Current status of engineered T-cell therapy for synovial sarcoma

Advances of SS18-SSX fusion gene in synovial sarcoma: Emerging novel functions and therapeutic potentials

Synovial sarcoma is a rare type of soft tissue sarcoma that primarily affects adolescents and young adults, featured by aggressive behavior and a high potential for metastasis. Genetically, synovial sarcoma is defined by the fusion oncogene SS18-SSX arising from the translocation of t(X;18)(p11;q11). SS18-SSX fusion gene is the major driver of the oncogenic event in synovial sarcoma. SS18-SSX fusion protein, while not containing any DNA-binding motifs, binds to the SWI/SNF (BAF) complex, a major epigenetic regulator, leading to the disruption of gene expression which results in tumor initiation and progression. Emerging studies on the molecular mechanisms of SS18-SSX associated signaling pathway hold promise for developments in diagnosis and treatments. Advanced diagnostic methods facilitate early and precise detection of the tumor, enabling disease monitoring and prognostic improvements. Treatment of synovial sarcoma typically comprises local surgery, radiotherapy and chemotherapy, while novel managements such as immunotherapy, targeted therapies and epigenetic modifiers are explored. This review focuses on the recent studies of SS18-SSX fusion gene, epigenetic landscape, signaling pathways, diagnostic techniques, and relevant therapeutic advances, aiming to inhibit the oncogenic processes and improve outcomes for patients with synovial sarcoma.

Synovial sarcoma: characteristics, challenges, and evolving therapeutic strategies

Synovial sarcoma (SS) is a rare and aggressive disease that accounts for 5%-10% of all soft tissue sarcomas. Although it can occur at any age, it typically affects younger adults and children, with a peak incidence in the fourth decade of life. In >95% of cases, the oncogenic driver is a translocation between chromosomes X and 18 that leads to the formation of the SS18::SSX fusion oncogenes. Early and accurate diagnosis is often a challenge; optimal outcomes are achieved by referral to a specialist center for diagnosis and management by a multidisciplinary team as soon as SS is suspected. Surgery with or without radiotherapy and/or chemotherapy can be effective in localized disease, especially in children. However, the prognosis in the advanced stages is poor, with treatment strategies that have relied heavily on traditional cytotoxic chemotherapies. Therefore, there is an unmet need for novel effective management strategies for advanced disease. An improved understanding of disease pathology and its molecular basis has paved the way for novel targeted agents and immunotherapies that are being investigated in clinical trials. This review provides an overview of the epidemiology and characteristics of SS in children and adults, as well as the patient journey from diagnosis to treatment. Current and future management strategies, focusing particularly on the potential of immunotherapies to improve clinical outcomes, are also summarized.

Synovial sarcoma of female urethra: a case report and review of the literature

Synovial sarcoma (SS) is a rare malignant soft tissue sarcoma that originates from primitive mesenchymal cells with epithelial differentiation potential. It is most commonly found in the limbs and trunk. In the urinary system, it is mostly found in the kidneys. However, synovial sarcomas originating from the external urethra are extremely rare. Only one case of synovial sarcoma arising from the vulvar urethral orifice has been reported previously, and we report a second case of synovial sarcoma of the urethral orifice. In addition, a total of 16 vulvar synovial sarcomas were identified and the literature are analyzed in this report reviews from 1966 to the present.

Relapsed Synovial Sarcoma: Treatment Options

OPINION STATEMENT

Synovial sarcoma (SS) is a fusion-driven subtype of sarcoma that is a more chemo-sensitive subtype of soft tissue sarcoma. While chemotherapy options are currently standard of care, our fundamental understanding of the biology of SS is driving new therapies. We will review the current standard of care, as well as the current therapies showing promise in a clinical trial. It is our hope that by encouraging participation in clinical trials, the fundamental therapies available for SS will change the current treatment paradigm.

What's the latest with investigational drugs for soft tissue sarcoma?

INTRODUCTION

Despite extensive research undertaken in the past 20-30 years, the treatment for soft tissue sarcoma (STS) has remained largely the same, with anthracycline-based chemotherapy remaining the first choice for treating advanced or metastatic STS.

AREAS COVERED

This review focuses on newly approved drugs for STS and current research directions, including recent results of late-phase trials in patients with STS. We cover several different histological subtypes, and we discuss the role of adoptive cell transfer (ACT) therapies for the treatment of synovial and myxoid/round cell (high-grade myxoid) liposarcoma, one of the most promising areas of treatment development to date. We searched clinicaltrials.gov and pubmed.ncbi.nih.gov, as well as recent year proceedings from the annual conferences of the American Society of Clinical Oncology (ASCO), European Society for Medical Oncology (ESMO), and Connective Tissue Oncology Society (CTOS).

