inhibitors may be a therapeutic option for a subset of high-grade MFS.

The landscape of genetic aberrations in myxofibrosarcoma

Myxofibrosarcoma (MFS) is a rare subtype of sarcoma, whose genetic basis is poorly understood. We analyzed 69 MFS cases using whole-genome (WGS), whole-exome (WES), and/or targeted-sequencing (TS). Newly sequenced genomic data were combined with additional deposited 116 MFS samples. WGS identified a high number of structural variations (SVs) per tumor most frequently affecting the TP53 and RB1 loci, 40% of tumors showed a BRCAness-associated mutation signature, and evidence of chromothripsis was found in all cases. Most frequently mutated /copy number altered genes affected known disease drivers such as TP53 (56.2%), CDKN2A/B (29.7%), RB1 (27.0%), ATRX (19.5%), and HDLBP (18.9%). Several previously unappreciated genetic aberrations including MUC17, FLG, and ZNF780A were identified in more than 20% of patients. Longitudinal analysis of paired diagnosis and relapse time points revealed a 1.2-fold mutation number increase accompanied with substantial changes in clonal composition over time. This study highlights the genetic complexity underlying sarcomagenesis of MFS. This article is protected by copyright. All rights reserved.

Primary cardiac undifferentiated pleomorphic sarcoma is associated with TP53 mutation during lack of MDM2 amplification, and targeted sequencing analysis reveals potentially actionable targets

Cardiac undifferentiated pleomorphic sarcoma (UPS) is a rare malignancy. Several studies have revealed frequent MDM2, CDK4, PDFGRA, and KIT amplifications and CDKN2A and CDKN2B deletions. Cases lacking the above copy number alterations may harbor alternative driver mutations; however, little is known about such occurrences. This study was conducted to gain further insights into the molecular features of cardiac UPS using targeted sequencing of 560 cancer-related genes, and fluorescence in situ hybridization and immunohistochemistry of MDM2, CDK4, CDKN2A, TP53, and RB1 in 9 cardiac UPS cases. TP53 mutation or CDKN2A deletion was found in cases lacking MDM2 amplification. Further, p53 overexpression was detected in the case with TP53 mutation, while p16 expression was completely lost in the case with CDKN2A homozygous deletion. p16 overexpression was found in cases with MDM2 and CDK4 amplification but without CDKN2A deletion. Immunohistochemistry of MDM2, CDK4, p53, and p16 is expected to be preliminarily used for gene status analysis. As cardiac UPS and intimal sarcomas are merging into a single spectrum, mutation data for 3 cardiac UPS and 9 intimal sarcomas from the literature, as well as data for 5 cardiac UPS in our study were evaluated, and known recurrently mutated cancer driver genes, including PDGFRB, TP53, ALK, PTCH1, RET, ERBB4, JAK3, GATA1, PIK3CG, and RARA, were identified. Several new potentially actionable mutations, including those in RARA, ALK, PTCH1, RET, ROS1, ABL1, and MET, were also found. These findings improve the molecular understanding of this rare malignancy and are expected to provide a basis for developing precision therapeutics for cardiac UPS and intimal sarcomas.

Clinical Utility of CDK4/6 Inhibitors in Sarcoma: Successes and Future Challenges

PURPOSE

Soft tissue and bone sarcomas are rare malignancies that exhibit significant pathologic and molecular heterogeneity. Deregulation of the CDKN2A-CCND-CDK4/6-retinoblastoma 1 (Rb) pathway is frequently observed in about 25% of unselected sarcomas and is pathognomonic for specific sarcoma subtypes. This genomic specificity has fueled the clinical evaluation of selective CDK4/6 inhibitors in sarcomas. Here, we highlight successes, opportunities, and future challenges for using CDK4/6 inhibitors to treat sarcoma.

MATERIALS AND METHODS

This review summarizes the current evidence for the use of CDK4/6 inhibitors in sarcoma while identifying molecular rationale and predictive biomarkers that provide the foundation for targeting the CDK4/6 pathway in sarcoma. A systematic review was performed of articles indexed in the PubMed database and the National Institutes of Health Clinical Trials Registry (ClinicalTrials.gov). For each sarcoma subtype, we discuss the preclinical rationale, case reports, and available clinical trials data.

RESULTS

Despite promising clinical outcomes in a subset of sarcomas, resistance to CDK4/6 inhibitors results in highly heterogeneous clinical outcomes. Current clinical data support the use of CDK4/6 inhibitors in subsets of sarcoma primarily driven by CDK4/6 deregulation. When dysregulation of the Rb pathway is a secondary driver of sarcoma, combination therapy with CDK4/6 inhibition may be an option. Developing strategies to identify responders and the mechanisms that drive resistance is important to maximize the clinical utility of these drugs in patients with sarcoma. Potential biomarkers that indicate CDK4/6 inhibitor sensitivity in sarcoma include CDK4, CCND, CCNE, RB1, E2F1, and CDKN2A.

