Response to anti-PD1 therapy with nivolumab in metastatic sarcomas

FBXO22 is a potential therapeutic target for recurrent chondrosarcoma

Chondrosarcoma (CHS) is a malignant bone tumor with insensitivity to both radiotherapy and chemotherapy, and a high recurrence rate. However, the latent mechanism of recurrent CHS (Re-CHS) remains elusive. Here, we discovered that FBXO22 was highly expressed in clinical samples of Re-CHS. FBXO22 played a significant role in various cancers. However, the role of FBXO22 in Re-CHS remained unclear. Our research demonstrated that suppressing FBXO22 abated the proliferation and migration of CHS cells and facilitated their apoptosis. In addition, suppressing FBXO22 raised the expression of PD-L1 in Re-CHS. All these findings provide new evidence for using FBXO22 and PD-L1 as combined targets to prevent and treat Re-CHS, which may prove to be a novel strategy for immunotherapy of CHS, especially Re-CHS.

Clinical activity of pembrolizumab in refractory MDM2-amplified advanced intimal sarcomas

Intimal sarcoma (InS) is an ultra-rare and aggressive subtype of soft tissue sarcoma (STS). It usually arises in large mediastinal arteries and the heart. In the advanced setting, sequential cytotoxic chemotherapy is often used, mainly based on retrospective studies and case series but with modest benefit. The use of immune checkpoint inhibitors is a promising strategy for some STS, but identifying biomarkers of response remains challenging due to disease rarity and heterogeneity. A reactive and pro-inflammatory tumor microenvironment (TME) is believed to be associated with better outcomes for patients receiving anti-PD-1-based regimens, generating the rationale to explore this strategy in malignancies with this characteristic, such as InS. We report three cases of advanced InS patients experiencing partial response to pembrolizumab-based therapy despite low tumor mutational burden and absence of mismatch-repair deficiency. We hypothesize that TME-related characteristics such as PD-L1 expression and the presence of tertiary lymphoid structures might explain this phenomenon.

New advances in the treatment of chondrosarcoma under the PD-1/PD-L1 pathway

ABSTRACT

Bone sarcomas encompass a group of spontaneous mesenchymal malignancies, among which osteosarcoma, Ewing sarcoma, chondrosarcoma, and chordoma are the most common subtypes. Chondrosarcoma, a relatively prevalent malignant bone tumor that originates from chondrocytes, is characterized by endogenous cartilage ossification within the tumor tissue. Despite the use of aggressive treatment approaches involving extensive surgical resection, chemotherapy, and radiotherapy for patients with osteosarcoma, chondrosarcoma, and chordoma, limited improvements in patient outcomes have been observed. Furthermore, resistance to chemotherapy and radiation therapy has been observed in chondrosarcoma and chordoma cases. Consequently, novel therapeutic approaches for bone sarcomas, including chondrosarcoma, need to be uncovered. Recently, the emergence of immunotherapy and immune checkpoint inhibitors has garnered attention given their clinical success in various diverse types of cancer, thereby prompting investigations into their potential for managing chondrosarcoma. Considering that circumvention of immune surveillance is considered a key factor in the malignant progression of tumors and that immune checkpoints play an important role in modulating antitumor immune effects, blockers or inhibitors targeting these immune checkpoints have become effective therapeutic tools for patients with tumors. One such checkpoint receptor implicated in this process is programmed cell death protein-1 (PD-1). The association between PD-1 and programmed cell death ligand-1 (PD-L1) and cancer progression in humans has been extensively studied, highlighting their remarkable potential as biomarkers for cancer treatment. This review comprehensively examines available studies on current chondrosarcoma treatments and advancements in anti-PD-1/PD-L1 blockade therapy for chondrosarcoma.

Management of liver and gastrointestinal toxicity induced by immune checkpoint inhibitors: Position statement of the AEEH-AEG-SEPD-SEOM-GETECCU

The development of the immune checkpoint inhibitors (ICI) is one of the most remarkable achievements in cancer therapy in recent years. However, their exponential use has led to an increase in immune-related adverse events (irAEs). Gastrointestinal and liver events encompass hepatitis, colitis and upper digestive tract symptoms accounting for the most common irAEs, with incidence rates varying from 2% to 40%, the latter in patients undergoing combined ICIs therapy. Based on the current scientific evidence derived from both randomized clinical trials and real-world studies, this statement document provides recommendations on the diagnosis, treatment and prognosis of the gastrointestinal and hepatic ICI-induced adverse events.

Advancing the Management of Skull Base Chondrosarcomas: A Systematic Review of Targeted Therapies