EXPERT OPINION

Immune-oncology drugs (IOs) show promise in certain subtypes of STS, but it is recognized that PD-1/PD-L1 axis inhibition is not enough on its own. Better trial stratifications based on the molecular categorization of different subtypes of STS are needed, and more evidence suggests that 'one size fits all' treatment is no longer sustainable in this heterogeneous and aggressive group of tumors.

Biomarker correlates with response to NY-ESO-1 TCR T cells in patients with synovial sarcoma

Autologous T cells transduced to express a high affinity T-cell receptor specific to NY-ESO-1 (letetresgene autoleucel, lete-cel) show promise in the treatment of metastatic synovial sarcoma, with 50% overall response rate. The efficacy of lete-cel treatment in 45 synovial sarcoma patients (NCT01343043) has been previously reported, however, biomarkers predictive of response and resistance remain to be better defined. This post-hoc analysis identifies associations of response to lete-cel with lymphodepleting chemotherapy regimen (LDR), product attributes, cell expansion, cytokines, and tumor gene expression. Responders have higher IL-15 levels pre-infusion (p = 0.011) and receive a higher number of transduced effector memory (CD45RA- CCR7-) CD8 + cells per kg (p = 0.039). Post-infusion, responders have increased IFNγ, IL-6, and peak cell expansion (p < 0.01, p < 0.01, and p = 0.016, respectively). Analysis of tumor samples post-treatment illustrates lete-cel infiltration and a decrease in expression of macrophage genes, suggesting remodeling of the tumor microenvironment. Here we report potential predictive and pharmacodynamic markers of lete-cel response that may inform LDR, cell dose, and strategies to enhance anticancer efficacy.

Biomarkers predictive of response to T cell therapy remain to be better defined. This study identifies potential predictive and pharmacodynamic markers of response to NY-ESO-1 T-cell therapy in a solid tumor that may inform lymphodepletion, cell dose, and strategies to enhance anticancer efficacy.

miRNAs as Biomarkers and Possible Therapeutic Strategies in Synovial Sarcoma

Synovial sarcoma (SS) is an epithelial-differentiated malignant stromal tumor that has the highest incidence in young people and can occur almost anywhere in the body. Many noncoding RNAs are involved in the occurrence, development, or pathogenesis of SS. In particular, the role of MicroRNAs (miRNAs) in SS is receiving increasing attention. MiRNA is a noncoding RNA abundant in cells and extracellular serums. Increasing evidence suggests that miRNA has played a significant role in the incidence and development of tumors in recent years, including sarcomas. Previous studies show that various sarcomas have their unique miRNA expression patterns and that various miRNA expression profiles can illustrate the classes of miRNAs that may elicit cancer-relevant activities in specific sarcoma subtypes. Furthermore, SS has been reported to have the most number of differentially expressed miRNAs, which indicated that miRNA is linked to SS. In fact, according to many publications, miRNAs have been shown to have a role in the development and appearance of SS in recent years, according to many publications. Since many studies showing that various miRNAs have a role in the development and appearance of SS in recent years have not been systematically summarized, we summarize the recent studies on the relationship between miRNA and SS in this review. For example, miR-494 promotes the development of SS via modulating cytokine gene expression. The role of miR-494-3p as a tumor suppressor is most likely linked to the CXCR4 (C-X-C chemokine receptor 4) regulator, although the exact mechanism is unknown. Our review aims to reveal in detail the potential biological value and clinical significance of miRNAs for SS and the potential clinical value brought by the association between SS and miRNAs.

Linking Immunity with Genomics in Sarcomas: Is Genomic Complexity an Immunogenic Trigger?