CONCLUSION

CDK4/6 inhibitors represent a major breakthrough for targeted cancer treatment. CDK4/6 inhibitor use in sarcoma has led to limited, but significant, early clinical success. Targeted future clinical research will be key to unlocking the potential of CDK4/6 inhibition in sarcoma.

A Functional Precision Oncology Approach to Identify Treatment Strategies for Myxofibrosarcoma Patients

In this era of precision medicine, numerous workflows for the targeting of high-recurrent mutations in common tumor types have been developed, leaving patients with rare diseases with few options. Here, we implement a functional precision oncology approach utilizing comprehensive genomic profiling in combination with high-throughput drug screening, to identify tumor-specific drug sensitivities for patients with rare tumor types such as myxofibrosarcoma. From a patient with a high-grade myxofibrosarcoma, who was enrolled in the Englander Institute for Precision Medicine (EIPM) program, we established patient-derived 3D sarco-spheres and xenograft models for functional testing. In the absence of a large cohort of clinically similar cases, high-throughput drug screening was performed on the patient-derived cells, and compared with two other myxofibrosarcoma lines and a benign fibroblast line to functionally identify tumor-specific drug sensitivities. The addition of functional drug sensitivity testing to complement genomic profiling identified multiple therapeutic options that were further validated in patient derived xenograft models. Genomic analyses detected the frequently known codeletion of the tumor suppressors CDKN2A/B together with the methylthioadenosine phosphorylase (MTAP) and a TP53 E286fs*50 mutation. High-throughput drug screening demonstrated tumor-specific sensitivity to compounds targeting the cell cycle. Based on genomic analysis and high-throughput drug screening, we show that targeting the cell cycle in these tumors is a powerful approach. IMPLICATIONS: This study demonstrates the potential of functional testing to aid clinical decision making for patients with rare or molecularly complex malignancies when combined with comprehensive genomic profiling.

Development of Personalized Signature Based on the Immune Landscape to Predict the Prognosis of Osteosarcoma and the Response to Immunotherapy and Targeted Therapy

As a heterogeneous and aggressive disease, osteosarcoma (OS) faces great challenges to prognosis and individualized treatment. Hence, we explore the role of immune-related genes in predicting prognosis and responsiveness to immunotherapy and targeted therapies in patients with OS based on the immunological landscape of osteosarcoma. Based on the database of the Therapeutical Applicable Research to Generate Effective Treatments (TARGET), single-sample gene set enrichment analysis (ssGSEA) was used to obtain the enrichment scores of 29 immune characteristics. A series of bioinformatics methods were performed to construct the immune-related prognostic signature (IRPS). Gene set enrichment analysis and gene set variation analysis were used to explore the biological functions of IRPS. We also analyzed the relationship between IRPS and tumor microenvironment. Lastly, the reactivity of IRPS to immune checkpoint therapy and targeted drugs was explored. The ssGSEA algorithm was used to define two immune subtypes, namely Immunity_High and Immunity_Low. Immunity_High was associated with a good prognosis and was an independent prognostic factor of OS. The IRPS containing 7 genes was constructed by the least absolute shrinkage and selection operator Cox regression. The IRPS can divide patients into low- and high-risk patients. Compared with high-risk patients, low-risk patients had a better prognosis and were positively correlated with immune cell infiltration and immune function. Low-risk patients benefited more from immunotherapy, and the sensitivity of targeted drugs in high- and low-risk groups was determined. IRPS can be used to predict the prognosis of OS patients, and provide therapeutic responsiveness to immunotherapy and targeted therapy.

Establishment and Characterization of NCC-MFS5-C1: A Novel Patient-Derived Cell Line of Myxofibrosarcoma

Myxofibrosarcoma (MFS) is a highly aggressive malignancy with complex karyotypes and a postoperative recurrence tendency, owing to its strong invasiveness. Although systemic chemotherapy is considered in patients with unresectable MFS, the efficacy of conventional chemotherapy is hitherto unclear. Recently, drug screening analysis using a large number of tumor cell lines has been attempted to discover novel therapeutic candidate drugs for common cancers. However, the number of MFS cell lines is extremely small because of its low incidence-this hinders the conduction of screening studies and slows down the development of therapeutic drugs. To overcome this problem, we established a novel MFS cell line, NCC-MFS5-C1, which was shown to harbor typical MFS genetic abnormalities and thus had useful properties for in vitro studies. We conducted the largest integrated screening analysis of 210 drugs using NCC-MFS5-C1 cells along with four MFS cell lines, which we previously reported. Bortezomib (a proteasome inhibitor) and romidepsin (a histone deacetylase inhibitor) showed stronger antitumor effects than the standard drug, doxorubicin. Therefore, the NCC-MFS5-C1 cell line can potentially contribute to elucidating MFS pathogenesis and developing a novel MFS treatment.