Background: Chondrosarcomas rank as the second most common primary bone malignancy. Characterized by the production of a cartilaginous matrix, these tumors typically exhibit resistance to both radiotherapy (RT) and chemotherapy (CT), resulting in overall poor outcomes: a high rate of mortality, especially among children and adolescents. Due to the considerable resistance to current conventional therapies such as surgery, CT, and RT, there is an urgent need to identify factors contributing to resistance and discover new strategies for optimal treatment. Over the past decade, researchers have delved into the dysregulation of genes associated with tumor development and therapy resistance to identify potential therapeutic targets for overcoming resistance. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including isocitrate dehydrogenase (IDH1/2) and COL2A1. Molecule-targeting agents and immunotherapies have demonstrated favorable antitumor activity in clinical studies involving patients with advanced chondrosarcomas. In this systematic review, we delineate the clinical features of chondrosarcoma and provide a summary of gene dysregulation and mutation associated with tumor development, as well as targeted therapies as a promising molecular approach. Finally, we analyze the probable role of the tumor microenvironment in chondrosarcoma drug resistance. Methods: A systematic search was conducted across major medical databases (PubMed, Embase, and Cochrane Library) up to 10 November 2023. The search strategy utilized relevant Medical Subject Heading (MeSH) terms and keywords related to “chondrosarcomas”, “target therapies”, “immunotherapies”, and “outcomes”. The studies included in this review consist of randomized controlled trials, non-randomized controlled trials, and cohort studies reporting on the use of target therapies for the treatment of chondrosarcoma in human subjects. Results: Of the initial 279 articles identified, 40 articles were included in the article. The exclusion of 140 articles was due to reasons such as irrelevance, non-reporting of selected results, systematic literature review or meta-analysis, and lack of details on the method/results. Three tables highlighted clinical studies, preclinical studies, and ongoing clinical trials, encompassing 13, 7, and 20 studies, respectively. For the clinical study, a range of molecular targets, such as death receptors 4/5 (DR4 and DR5) (15%), platelet-derived growth factor receptor-alpha or -beta (PDGFR-α, PDGFR-β) (31%), were investigated. Adverse events were mainly constitutional symptoms emphasizing that to improve therapy tolerance, careful observation and tailored management are essential. Preclinical studies analyzed various molecular targets such as DR4/5 (28.6%) and COX-2 (28.6%). The prevalent indicator of antitumoral activity was the apoptotic rate of both a single agent (tumor necrosis factor-related apoptosis-inducing ligand: TRAIL) and double agents (TRAIL-DOX, TRAIL-MG132). Ongoing clinical trials, the majority in Phase II (53.9%), highlighted possible therapeutic strategies such as IDH1 inhibitors and PD-1/PD-L1 inhibitors (30.8%). Conclusions: The present review offers a comprehensive analysis of targeted therapeutics for skull base chondrosarcomas, highlighting a complex landscape characterized by a range of treatment approaches and new opportunities for tailored interventions. The combination of results from molecular research and clinical trials emphasizes the necessity for specialized treatment strategies and the complexity of chondrosarcoma biology.

Management of liver and gastrointestinal toxicity induced by immune checkpoint inhibitors: Position statement of the AEEH-AEG-SEPD-SEOM-GETECCU

The development of the immune checkpoint inhibitors (ICI) is one of the most remarkable achievements in cancer therapy in recent years. However, their exponential use has led to an increase in immune-related adverse events (irAEs). Gastrointestinal and liver events encompass hepatitis, colitis and upper digestive tract symptoms accounting for the most common irAEs, with incidence rates varying from 2 % to 40 %, the latter in patients undergoing combined ICIs therapy. Based on the current scientific evidence derived from both randomized clinical trials and real-world studies, this statement document provides recommendations on the diagnosis, treatment and prognosis of the gastrointestinal and hepatic ICI-induced adverse events.

Role of Immunotherapy in Sarcomas

Sarcomas are a group of malignancies of mesenchymal origin with a plethora of subtypes. Given the sheer heterogeneity of various subtypes and the rarity of the disease, the management of sarcomas has been challenging, with poor patient outcomes. Surgery, radiation therapy and chemotherapy have remained the backbone of treatment in patients with sarcoma. The introduction of immunotherapy has revolutionized the treatment of various solid and hematological malignancies. In this review, we discuss the basics of immunotherapy and the immune microenvironment in sarcomas; various modalities of immunotherapy, like immune checkpoint blockade, oncolytic viruses, cancer-targeted antibodies, vaccine therapy; and adoptive cell therapies like CAR T-cell therapy, T-cell therapy, and TCR therapy.

A Systematic Review of Adjuvant Chemotherapy in Localized Dedifferentiated Chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype of chondrosarcoma with the bimorphic histological appearance of a conventional chondrosarcoma component with abrupt transition to a high-grade, non-cartilaginous sarcoma. DDCS can be radiographically divided into central and peripheral types. Wide resection is currently the main therapeutic option for localized DDCS. Moreover, the effectiveness of adjuvant chemotherapy remains controversial. Therefore, we performed a systematic review of available evidence to evaluate the effect of adjuvant chemotherapy on localized DDCS. The purpose was to compare the 5-year survival rate among patients treated with surgery plus adjuvant chemotherapy or surgery alone for localized DDCS. The search was conducted in PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases. Of the 217 studies shortlisted, 11 retrospective non-randomized studies (comprising 556 patients with localized DDCS) were selected. The 5-year survival rates were similar between the two treatment groups (28.2% (51/181) vs. 24.0% (90/375), respectively). The overall pooled odds ratio was 1.25 (95% confidence interval: 0.80-1.94; p = 0.324), and heterogeneity I2 was 2%. However, when limited to peripheral DDCS, adjuvant chemotherapy was associated with prolonged survival (p = 0.03). Due to the paucity of included studies and the absence of prospective comparative studies, no conclusions can be drawn regarding the effectiveness or ineffectiveness of adjuvant chemotherapy for localized DDCS.

Regorafenib in patients with advanced Ewing sarcoma: results of a non-comparative, randomised, double-blind, placebo-controlled, multicentre Phase II study

BACKGROUND

The REGOBONE multi-cohort study explored the efficacy and safety of regorafenib for patients with advanced bone sarcomas; this report details the Ewing sarcoma (ES) cohort.