Sarcomas comprise a collection of highly heterogeneous malignancies that can be grossly grouped in the categories of sarcomas with simple or complex genomes. Since the outcome for most sarcoma patients has barely improved in the last decades, there is an urgent need for improved therapies. Immunotherapy, and especially T cell checkpoint blockade, has recently been a game-changer in cancer therapy as it produced significant and durable treatment responses in several cancer types. Currently, only a small fraction of sarcoma patients benefit from immunotherapy, supposedly due to a general lack of somatically mutated antigens (neoantigens) and spontaneous T cell immunity in most cancers. However, genomic events resulting from chromosomal instability are frequent in sarcomas with complex genomes and could drive immunity in those tumors. Improving our understanding of the mechanisms that shape the immune landscape of sarcomas will be crucial to overcoming the current challenges of sarcoma immunotherapy. This review focuses on what is currently known about the tumor microenvironment in sarcomas and how this relates to their genomic features. Moreover, we discuss novel therapeutic strategies that leverage the tumor microenvironment to increase the clinical efficacy of immunotherapy, and which could provide new avenues for the treatment of sarcomas.

Synovial Sarcoma of Ethmoidal Sinus

Background  Synovial sarcoma is an aggressive soft tissue cancer of extremities mainly and rare in head and neck region, whereas rarest in ethmoidal sinus as only three cases have been reported till date. Case Reports  We managed two cases of synovial sarcoma who presented with nasal obstruction, epistaxis, and swelling around the nasofacial region. Endoscopic nasal biopsy and immunohistochemistry markers confirmed synovial sarcoma in both the cases. While one case was managed by surgery and chemoradiation, the second patient received two cycles of ifosfamide-based chemotherapy and succumbed after 6 weeks of diagnosis. Conclusion  Head and neck sarcomas are aggressive and carry a poor prognosis. Surgical resection with postoperative radiotherapy is the standard treatment. However, they have a high risk of recurrence and hence aggressive management and close follow-up is warranted for the optimal outcome.

Immunotherapy for sarcomas

Sarcomas are a heterogeneous group of malignancies of mesenchymal origin; their molecular and genomic mechanisms differ with regard to histology. These characteristics lead to the presentation of varied immunological profiles based on the tumor microenvironment. Various immunotherapies are considered for the treatment of sarcoma. These treatments are performed either in isolation or in combination with other methods such as cytotoxic chemotherapy or the use of molecular target agents. Among these, two recently emerging immunotherapies include T-cell receptor gene therapy and immune checkpoint inhibitor therapy, which are expected to be effective for many types of sarcoma. A sarcoma with a disease-specific translocation and a limited number of mutations, such as synovial sarcoma, expresses high levels of self-antigens, like the New York esophageal squamous cell carcinoma 1, which has been targeted in T-cell receptor gene therapy. On the other hand, sarcomas with a greater number of mutations, such as undifferentiated pleomorphic sarcomas, myxofibrosarcoma and dedifferentiated liposarcomas, can be good candidates for immune checkpoint inhibitors. Among immune checkpoint inhibitor therapies, programmed cell death-1 blockade (nivolumab and pembrolizumab) and cytotoxic T-lymphocyte-associated antigen 4 blockade (ipilimumab) have been investigated most often in sarcoma. Although the sole use of immune checkpoint inhibitors provides limited efficacy, combined immunotherapy with immune checkpoint inhibitors or molecular target agents, especially antiangiogenic agents, has shown moderate results against some types of sarcoma, such as the alveolar soft part sarcoma. Several clinical trials utilizing immunotherapy, including T-cell receptor gene therapy and immune checkpoint inhibitors, in sarcomas are under progress. By clarifying the tumor microenvironment and biomarker-predictive capacity of immunotherapy in sarcomas, better clinical trials can be designed; this could lead to improved outcomes for immunotherapy in sarcoma.

Soft-tissue Sarcoma of the Hand: Patient Characteristics, Treatment, and Oncologic Outcomes

INTRODUCTION

The aim of this study was to describe patient characteristics, treatment, and oncologic outcomes of soft-tissue sarcomas (STSs) of the hand.

METHODS

Sixty-nine STSs of the hand in adult patients treated at a tertiary referral center were retrospectively included. We describe patient and tumor characteristics along with oncologic outcomes.

RESULTS

Epithelioid sarcoma (23%) was the most common histologic subtype, followed by synovial sarcoma (15%). Of all tumors, 17 (25%) were grade I, 22 (32%) were grade II, and 30 (44%) were grade III. The 5-year disease-free survival for epithelioid sarcomas was 75% with a disease survival of 100%, along with a metastatic rate of 15%. Of the patients with a synovial sarcoma, 40% developed metastases, and the 5-year disease-free survival was 68% and the 5-year disease survival was 73%.

CONCLUSION

Hand STSs are aggressive tumors with a high metastatic potential. Even with adequate oncologic treatment, long-term clinical follow-up (10 years) in these tumors is advised. The treating surgical oncologist should not be deceived by their smaller size.