Report of two primary renal tumors with myxoid features. Differential diagnosis between benign and malignant entities

Renal mesenchymal neoplasms are rare entities which can have a benign or a malignant behavior. Herein we describe two renal mesenchymal tumors with myxoid stroma, investigating the wide spectrum of differential diagnosis. With our first case we considered some benign entities such as myxoma, myxoid leiomyoma, and mixed epithelial and stromal tumor; with our second case we considered some sarcomas with myxoid features such as myxofibrosarcoma, low-grade fibromyxoid sarcoma, dedifferentiated liposarcoma, and myxoid liposarcoma. During the diagnostic process, it is important to integrate histopathological, immunohistochemical, and molecular data in order to avoid misdiagnosis. We concluded our second case report was a myxofibrosarcoma grade 1. To the best of our knowledge, we described the fourth primary renal myxofibrosarcoma reported in literature.

Prognostic value of CD34 expression status in patients with myxofibrosarcomas and undifferentiated pleomorphic sarcomas

It is controversial whether patients with myxofibrosarcomas (MFSs) have better prognoses than those with undifferentiated pleomorphic sarcomas (UPSs). No useful prognostic factors have been established to date. We therefore aimed to evaluate the prognostic value of CD34 expression status in 192 patients with MFSs and UPSs. Using the log-rank test, we showed that patients with MFSs had a significantly better overall survival than did those with UPSs when defining the former as having a > 10% myxoid component (p = 0.03), but not when defining it as having a > 50% myxoid component (p = 0.1). Under the definition of MFSs as > 10% myxoid component, the log-rank test revealed that the diagnosis of the UPS and the CD34 loss (p < 0.001) were significant adverse predictors of overall survival. As per the Cox model, the CD34 loss remained an independent prognostic factor (hazard ratio = 3.327; 95% confidence interval 1.334-8.295), while the diagnosis of the UPS was a nonsignificant confounding factor (hazard ratio = 1.084; 95% confidence interval 0.679-1.727). In conclusion, CD34 expression status is a useful prognostic factor in patients with MFS and UPS, and it should be incorporated into grading systems that are used to predict outcomes.

Molecular Determinants of Soft Tissue Sarcoma Immunity: Targets for Immune Intervention

Soft tissue sarcomas (STSs) are a family of rare malignant tumors encompassing more than 80 histologies. Current therapies for metastatic STS, a condition that affects roughly half of patients, have limited efficacy, making innovative therapeutic strategies urgently needed. From a molecular point of view, STSs can be classified as translocation-related and those with a heavily rearranged genotype. Although only the latter display an increased mutational burden, molecular profiles suggestive of an “immune hot” tumor microenvironment are observed across STS histologies, and response to immunotherapy has been reported in both translocation-related and genetic complex STSs. These data reinforce the notion that immunity in STSs is multifaceted and influenced by both genetic and epigenetic determinants. Cumulative evidence indicates that a fine characterization of STSs at different levels is required to identify biomarkers predictive of immunotherapy response and to discover targetable pathways to switch on the immune sensitivity of “immune cold” tumors. In this review, we will summarize recent findings on the interplay between genetic landscape, molecular profiling and immunity in STSs. Immunological and molecular features will be discussed for their prognostic value in selected STS histologies. Finally, the local and systemic immunomodulatory effects of the targeted drugs imatinib and sunitinib will be discussed.

Characterization of PD-1/PD-L1 immune checkpoint expression in soft tissue sarcomas

Inhibitors of the programmed death-1/programmed death-ligand 1 (PD-1/PD-L1) immune checkpoint system are used for treating various malignancies. However, evidence on their use in soft tissue sarcomas (STS) is limited. This study aimed to retrospectively investigate the relationship between the expression of PD-1/PD-L1 and related antigens in STS, and their association with clinical characteristics. Immunostaining for CD4, CD8, PD-1, PD-L1, IL-2, and IFN-γ was performed using pathological specimens harvested at the time of biopsy from 10 patients with undifferentiated pleomorphic sarcoma (UPS), nine with myxofibrosarcoma (MFS), and three with malignant peripheral nerve sheath tumor (MPNST) who were treated at our hospital. Subsequently, the positive immunostaining cell rates were calculated. We also examined the correlation between each immune positive cell rate and age, tissue grade, size, and maximum standardized uptake (SUV-max) values. The 3-year event-free survival (EFS) and overall survival (OS) rates were compared between the positive and negative groups (positive rate >10%; negative <10%) for various immune stains. The positive rates were also compared between the presence and absence of events groups. There was positive staining for the immune checkpoint molecules in every STS type except for PD-1 in MPNST. CD4, CD8, and PD-1 stained lymphocytes in close proximity to the tumor in adjacent tissue sections. A positive correlation was observed between the positive cell rates of each immune component including inflammatory cytokines such as IL-2 and IFN-γ. Additionally, the clinical features positively correlated with the positive PD-1/PD-L1 expression rates. No significant differences in the 3-EFS and OS rates were observed between the PD-1/PD-L1 positive and negative groups. Our results suggest that an inducible immune checkpoint mechanism may be involved in UPS, MFS, and MPNST.