METHODS

Patients with relapsed ES progressing despite prior standard therapy, were randomised (2:1) to receive regorafenib or placebo. Patients on placebo could crossover to receive regorafenib after centrally confirmed progression. The primary endpoint was the progression-free rate at 8 weeks. With one-sided α of 0.05, and 80% power, at least 14/24 progression-free patients at 8 weeks were needed for success.

RESULTS

From September 2014 to November 2019, 41 patients were accrued. 36 patients were evaluable for efficacy: 23 on regorafenib and 13 on placebo. Thirteen patients (56%; one-sided 95% CI [37.5%-[)) were progression-free at 8 weeks on regorafenib vs. 1 (7.7%; 95% CI [0.4%-[) on placebo. Median PFS was 11.4 weeks on regorafenib, and 3.9 weeks on placebo. Ten placebo patients crossed over to receive regorafenib after progression. The most common grade ≥3 regorafenib-related adverse events were pain (22%), asthenia (17%), thrombocytopenia (13%) and diarrhoea (13%).

CONCLUSION

Although the primary endpoint was not met statistically in this randomised cohort, there is evidence to suggest that regorafenib might modestly delay tumour progression in relapsed ES after failure of prior chemotherapy.

Immune checkpoint inhibitors in sarcomas: a systematic review

Sarcomas are tumors that originate from mesenchymal cells. The variety of sarcomas' response to chemotherapy and the wide range of prognosis reflect their heterogeneity. In order to improve the rates of response, the research has been orientated toward other forms of therapy, such as targeted therapies and immunotherapy or toward combinations of them. Immune checkpoint inhibitors (ICIs) have been the highlight of immunotherapy in the last decade. Although ICIs are already included in the guidelines of different malignancies, their clinical benefit in sarcomas is still under study. Alveolar soft part sarcomas, undifferentiated pleomorphic sarcomas and other subtypes of sarcoma with high presence of tertiary lymphoid structures tend to respond to ICIs, but further investigation is still needed. Furthermore, the search of predictive biomarkers to determine the type of sarcomas that are sensitive to ICIs is still very challenging. This review will focus on the results of clinical trials, which examine the effect of ICIs and their combination with chemotherapy, targeted therapies and other forms of immunotherapy in sarcomas.

Perianal rhabdomyosarcoma in an adult: A case report and review of the literature

Perianal/perineal rhabdomyosarcomas (PRMS) is rare, and the outcome is poor. A 29-year-old female presented with perineal rhabdomyosarcomas revealed metastases to inguinal lymph nodes on the bilateral side. Disease progression was discovered when the patient got adjuvant epirubicin, ifosfamide, and bevacizumab for 2 cycles. After 3 cycles of nivolumab, dacarbazine, cisplatin, and vinblastine therapy, a partial response was identified in the patient. The surgical resection was performed. The patient received neoadjuvant chemotherapy before surgery and was weak after surgery, so he did not receive chemoradiotherapy. The patient succumbed after 11 months postoperatively due to widespread intraabdominal metastasis.

Advances in treatment of alveolar soft part sarcoma: an updated review

Alveolar soft part sarcoma is a rare neoplasm of uncertain histogenesis that belongs to a newly defined category of ultra-rare sarcomas. The neoplasm is characterized by a specific chromosomal translocation, der (17) t(X; 17)(p11.2;q25), that results in ASPSCR1-TFE3 gene fusion. The natural history of alveolar soft part sarcoma describes indolent behaviour with slow progression in deep soft tissues of the extremities, trunk and head/neck in adolescents and young adults. A high rate of detection of distant metastasis at presentation has been reported, and the most common metastatic sites in decreasing order of frequency are the lung, bone and brain. Complete surgical resection remains the standard treatment strategy, whereas radiotherapy is indicated for patients with inadequate surgical margins or unresectable tumours. Although alveolar soft part sarcoma is refractory to conventional doxorubicin-based chemotherapy, monotherapy or combination therapy using tyrosine kinase inhibitors and immune checkpoint inhibitors have provided antitumor activity and emerged as new treatment strategies. This article provides an overview of the current understanding of this ultra-rare sarcoma and recent advancements in treatments according to the clinical stage of alveolar soft part sarcoma.

Research progress in the mechanism and treatment of osteosarcoma

ABSTRACT

Osteosarcoma (OS) is the most common primary malignant bone tumor that more commonly occurs in children and adolescents. The most commonly used treatment for OS is surgery combined with chemotherapy, but the treatment outcomes are typically unsatisfactory. High rates of metastasis and post-treatment recurrence rates are major challenges in the treatment of OS. This underlines the need for studying the in-depth characterization of the pathogenetic mechanisms of OS and development of more effective therapeutic modalities. Previous studies have demonstrated the important role of the bone microenvironment and the regulation of signaling pathways in the occurrence and development of OS. In this review, we discussed the available evidence pertaining to the mechanisms of OS development and identified therapeutic targets for OS. We also summarized the available treatment modalities for OS and identified future priorities for therapeutics research.

Dedifferentiated Chondrosarcoma: Diagnostic Controversies and Emerging Therapeutic Targets

PURPOSE OF REVIEW

The pathogenesis of dedifferentiated chondrosarcoma is controversial, and no genetic abnormality has consistently been identified in the disease. Focusing on the diagnostic challenges encountered in dedifferentiated chondrosarcoma, the following review aims at summarizing the tumor's active neoplastic pathways while highlighting therapeutic modalities that could potentially be explored to enhance patient survivorship.