Correlative Analyses of the SARC028 Trial Reveal an Association Between Sarcoma-Associated Immune Infiltrate and Response to Pembrolizumab

PURPOSE

We recently reported a 17.5% objective RECIST 1.1 response rate in a phase II study of pembrolizumab in patients with advanced sarcoma (SARC028). The majority of responses occurred in undifferentiated pleomorphic sarcoma (UPS) and dedifferentiated liposarcoma (DDLPS). We sought to determine whether we can identify immune features that correlate with clinical outcomes from tumor tissues obtained pre- and on-treatment.

PATIENTS AND METHODS

Pretreatment (n = 78) and 8-week on-treatment (n = 68) tumor biopsies were stained for PD-L1 and multiplex immunofluorescence panels. The density of positive cells was quantified to determine associations with anti-PD-1 response.

RESULTS

Patients that responded to pembrolizumab were more likely to have higher densities of activated T cells (CD8+ CD3+ PD-1+) and increased percentage of tumor-associated macrophages (TAM) expressing PD-L1 pre-treatment compared with non-responders. Pre-treatment tumors from responders also exhibited higher densities of effector memory cytotoxic T cells and regulatory T cells compared with non-responders. In addition, higher density of cytotoxic tumor-infiltrating T cells at baseline correlated with a better progression-free survival (PFS).

CONCLUSIONS

We show that quantitative assessments of CD8+ CD3+ PD-1+ T cells, percentage of TAMs expressing PD-L1, and other T-cell densities correlate with sarcoma response to pembrolizumab and improved PFS. Our findings support that multiple cell types present at the start of treatment may enhance tumor regression following anti-PD-1 therapy in specific advanced sarcomas. Efforts to confirm the activity of pembrolizumab in an expansion cohort of patients with UPS/DDLPS are underway.

Non-gastrointestinal stromal tumours soft tissue sarcomas: an update

Soft tissue sarcomas (STS) encompass a diverse family of neoplasms of mesenchymal origin, marked by significant heterogeneity in terms of physiopathology, molecular characterisation, natural history and response to different therapies. This review aims to summarise the current strategies for the management of patients with STS, including surgery, systemic treatments and radiation therapy, along with considerations applicable to the most frequent subtypes, as well as particularities associated with less common and specific histologies. It also provides insights into upcoming strategies to tackle this challenging group of diseases.

Translocation-Related Sarcomas

Chromosomal translocations are observed in approximately 20% of soft tissue sarcomas (STS). With the advances in pathological examination technology, the identification of translocations has enabled precise diagnoses and classifications of STS, and it has been suggested that the presence of and differences in translocations could be prognostic factors in some translocation-related sarcomas. Most of the translocations in STS were not regarded as targets of molecular therapies until recently. However, trabectedin, an alkylating agent, has shown clinical benefits against translocation-related sarcoma based on a modulation of the transcription of the tumor's oncogenic fusion proteins. Many molecular-targeted drugs that are specific to translocations (e.g., anaplastic lymphoma kinase and tropomyosin kinase related fusion proteins) have emerged. The progress in gene technologies has allowed researchers to identify and even induce new translocations and fusion proteins, which might become targets of molecular-targeted therapies. In this review, we discuss the clinical significance of translocation-related sarcomas, including their diagnoses and targeted therapies.

Systemic Treatment for Adults with Synovial Sarcoma

OPINION STATEMENT

Synovial sarcoma (SS) is a rare, yet highly malignant, type of soft tissue sarcoma (STS), for which survival has not improved significantly during the past years. In this review, we focus on systemic treatment in adults. Compared to other STS, SS are relatively chemosensitive. Ifosfamide and ifosfamide combinations are active in different lines of treatment. In high-risk extremity and chest wall STS, neoadjuvant doxorubicin and ifosfamide has shown as much activity as high-dose ifosfamide. There are indications that combination chemotherapy with doxorubicin and ifosfamide in this setting improves outcome. In the first-line metastatic setting, combination treatment with doxorubicin and ifosfamide is a preferred option in fit patients, while in other patients, sequential doxorubicin and ifosfamide can be considered. In second and later lines, pazopanib and trabectedin have shown activity. Many new approaches to treat metastatic SS are currently under investigation, both preclinical as well as clinical, including other receptor tyrosine kinase inhibitors, epigenetic modulators, compounds interfering with DNA damage response (DDR), and immunotherapy.