DNA methylation-based profiling of bone and soft tissue tumours: a validation study of the 'DKFZ Sarcoma Classifier'

Diagnosing bone and soft tissue neoplasms remains challenging because of the large number of subtypes, many of which lack diagnostic biomarkers. DNA methylation profiles have proven to be a reliable basis for the classification of brain tumours and, following this success, a DNA methylation-based sarcoma classification tool from the Deutsches Krebsforschungszentrum (DKFZ) in Heidelberg has been developed. In this study, we assessed the performance of their classifier on DNA methylation profiles of an independent data set of 986 bone and soft tissue tumours and controls. We found that the 'DKFZ Sarcoma Classifier' was able to produce a diagnostic prediction for 55% of the 986 samples, with 83% of these predictions concordant with the histological diagnosis. On limiting the validation to the 820 cases with histological diagnoses for which the DKFZ Classifier was trained, 61% of cases received a prediction, and the histological diagnosis was concordant with the predicted methylation class in 88% of these cases, findings comparable to those reported in the DKFZ Classifier paper. The classifier performed best when diagnosing mesenchymal chondrosarcomas (CHSs, 88% sensitivity), chordomas (85% sensitivity), and fibrous dysplasia (83% sensitivity). Amongst the subtypes least often classified correctly were clear cell CHSs (14% sensitivity), malignant peripheral nerve sheath tumours (27% sensitivity), and pleomorphic liposarcomas (29% sensitivity). The classifier predictions resulted in revision of the histological diagnosis in six of our cases. We observed that, although a higher tumour purity resulted in a greater likelihood of a prediction being made, it did not correlate with classifier accuracy. Our results show that the DKFZ Classifier represents a powerful research tool for exploring the pathogenesis of sarcoma; with refinement, it has the potential to be a valuable diagnostic tool.

Toward a Personalized Therapy in Soft-Tissue Sarcomas: State of the Art and Future Directions

Soft-tissue sarcomas are rare tumors characterized by pathogenetic, morphological, and clinical intrinsic variability. Median survival of patients with advanced tumors are usually chemo- and radio-resistant, and standard treatments yield low response rates and poor survival results. The identification of defined genomic alterations in sarcoma could represent the premise for targeted treatments. Summarizing, soft-tissue sarcomas can be differentiated into histotypes with reciprocal chromosomal translocations, with defined oncogenic mutations and complex karyotypes. If the latter are improbably approached with targeted treatments, many suggest that innovative therapies interfering with the identified fusion oncoproteins and altered pathways could be potentially resolutive. In most cases, the characteristic genetic signature is discouragingly defined as "undruggable", which poses a challenge for the development of novel pharmacological approaches. In this review, a summary of genomic alterations recognized in most common soft-tissue sarcoma is reported together with current and future therapeutic opportunities.

Germinal GLT8D1, GATAD2A and SLC25A39 mutations in a patient with a glomangiopericytal tumor and five different sarcomas over a 10-year period

Soft tissue sarcoma represents about 1% of all adult cancers. Occurrence of multiple sarcomas in a same individual cannot be fortuitous. A 72-year-old patient had between 2007 and 2016 a glomangiopericytal tumor of the right forearm and a succession of sarcomas of the extremities: a leiomyosarcoma of the left buttock, a myxofibrosarcoma (MFS) of the right forearm, a MFS of the left scapula, a left latero-thoracic MFS and two undifferentiated sarcomas on the left forearm. Pathological examination of the six locations was not in favor of disease with local/distant recurrences but could not confirm different diseases. An extensive molecular analysis including DNA-array, RNA-sequencing and DNA-Sanger-sequencing, was thus performed to determine the link between them. The genomic profile of the glomangiopericytal tumor and the six sarcomas revealed that five sarcomas were different diseases and one was the local recurrence of the glomangiopericytal tumor. While the chromosomal alterations in the six tumors were different, a common somatic CDKN2A/CDKN2B deletion was identified. RNA-sequencing of five tumors identified mutations in GLT8D1, GATAD2A and SLC25A39 in all samples. The germline origin of these mutations was confirmed by Sanger-sequencing. Innovative molecular analysis methods have made possible a better understanding of the complex tumorigenesis of multiple sarcomas.

Gene expression profiles for an immunoscore model in bone and soft tissue sarcoma

Background: Immune infiltration is a prognostic marker to clinical outcomes in various solid tumors. However, reports that focus on bone and soft tissue sarcoma are rare. The study aimed to analyze and identify how immune components influence prognosis and develop a novel prognostic system for sarcomas.

Methods: We retrieved the gene expression data from 3 online databases (GEO, TCGA, and TARGET). The immune fraction was estimated using the CIBERSORT algorithm. After that, we re-clustered samples by K-means and constructed immunoscore by the least absolute shrinkage and selection operator (LASSO) Cox regression model. Next, to confirm the prognostic value, nomograms were constructed.