RECENT FINDINGS

Owing to the challenging examination of small needle biopsy sampling as well as the disease's overlapping morphological and immunohistochemical features with other bone and soft-tissue sarcomas, the diagnosis of dedifferentiated chondrosarcoma can be problematic. While combined doxorubicin- and cisplatin-based regimens remain the first-line systemic chemotherapy in the disease, ~50% of tumors carry EXT1/2 or IDH1/2 mutations, advancing EXT or IDH inhibitors as potential alternative therapies, respectively. Despite systemic chemotherapy, dedifferentiated chondrosarcoma remains an aggressive tumor with dismal prognosis and limited survival. A multidisciplinary collaboration across multiple cancer centers is warranted to yield an accurate diagnosis, understand the disease's underlying pathogenesis, develop adequate treatment, and improve patient survivorship.

Cancer-Erythrocyte Membrane-Mimicking Fe3O4 Nanoparticles and DHJS for Ferroptosis/Immunotherapy Synergism in Tumors

Ferroptosis is characterized by iron accumulation and lipid peroxidation. However, a clinical dose of Fe3O4 nanoparticles could not cause effective ferroptosis in tumors, and the mechanism is yet to be completely understood. In this study, using RNA-seq data, we found that tumor cells could feedback-activate the antioxidant system by upregulating Nrf-2 expression, thus avoiding ferroptosis caused by Fe3O4 nanoparticles. We also found that DHJS (a probe for ROS generation) can antagonize Nrf-2 expression when it synergizes with Fe3O4 nanoparticles, thus inducing ferroptosis in tumor cells. Considering these findings, we created a biomimetic hybrid cell membrane camouflaged by PLGA-loaded Fe3O4 and DHJS to treat osteosarcoma. The hybrid cell membrane endowed the core nanoparticle with the extension of blood circulation life and enhanced homologous targeting ability. In addition, DHJS and Fe3O4 in nanoparticles prompted synergistically lethal ferroptosis in cancer cells and induced macrophage M1 polarization as well as the infiltration of CD8(+) T cells and dendritic cells in tumors. In summary, this study provides novel mechanistic insights and practical strategies for ferroptosis induction of Fe3O4 nanoparticles. Meanwhile, the synthesized biomimetic nanoparticles exhibited synergistic ferroptosis/immunotherapy against osteosarcoma.

A TLR4 Agonist Induces Osteosarcoma Regression by Inducing an Antitumor Immune Response and Reprogramming M2 Macrophages to M1 Macrophages

Osteosarcoma (OsA) has limited treatment options and stagnant 5-year survival rates. Its immune microenvironment is characterized by a predominance of tumor-associated macrophages (TAMs), whose role in OsA progression remain unclear. Nevertheless, immunotherapies aiming to modulate macrophages activation and polarization could be of interest for OsA treatment. In this study, the antitumor effect of a liposome-encapsulated chemically detoxified lipopolysaccharide (Lipo-MP-LPS) was evaluated as a therapeutic approach for OsA. Lipo-MP-LPS is a toll-like receptor 4 (TLR4) agonist sufficiently safe and soluble to be IV administered at effective doses. Lipo-MP-LPS exhibited a significant antitumor response, with tumor regression in 50% of treated animals and delayed tumor progression in the remaining 50%. The agent inhibited tumor growth by 75%, surpassing the efficacy of other immunotherapies tested in OsA. Lipo-MP-LPS modulated OsA's immune microenvironment by favoring the transition of M2 macrophages to M1 phenotype, creating a proinflammatory milieu and facilitating T-cell recruitment and antitumor immune response. Overall, the study demonstrates the potent antitumor effect of Lipo-MP-LPS as monotherapy in an OsA immunocompetent model. Reprogramming macrophages and altering the immune microenvironment likely contribute to the observed tumor control. These findings support the concept of immunomodulatory approaches for the treatment of highly resistant tumors like OsA.

Mesenchymal Chondrosarcoma from Diagnosis to Clinical Trials

Mesenchymal chondrosarcoma (MCS) is a rare subtype of chondrosarcoma with a poor prognosis. Although these tumors are sensitive to radiotherapy/chemotherapy, the standard treatment for localized MCS is only surgical resection, and there are no established treatment guidelines for patients with advanced and metastatic MCS. Due to the low incidence of MCS, the pathology of these tumors is still unknown, and other therapeutic options are lacking. Some studies show the potential role of the PDGF/PPI3K/AKT, PKC/RAF/MEK/ERK, and pRB pathways, and BCL2 overexpression in the pathogenesis of MCS. These findings provide an opportunity to use protein kinases and BCL2 inhibitors as potential therapy in MCS. In this review, we summarize the current knowledge about MCS diagnosis and treatment options. We show the immunological and molecular biomarkers used in the diagnosis of MCS. In addition, we discuss the known prognostic and predictive factors in MCS. Finally, we present the novel trends, including targeted therapies and ongoing clinical trials using protein kinase inhibitors and the death receptor 5 (DR5) agonist, which may be the focus of future MCS treatment studies.

Results of an Open-label, Phase Ia/b Study of Pembrolizumab plus Olaratumab in Patients with Unresectable, Locally Advanced, or Metastatic Soft-Tissue Sarcoma

PURPOSE

The study evaluated safety and efficacy of olaratumab + pembrolizumab in patients with unresectable locally advanced/metastatic soft-tissue sarcoma (STS) with disease progression on standard treatment.

PATIENTS AND METHODS

This was open-label, multicenter, nonrandomized, phase Ia/Ib dose-escalation study followed by cohort expansion (olaratumab + pembrolizumab intravenous infusion). Primary objectives were safety and tolerability.

RESULTS

The majority of patients enrolled (n = 41) were female [phase Ia: 9 of 13, phase Ib/dose-expansion cohort (DEC), 17 of 28], aged < 65 years. In phases Ia and Ib, 13 and 26 patients received prior systemic therapy, respectively. Patients received olaratumab 15 mg/kg (phase Ia; cohort 1) or 20 mg/kg (phase Ia; cohort 2 and phase Ib) and pembrolizumab 200 mg (phase Ia/Ib). The median (Q1-Q3) duration of therapy (olaratumab) was 6.0 (3.0-11.9; cohort 1), 14.4 (12.4-20.9; cohort 2), and 14.0 (6.0-21.8) weeks (DEC). No dose-limiting toxicities and few grade ≥ 3 treatment-emergent adverse events [TEAE; 15 mg/kg: 2 (increased lipase); 20 mg/kg: 1 (increased lipase), 1 (colitis), 2 (diarrhea), 3 (anemia)] were reported. Two TEAEs (increased lipase) were related to study discontinuations. Twenty-one patients reported mild (grade ≤ 2) TEAEs [phase Ia, disease control rate (DCR):14.3% (1/7, cohort 1); 66.7% (4/6, cohort 2); no responses were reported; phase Ib, DCR: 53.6% (15/28); objective response rate: 21.4% (6/28; RECIST and irRECIST criteria)]. No response was observed in patients with programmed death ligand-1-positive tumors.

CONCLUSIONS

Antitumor activity was observed in some patients in DEC, and combination was well tolerated with manageable safety profile. Further studies are warranted to evaluate the efficacy and mechanistic impact of platelet-derived growth factor receptor inhibitors with immune checkpoint modulator coadministration.

Dedifferentiated Chondrosarcoma from Molecular Pathology to Current Treatment and Clinical Trials

Dedifferentiated chondrosarcoma (DDCS) is a rare subtype of chondrosarcoma, a primary cartilaginous malignant neoplasm. It accounts for up to 1-2% of all chondrosarcomas and is generally associated with one of the poorest prognoses among all chondrosarcomas with the highest risk of metastasis. The 5-year survival rates range from 7% to 24%. DDCS may develop at any age, but the average presentation age is over 50. The most common locations are the femur, pelvis humerus, scapula, rib, and tibia. The standard treatment for localised disease is surgical resection. Most patients are diagnosed in unresectable and advanced stages, and chemotherapy for localised and metastatic dedifferentiated DDCS follows protocols used for osteosarcoma.

TIM-3 Qualifies as a Potential Immunotherapeutic Target in Specific Subsets of Patients with High-Risk Soft Tissue Sarcomas (HR-STS)

(1) Background: The expression of T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), an immune checkpoint receptor on T cells, has been associated with dismal outcomes and advanced tumor stages in various solid tumors. The blockade of TIM-3 is currently under examination in several clinical trials. This study examines TIM-3 expression in high-risk soft tissue sarcomas (HR-STS). (2) Methods: Tumor cell expression of TIM-3 on protein level was analyzed in pre-treatment biopsies of patients with HR-STS. TIM-3 expression was correlated with clinicopathological parameters including tumor-infiltrating lymphocyte (TIL) counts, programmed cell death 1 (PD-1) and programmed cell death ligand 1 (PDL-1) expression in patients with HR-STS. Survival dependent on the expression of TIM-3 was analyzed. (3) Results: TIM-3 expression was observed in 101 (56%) out of 179 pre-treatment biopsies of patients with HR-STS. TIM-3 expression was significantly more often observed in undifferentiated pleomorphic sarcomas (UPS) compared to other histological subtypes (p < 0.001), high TIL counts (p < 0.001), and high PD-1 (p < 0.001) and PD-L1 expression (p < 0.001). TIM-3 expression did not have a prognostic impact on survival in patients with HR-STS. (4) Conclusions: This is the first study to demonstrate a significant tumor cell expression of TIM-3 in specific subsets of patients with HR-STS. TIM-3 qualifies as a potential immunotherapeutic target in HR-STS.

Pharmacotherapeutic strategies for epithelioid sarcoma: are we any closer to a non-surgical cure?

INTRODUCTION

Epithelioid sarcoma (ES) is a rare soft tissue sarcoma subtype, predominantly occurring in children and young adults. Despite optimal management of localized disease, approximately 50% of patients develop advanced disease. The management of advanced ES remains challenging due to limited response to conventional chemotherapy and despite novel oral EZH2 inhibitors that have better tolerability but similar efficacy to chemotherapy.

AREAS COVERED

We performed a literature review using the PubMed (MEDLINE) and Web of Science databases. We have focused on the role of chemotherapy, targeted agents such as EZH2 inhibitors, potential new targets and immune checkpoint inhibitors and combinations of therapies currently undergoing clinical investigation.

EXPERT OPINION

ES is a soft tissue sarcoma with a heterogeneous pathological, clinical, and molecular presentation. In the current era of precision medicine, more trials with targeted therapies and a combination of chemotherapy or immunotherapy with targeted therapies are required to establish optimal treatment for ES.