Results: 334 samples diagnosed with 8 tumor types (including osteosarcoma) were involved in our analysis. Patients were next re-clustered into three subgroups (OS, SAR1, and SAR2) through immune composition. Survival analysis showed a significant difference between the two soft tissue groups: patients with a higher proportion of CD8+ T cells, macrophages M1, and mast cells had favorable outcomes (p=0.0018). Immunoscore models were successfully established in OS and SAR2 groups consisting of 12 and 9 cell fractions, respectively. We found immunosocre was an independent factor for overall survival time. Patients with higher immunoscore had poor prognosis (p<0.0001). Patients with metastatic lesions scored higher than those counterparts with localized tumors (p<0.05).

Conclusions: Immune fractions could be a useful tool for the classification and prognosis of bone and soft tissue sarcoma patients. This proposed immunoscore showed a promising impact on survival prediction.

Potential application of genomic profiling for the diagnosis and treatment of patients with sarcoma

Sarcomas represent a heterogeneous group of mesenchymal malignancies arising at various locations in the soft tissue and bone. Though a rare disease, sarcoma affects ~200,000 patients worldwide every year. The prognosis of patients with sarcoma is poor, and targeted therapy options are limited; therefore, accurate diagnosis and classification are essential for effective treatment. Sarcoma samples were acquired from 199 patients, in which TP53 (39.70%, 79/199), CDKN2A (19.10%, 38/199), CDKN2B (15.08%, 30/199), KIT (14.07%, 28/199), ATRX (10.05%, 20/199) and RB1 (10.05%, 20/199) were identified as the most commonly mutated genes (>10% incidence). Among 64 soft-tissue sarcomas that were unclassified by immunohistochemistry, 15 (23.44%, 15/64) were subsequently classified using next-generation sequencing (NGS). For the most part, the sarcoma subtypes were evenly distributed between male and female patients, while a significant association with sex was detected in leiomyosarcomas. Statistical analysis showed that osteosarcoma, Ewing's sarcoma, gastrointestinal stromal tumors and liposarcoma were all significantly associated with the patient age, and that angiosarcoma was significantly associated with high tumor mutational burden. Furthermore, serially mutated genes associated with myxofibrosarcoma, gastrointestinal stromal tumor, osteosarcoma, liposarcoma, leiomyosarcoma, synovial sarcoma and Ewing's sarcoma were identified, as well as neurotrophic tropomyosin-related kinase (NTRK) fusions of IRF2BP2-NTRK1, MEF2A-NTRK3 and ITFG1-NTRK3. Collectively, the results of the present study suggest that NGS-targeting provides potential new biomarkers for sarcoma diagnosis, and may guide more precise therapeutic strategies for patients with bone and soft-tissue sarcomas.

Development and validation of a prognostic nomogram for predicting the overall survival of myxofibrosarcoma patients: a large population-based study

Background

Although some studies have explored prognostic factors of myxofibrosarcoma (MFS), the sample sizes were small, generally fewer than 100 patients. There is still no effective prognostic model for MFS patients based on a large population and comprehensive factors. The present study was designed to establish and validate a large population-based, clinically relevant prognostic nomogram for predicting 3- and 5-year overall survival (OS) in patients with MFS.

Methods

We identified patients with MFS (ICD-O-3 code: 8811/3) who were diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results database and separated them into training and validation cohorts (7:3 ratio). Survival was described using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were used to identify prognostic factors of survival. An individual nomogram was established to predict OS at 3 and 5 years in MFS patients. The discriminative ability and predictive accuracy of the nomogram were compared to those of the traditional American Joint Committee on Cancer (AJCC) staging system in the training and validation cohorts. Finally, MFS patients were divided into two subgroups based on the prognostic index (PI) score of the nomogram, and the survival outcomes of the subgroups were compared.

Results

A total of 1,270 patients were included. Age at diagnosis, total number of in situ or malignant tumors, tumor size, tumor site, tumor extension, AJCC stage, surgical status, chemotherapy, and radiotherapy were the independent predictors of survival and were included in the nomogram. The nomogram had C-indexes of 0.806 in the training cohort and 0.783 in the validation cohort, which were greater than those of the sixth edition of the AJCC staging system (training cohort, 0.669 and validation cohort, 0.674). Decision curve analysis (DCA) revealed that the nomogram was useful with high clinical net benefits. Survival outcomes were significantly different between the different risk subgroups (P<0.001).

Conclusions

A novel nomogram based on a large population was constructed to evaluate survival outcomes for MFS. Its predictive efficacy was markedly superior than that of the traditional sixth edition of the AJCC staging system.