Molecular In-Depth Characterization of Chondrosarcoma for Current and Future Targeted Therapies

Chondrosarcoma (CHS) are heterogenous, but as a whole, represent the second most common primary malignant bone tumor entity. Although knowledge on tumor biology has grown exponentially during the past few decades, surgical resection remains the gold standard for the treatment of these tumors, while radiation and differentiated chemotherapy do not result in sufficient cancer control. An in-depth molecular characterization of CHS reveals significant differences compared to tumors of epithelial origin. Genetically, CHS are heterogenous, but there is no characteristic mutation defining CHS, and yet, IDH1 and IDH2 mutations are frequent. Hypovascularization, extracellular matrix composition of collagen, proteoglycans, and hyaluronan create a mechanical barrier for tumor suppressive immune cells. Comparatively low proliferation rates, MDR-1 expression and an acidic tumor microenvironment further limit therapeutic options in CHS. Future advances in CHS therapy depend on the further characterization of CHS, especially the tumor immune microenvironment, for improved and better targeted therapies.

Current Landscape of Immunotherapy for Advanced Sarcoma

There is substantial heterogeneity between different subtypes of sarcoma regarding their biological behavior and microenvironment, which impacts their responsiveness to immunotherapy. Alveolar soft-part sarcoma, synovial sarcoma and undifferentiated pleomorphic sarcoma show higher immunogenicity and better responses to checkpoint inhibitors. Combination strategies adding immunotherapy to chemotherapy and/or tyrosine-kinase inhibitors globally seem superior to single-agent schemes. Therapeutic vaccines and different forms of adoptive cell therapy, mainly engineered TCRs, CAR-T cells and TIL therapy, are emerging as new forms of immunotherapy for advanced solid tumors. Tumor lymphocytic infiltration and other prognostic and predictive biomarkers are under research.

The Landscape of Immunotherapy for Retroperitoneal Sarcoma

Significant multidisciplinary scientific effort has been undertaken to understand the heterogeneous family of neoplasms that comprise soft tissue sarcomas. Within this family of neoplasms, outcomes for retroperitoneal sarcomas (RPS) are currently limited given a lack of effective therapies. In this review, we focus on immunotherapy and its relationship with the common RPS histologic subtypes. Although initial outcomes for RPS patients with immune checkpoint inhibition alone have been somewhat disappointing, subsequent analyses on histologies, the tumor microenvironment, sarcoma immune class, tumor infiltrating lymphocytes and genetic analysis for tumor mutational burden have yielded insight into the interplay between sarcomas and immunotherapy. Such approaches have all provided critical insight into the environment and characterization of these tumors, with targets for potential immunotherapy in future clinical trials. With this insight, molecularly tailored combination treatments for improving response rates and oncologic outcomes for RPS are promising.

Intratumoral STING activation causes durable immunogenic tumor eradication in the KP soft tissue sarcoma model

Introduction

Soft tissue sarcomas (STS) are highly metastatic, connective-tissue lineage solid cancers. Immunologically, sarcomas are frequently characterized by a paucity of tumor infiltrating lymphocytes and an immune suppressive microenvironment. Activation of the STING pathway can induce potent immune-driven anti-tumor responses within immunogenic solid tumors; however, this strategy has not been evaluated in immunologically cold sarcomas. Herein, we assessed the therapeutic response of intratumoral STING activation in an immunologically cold murine model of undifferentiated pleomorphic sarcoma (UPS).

Materials and Results

A single intratumoral injection of the murine STING agonist, DMXAA resulted in durable cure in up to 60% of UPS-bearing mice. In mice with synchronous lung metastases, STING activation within hindlimb tumors resulted in 50% cure in both anatomic sites. Surviving mice all rejected UPS re-challenge in the hindlimb and lung. Therapeutic efficacy of STING was inhibited by lymphocyte deficiency but unaffected by macrophage deficiency. Immune phenotyping demonstrated enrichment of lymphocytic responses in tumors at multiple timepoints following treatment. Immune checkpoint blockade enhanced survival following STING activation.

Discussion

These data suggest intratumoral activation of the STING pathway elicits local and systemic anti-tumor immune responses in a lymphocyte poor sarcoma model and deserves further evaluation as an adjunctive local and systemic treatment for sarcomas.

Exploring the landscape of immunotherapy approaches in sarcomas

Sarcomas comprise a heterogenous group of malignancies, of more than 100 different entities, arising from mesenchymal tissue, and accounting for 1% of adult malignancies. Surgery, radiotherapy and systemic therapy constitute the therapeutic armamentarium against sarcomas, with surgical excision and conventional chemotherapy, remaining the mainstay of treatment for local and advanced disease, respectively. The prognosis for patients with metastatic disease is dismal and novel therapeutic approaches are urgently required to improve survival outcomes. Immunotherapy, is a rapidly evolving field in oncology, which has been successfully applied in multiple cancers to date. Immunomodulating antibodies, adoptive cellular therapy, cancer vaccines, and cytokines have been tested in patients with different types of sarcomas through clinical trials, pilot studies, retrospective and prospective studies. The results of these studies regarding the efficacy of different types of immunotherapies in sarcomas are conflicting, and the application of immunotherapy in daily clinical practice remains limited. Additional clinical studies are ongoing in an effort to delineate the role of immunotherapy in patients with specific sarcoma subtypes.

Case report: Treatment of metastatic dedifferentiated chondrosarcoma with pembrolizumab yields sustained complete response

Dedifferentiated chondrosarcomas (DDCS) are aggressive tumors with poor outcomes. Treatment of localized DDCS is primarily surgical, though most patients present with unresectable or metastatic disease. Systemic treatment options for advanced DDCS are limited, and the benefits of chemotherapy in this patient population remain controversial. Among other systemic therapy options, there is emerging clinical evidence to support the use of immunotherapy in patients with advanced DDCS. However, studies regarding the efficacy of immunotherapy in advanced DDCS are limited. Here, we present the case of a patient with metastatic, programmed death-ligand 1 (PD-L1)-positive DDCS treated with pembrolizumab who showed a sustained complete response for 24 months after initiation of therapy. To our knowledge, this case represents one of few documented cases of metastatic chondrosarcoma with sustained response to immunotherapy. The impressive response seen with PD-L1 inhibition in our patient indicates that immunotherapy is a successful treatment option in a subset of DDCS patients, and further investigation is needed to identify potential responders to immunotherapy.

Receptor Tyrosine Kinase Inhibitors for the Treatment of Recurrent and Unresectable Bone Sarcomas

Bone sarcomas are a heterogeneous group of rare tumors with a predominance in the young population. Few options of systemic treatment are available once they become unresectable and resistant to conventional chemotherapy. A better knowledge of the key role that tyrosine kinase receptors (VEGFR, RET, MET, AXL, PDGFR, KIT, FGFR, IGF-1R) may play in the pathogenesis of these tumors has led to the development of multi-target inhibitors (TKIs) that are progressively being incorporated into our therapeutic arsenal. Osteosarcoma (OS) is the most frequent primary bone tumor and several TKIs have demonstrated clinical benefit in phase II clinical trials (cabozantinib, regorafenib, apatinib, sorafenib, and lenvatinib). Although the development of TKIs for other primary bone tumors is less advanced, preclinical data and early trials have begun to show their potential benefit in advanced Ewing sarcoma (ES) and rarer bone tumors (chondrosarcoma, chordoma, giant cell tumor of bone, and undifferentiated pleomorphic sarcoma). Previous reviews have mainly provided information on TKIs for OS and ES. We aim to summarize the existing knowledge regarding the use of TKIs in all bone sarcomas including the most recent studies as well as the potential synergistic effects of their combination with other systemic therapies.

Comparative Combinatorial Implications and Theranostics of Immunotherapy in the Impediment of Alveolar Soft Part Sarcoma

BACKGROUND

Immune checkpoint inhibitors (ICIs), specifically programmed cell death receptor- 1/ligand 1 (PD-1/L1) inhibitors, have shown potential pharmacological efficacy in several cancers. Nonetheless, data pertinent to their therapeutic efficacy in alveolar soft-part sarcoma (ASPS) are limited.

OBJECTIVE

The retrospective aspects of ICIs (anti-PD1/PD-L1 blockers) to target ASPS are comparatively analyzed for clinical outcomes with other targeted immunotherapy modalities.

METHODS

We have conducted a systematic review without statistical analysis or comprehensive meta-analysis by collecting the articles published between 1952 and Sep 10th, 2020, by searching the following words: alveolar soft part sarcoma and immunotherapy including immune checkpoint, immune checkpoint inhibitors, and PD-1, PD-L1. We performed a pooled analysis of case reports, conferences, clinical trials, and other research reports pertinent to the efficacy of a PD-1 or PD-L1 antagonist in patients diagnosed with metastatic ASPS.

RESULTS

The effective studies include 10 case reports, 2 conference reports, 5 clinical trials, and 2 additional research reports. A total of 110 patients were reported to be enrolled in the pooled analysis; among them, 87 (78.38%) received a PD-1/PD-L1 antagonist. For patients who received anti-PD-1/PD-L1as monotherapy, their clinical response rates (CRR) were 63.22% whereas those who received targeted therapy and immunotherapy had a CRR of 78.95% (15/19). In the patients treated with double immunotherapy, their CRR was 100% (4/4). Tumor mutational burden and mismatch repair status have significant implications for predicting the ASPS prognosis.

CONCLUSION

Alveolar soft-part sarcoma patients with distant metastases can exhibit better clinical outcomes with immunotherapy, particularly toripalimab, atezolizumab, and axitinib combinatorial regimen with pembrolizumab. In addition, this review describes the therapeutic implications to guide personalized medicine depending on the expression patterns of PD-1/PD-L1 during the immunotherapy with ASPS.

Evaluation of Short-Term Efficacy of PD-1 Monoclonal Antibody Immunotherapy for Lymphoma by Positron Emission Tomography/Computed Tomography Imaging with Convolutional Neural Network Image Registration Algorithm

The objective of this study was to investigate the value of PET/CT imaging based on CNN image registration algorithm in evaluating the short-term efficacy of PD-1 monoclonal antibody immunotherapy for lymphoma. 36 patients with advanced lymphoma confirmed by histology or cytochemistry and treated with PD-1 monoclonal antibody admitted to hospital were included. In addition, 38 normal controls were from healthy volunteers. All patients were treated with PD-1 monoclonal antibody intravenous infusion, and the image data were processed by CT with intelligent segmentation algorithm. Medication method: nivolumab 3 mg/kg for 2 weeks; pembrolizumab 2 mg/kg for 3 weeks; and continuous medication until tumor progression or unacceptable adverse reactions. Efficacy was evaluated every 3 cycles. Imaging examinations were performed after 3 weeks of medication to evaluate the therapeutic effect. The concentrations of IL-2, IL-7, basic fibroblast growth factor (FGF), granulocyte-macrophage colony-stimulating factor (GM-CSF), platelet-derived growth factor (PDGF-bb), and other factors in the normal control group were significantly higher than those in the advanced lymphoma patients, and the differences were statistically significant (P < 0.05). The PET/CT imaging automatic segmentation accuracy of the CNN image registration algorithm was greater than 81%, and 27 patients were treated for more than 3 cycles, including 1 case of partial remission (PR) (3.7%), 16 cases of stable disease (SD) (59.3%) after 3 cycles of treatment, and 10 cases of progressive disease (PD) (37%). After 6 cycles of treatment, 1 case was PR (8.3%), 7 cases were SD (58.4%), and 4 cases were PD (33.3%). Adverse reactions included fever, fatigue, gastrointestinal reactions, hypothyroidism, and interstitial pneumonia. PD-1 monoclonal antibody immunotherapy had a certain short-term effect on lymphoma.