A rare multiple primary sarcomatoid carcinoma (SCA) of small intestine harboring driver gene mutations: a case report and a literature review

Primary sarcomatoid carcinoma (SCA) is a type of rare tumor consisting of both malignant epithelial and mesenchymal components. Only 32 cases of SCA of the small bowel have been reported in the literature to date. Due to its rarity and complexity, this cancer has not been genetically studied and its diagnosis and treatment remain difficult. Here we report a 54-year-old male underwent emergency surgical resection in the small intestine due to severe obstruction and was diagnosed with multiple SCA based on postoperative pathological examination. Over 100 polypoid tumors scattered along his whole jejunum and proximal ileum. Chemotherapy (IFO+Epirubicin) was performed after surgery while the patient died two months after the surgery due to severe malnutrition. Whole-exome sequencing was performed for the tumor tissue with normal tissue as the control. Important cancer-related gene mutations, including KRAS (c.37G>T, p.G13C), TP53 (c.871A>T, p.K291*), EGFR (c.1351C>T, p.R451C), and CDKN2A (c.104_138del, p.G35fs), were found among 286 nonsynonymous somatic mutations (SNV and Indel). Copy-number amplified genes mainly gathered in chromosome 6, 7, 16 and 20. Mutation clustering analysis showed that main genetic abnormalities included DNA methylation, DNA alkylation, cellular homeostasis, and shared similarities with melanoma, glioma, prostate cancer, bladder cancer, non-small cell lung cancer, and pancreatic cancer. In summary, the genomic features of the small intestine SCA were explored at whole-exome level for the first time, and over 200 somatic mutations were identified in the tumor tissue. Key tumor driver gene mutations were revealed, as well as several aberrant functional pathways. These results contribute to further understanding of the pathogenesis and molecular mechanism of this rare tumor.

RSF1 requires CEBP/β and hSNF2H to promote IL-1β-mediated angiogenesis: the clinical and therapeutic relevance of RSF1 overexpression and amplification in myxofibrosarcomas

Myxofibrosarcoma is genetically complex and lacks effective nonsurgical treatment strategies; thus, elucidation of novel molecular drivers is urgently needed. Reanalyzing public myxofibrosarcoma datasets, we identified mRNA upregulation and recurrent gain of RSF1 and characterized this chromatin remodeling gene. Myxofibrosarcoma cell lines were employed to elucidate the oncogenic mechanisms of RSF1 by genetic manipulation and two IL-1β-neutralizing antibodies (RD24, P2D7KK), highlighting the regulatory basis and targetability of downstream IL-1β-mediated angiogenesis. Tumor samples were assessed for RSF1, IL-1β, and microvascular density (MVD) by immunohistochemistry and for RSF1 gene status by FISH. In vivo, RSF1-silenced and P2D7KK-treated xenografts were analyzed for tumor-promoting effects and the IL-1β-linked therapeutic relevance of RSF1, respectively. In vitro, RSF1 overexpression promoted invasive and angiogenic phenotypes with a stronger proangiogenic effect. RT-PCR profiling identified IL1B as a top-ranking candidate upregulated by RSF1. RSF1 required hSNF2H and CEBP/β to cotransactivate the IL1B promoter, which increased the IL1B mRNA level, IL-1β secretion and angiogenic capacity. Angiogenesis induced by RSF1-upregulated IL-1β was counteracted by IL1B knockdown and both IL-1β-neutralizing antibodies. Clinically, RSF1 overexpression was highly associated with RSF1 amplification, IL-1β overexpression, increased MVD and higher grades (all P ≤ 0.01) and independently predicted shorter disease-specific survival (P = 0.019, hazard ratio: 4.556). In vivo, both RSF1 knockdown and anti-IL-1β P2D7KK (200 μg twice weekly) enabled significant growth inhibition and devascularization in xenografts. In conclusion, RSF1 overexpression, partly attributable to RSF1 amplification, contributes a novel proangiogenic function by partnering with CEBP/β to cotransactivate IL1B, highlighting its prognostic, pathogenetic, and therapeutic relevance in myxofibrosarcomas.

Genome wide methylation profiling of selected matched soft tissue sarcomas identifies methylation changes in metastatic and recurrent disease

In this study we used the Illumina Infinium Methylation array to investigate in a cohort of matched archival human tissue samples (n = 32) from 14 individuals with soft tissue sarcomas if genome-wide methylation changes occur during metastatic and recurrent (Met/Rec) disease. A range of sarcoma types were selected for this study: leiomyosarcoma (LMS), myxofibrosarcoma (MFS), rhabdomyosarcoma (RMS) and synovial sarcoma (SS). We identified differential methylation in all Met/Rec matched samples, demonstrating that epigenomic differences develop during the clonal evolution of sarcomas. Differentially methylated regions and genes were detected, not been previously implicated in sarcoma progression, including at PTPRN2 and DAXX in LMS, WT1-AS and TNXB in SS, VENTX and NTRK3 in pleomorphic RMS and MEST and the C14MC / miR-379/miR-656 in MFS. Our overall findings indicate the presence of objective epigenetic differences across primary and Met/Rec human tissue samples not previously reported.

Adult genitourinary sarcoma: The era of optional chemotherapeutic agents for soft tissue sarcoma

OBJECTIVE

To report our institutional experience with treatment of primary genitourinary soft tissue sarcoma.

METHODS

We retrospectively reviewed the medical records of adult soft tissue sarcoma patients treated between March 2005 and May 2019. The primary tumor sites included the prostate, kidney, urinary bladder and the paratesticular structures.

RESULTS

A total of 19 patients - 16 men (84%) and three women (16%) - were enrolled in the study. The median age was 41 years (range 20-79 years). The most common primary site was the prostate (in eight patients; 42%), and prostatic sarcoma patients were younger than patients with sarcomas of other origins. The most common histological subtype was leiomyosarcoma (in five patients; 26%). The overall survival rates after 1, 3 and 5 years were 61.5%, 34.4% and 25.8%, respectively. The median survival time was 20.7 months (95% confidence interval 5.9-35.5 months). Univariate analysis showed that an absence of metastasis at diagnosis and complete surgical resection were predictive of favorable survival. In the chemotherapy group, the objective response rate was 20.5%. Pazopanib was administered to nine patients in the late-line setting, and the objective response rate was 11.1%; six grade ≥3 adverse events were observed in three patients.

CONCLUSIONS

Inoperable metastatic genitourinary soft tissue sarcoma remains difficult to treat, as previously reported. Further investigation on this malignancy, including optimization of currently available antitumor drugs and the development of novel therapeutic agents, is required.

OSmfs: An Online Interactive Tool to Evaluate Prognostic Markers for Myxofibrosarcoma

Myxofibrosarcoma is a complex genetic disease with poor prognosis. However, more effective biomarkers that forebode poor prognosis in Myxofibrosarcoma remain to be determined. Herein, utilizing gene expression profiling data and clinical follow-up data of Myxofibrosarcoma cases in three independent cohorts with a total of 128 Myxofibrosarcoma samples from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases, we constructed an easy-to-use web tool, named Online consensus Survival analysis for Myxofibrosarcoma (OSmfs) to analyze the prognostic value of certain genes. Through retrieving the database, users generate a Kaplan–Meier plot with log-rank test and hazard ratio (HR) to assess prognostic-related genes or discover novel Myxofibrosarcoma prognostic biomarkers. The effectiveness and availability of OSmfs were validated using genes in ever reports predicting the prognosis of Myxofibrosarcoma patients. Furthermore, utilizing the cox analysis data and transcriptome data establishing OSmfs, seven genes were selected and considered as more potentially prognostic biomarkers through overlapping and ROC analysis. In conclusion, OSmfs is a promising web tool to evaluate the prognostic potency and reliability of genes in Myxofibrosarcoma, which may significantly contribute to the enrichment of novelly potential prognostic biomarkers and therapeutic targets for Myxofibrosarcoma.

A Rapid and Cost-Effective Gene Expression Assay for the Diagnosis of Well-Differentiated and Dedifferentiated Liposarcomas

Histologic examination neither reliably distinguishes benign lipomas from atypical lipomatous tumor/well-differentiated liposarcoma, nor dedifferentiated liposarcoma from other pleomorphic sarcomas, entities with different prognoses and management. Molecular confirmation of pathognomonic 12q13-15 amplifications leading to MDM2 overexpression is a diagnostic gold standard. Currently the most commonly used assay for this purpose is fluorescence in situ hybridization (FISH), but this is labor intensive. This study assessed whether newer NanoString-based technology could allow for more rapid and cost-efficient diagnosis of liposarcomas on standard formalin-fixed tissues through gene expression. Leveraging large-scale transcriptome data from The Cancer Genome Atlas, 20 genes were identified, most from the 12q13-15 amplicon, that distinguish dedifferentiated liposarcoma from other sarcomas and can be measured within a single NanoString assay. Using 21 cases of histologically ambiguous low-grade adipocytic tumors with available MDM2 amplification status, a machine learning-based analytical pipeline was built that assigns a given sample as negative or positive for liposarcoma based on quantitative gene expression. The effectiveness of the assay was validated on an independent set of 100 sarcoma samples (including 40 incident prospective cases), where histologic examination was considered insufficient for clinical diagnosis. The NanoString assay had a 93% technical success rate, and an accuracy of 97.8% versus an MDM2 amplification FISH gold standard. NanoString had a considerably faster turnaround time and was cheaper than FISH.

A novel mutation of the MEN1 gene in a patient with multiple endocrine neoplasia type 1 and recurrent fibromyxoid sarcoma - a case report

Background

Multiple endocrine neoplasia type 1 (MEN1) syndrome is usually accompanied by endocrine tumors, but non-endocrine tumors can occur as well. However, the coexistence of MEN1 syndrome and malignant tumor such as low-grade fibromyxoid sarcoma has not been described in the literature. Moreover, the MEN1 gene mutations have not been identified in patients with fibromyxoid sarcoma, so far.

Case presentation

We present a patient with a long-year endocrine follow-up due to multiple endocrine tumors. During his lifespan, he has been surgically treated for pancreatic gastrinoma, parathyroid hyperplasia, atypical pulmonary carcinoid, various benign mesenchymal, and several skin tumors (basocellular tumor, lipomas, and fibromas) which raised a high clinical suspicion of MEN1 syndrome but the patient refused genetic testing. Recently, he developed a novel malignant tumor – recurrent low-grade fibromyxoid sarcoma of the trunk and extremities with multiple subsequent operations. The patient eventually accepted the genetic testing which proved him to be a carrier of a novel mutation in the MEN1 gene.

Conclusions

Unlike some other syndromes where a genetic mutation can predict clinical course, there is no genotype-phenotype correlation in MEN1 syndrome. Therefore, these patients require lifelong and multidisciplinary surveillance, not only for typical endocrine and benign non-endocrine tumors but also for diverse and even more malignant forms. The atypical clinical presentation should pose suspicion about new gene mutation and serve as a warning in the further follow-up.

Establishment and characterization of NCC-MFS2-C1: a novel patient-derived cancer cell line of myxofibrosarcoma

Myxofibrosarcoma (MFS) is among the most aggressive and complex sarcoma types that require novel therapeutic approaches for improved clinical outcomes. MFS displays highly complex karyotypes, and frequent alterations in p53 signaling and cell cycle checkpoint genes as well as loss-of-function mutations in NF1 and PTEN have been reported. The effects of radiotherapy and chemotherapy on MFS are limited, and complete surgical resection is the only curative treatment. Thus, the development of novel therapeutic strategies for MFS has long been long desired for MFS. Patient-derived cell lines are an essential tool for basic and translational research in oncology. However, public cell banks provide only a limited number of MFS cell lines. In this study, we aimed to develop a novel patient-derived MFS cell line, which was established from the primary tumor tissue of a 71-year-old male patient with MFS and was named NCC-MFS2-C1. A single-nucleotide polymorphism assay revealed that NCC-MFS2-C1 cells exhibited gain and loss of genetic loci. NCC-MFS2-C1 cells were maintained as a monolayer culture for over 24 passages for 10 months. The cells exhibited spindle-like morphology, continuous growth, and capacity for spheroid formation and invasion. Screening of 213 anticancer agents revealed that bortezomib, gemcitabine, romidepsin, and topotecan at low concentrations inhibited the proliferation of NCC-MFS2-C1 cells. In conclusion, we established a novel MFS cell line, NCC-MFS2-C1, which can be used for studying the molecular mechanisms underlying tumor development and for the in vitro screening of anti-cancer drugs.

Systemic Inflammation Is Associated with Oncological Outcome in Patients with High-Grade Myxofibrosarcoma of the Extremities: A Retrospective Analysis

BACKGROUND

The aim of this retrospective study is to verify whether preoperative systemic inflammatory markers (serum C-reactive protein [CRP] and neutrophil-lymphocyte ratio [NLR]) can help in predicting the disease-specific survival (DSS) and local recurrence (LR) rate in adult patients affected by localized myxofibrosarcoma (MFS) of the extremities.

METHODS

We reviewed 126 adult patients with primary, localized MFS of the limbs. We analyzed DSS and LR.

RESULTS

Median age at the time of surgery was 68 years (range 19-92). Median CRP was 0.4 mg/dL and median NLR was 2.8. A worse DSS was found in patients who had preoperative CRP >0.5 mg/dL (p = 0.002) and in those with NLR >3.5 (p < 0.001). In multivariate analysis, tumor size and grade as well as preoperative CRP values and NLR were confirmed to be prognostic factors in terms of DSS. An increased risk of LR was found in multivariate analysis in patients with a tail sign and with high gadolinium enhancement at preoperative MRI.

CONCLUSIONS

Patients with high preoperative CRP and NLR levels, as well as large and high-grade tumors, might be considered as candidates for additional, more aggressive treatment approaches or more stringent follow-up schedules.

The Biology of Myxofibrosarcoma: State of the Art and Future Perspectives

BACKGROUND

Myxofibrosarcoma (MFS) is among the most highly complex sarcoma types. Molecular cytogenetic studies have identified a high level of genomic complexity.

SUMMARY

This review provides an update of the current research related to MFS, with particular emphasis on emerging mechanisms of tumorigenesis and their potential therapeutic impact. Many novel possible molecular markers have been identified, not only for prognostication in MFS, but also to serve as possible therapeutic targets, and thereby improve clinical outcomes. However, the molecular pathogenesis of MFS remains incompletely understood. Key Messages: Patients suffering from advanced MFS might benefit from expanded molecular evaluation in order to detect specific expression profiles and identify drug-able targets. Moreover, immunotherapy represents an intriguingly perspective due to the presence of "T-cell inflamed" tumor microenvironment.