Combination of 5-Fluorouracil with Photodynamic Therapy: Enhancement of Innate and Adaptive Immune Responses in a Murine Model of Actinic Keratosis

We previously showed that a combination of differentiation-inducing agents (5-fluorouracil, vitamin D3, or methotrexate) and aminolevulinate-based photodynamic therapy (PDT) improves clinical responses by enhancing protoporphyrin IX (PpIX) photosensitizer levels and cell death. Here, we show that in addition to its previously known effects, 5-fluorouracil (5FU) enhances PDT-induced tumor-regressing immunity. Murine actinic keratoses (AK) were treated with topical 5FU or vehicle for three days prior to ALA application, followed by blue light illumination (~417 nm). Lesions were harvested for time-course analyses of innate immune cell recruitment into lesions, i.e., neutrophils (Ly6G+) and macrophages (F4/80+), which peaked at 72 hours and 1 week post PDT, respectively, and was greater in 5FU treated lesions. Enhanced infiltration of activated T cells (CD3+) throughout the time course, and of cytotoxic T cells (CD8+) at 1 - 2 weeks post PDT, also occurred in 5FU treated lesions. 5FU pretreatment reduced the presence of cells expressing the immune checkpoint marker PD-1 at ~72 hours post PDT, favoring cytotoxic T cell activity. A combination of 5FU and PDT, each individually known to induce long-term tumor-targeting immune responses in addition to their more immediate effects on cancer cells, may synergize to provide better management of squamous precancers.

Immune checkpoints in osteosarcoma: Recent advances and therapeutic potential

Osteosarcoma is the most common primary malignant bone tumor and is associated with a high risk of recurrence and distant metastasis. Effective treatment for osteosarcoma, especially advanced osteosarcoma, has stagnated over the past four decades. The advent of immune checkpoint inhibitor (ICI) has transformed the treatment paradigm for multiple malignant tumor types and indicated a potential therapeutic strategy for osteosarcoma. In this review, we discuss recent advances in immune checkpoints, including programmed cell death protein-1 (PD-1), programmed cell death protein ligand-1 (PD-L1), and cytotoxic T lymphocyte-associated antigen-4 (CTLA-4), and their related ICIs for osteosarcoma treatment. We present the main existing mechanisms of resistance to ICIs therapy in osteosarcoma. Moreover, we summarize the current strategies for improving the efficacy of ICIs in osteosarcoma and address the potential predictive biomarkers of ICIs treatment in osteosarcoma.

Clinical genomic profiling in the management of patients with soft tissue and bone sarcoma

There are more than 70 distinct sarcomas, and this diversity complicates the development of precision-based therapeutics for these cancers. Prospective comprehensive genomic profiling could overcome this challenge by providing insight into sarcomas' molecular drivers. Through targeted panel sequencing of 7494 sarcomas representing 44 histologies, we identify highly recurrent and type-specific alterations that aid in diagnosis and treatment decisions. Sequencing could lead to refinement or reassignment of 10.5% of diagnoses. Nearly one-third of patients (31.7%) harbor potentially actionable alterations, including a significant proportion (2.6%) with kinase gene rearrangements; 3.9% have a tumor mutational burden ≥10 mut/Mb. We describe low frequencies of microsatellite instability (<0.3%) and a high degree of genome-wide loss of heterozygosity (15%) across sarcomas, which are not readily explained by homologous recombination deficiency (observed in 2.5% of cases). In a clinically annotated subset of 118 patients, we validate actionable genetic events as therapeutic targets. Collectively, our findings reveal the genetic landscape of human sarcomas, which may inform future development of therapeutics and improve clinical outcomes for patients with these rare cancers.

Case Report: A PD-L1-Positive Patient With Pleomorphic Rhabdomyosarcoma Achieving an Impressive Response to Immunotherapy

There is currently a lack of effective systemic treatment for patients with advanced pleomorphic rhabdomyosarcoma (PRMS). Although programmed death protein 1 (PD-1) inhibitors have shown efficacy in various solid tumors, their effects on PRMS have not been well established. Here, we present a case of a 12-year-old Chinese male adolescent with metastatic PRMS who benefited from the PD-1 inhibitor nivolumab. The patient initially underwent primary tumor resection but failed to respond to subsequent first-line chemotherapy and second-line pazopanib treatment. Pathological examination showed positive PD-L1 expression and tumor-infiltrating lymphocytes in the tumor tissue, and the patient was administered nivolumab as a posterior-line treatment. After attaining a clinically partial response (PR), surgical resection was performed, which was followed by adjuvant nivolumab. At the time of the submission of this manuscript, the patient achieved recurrence-free survival (RFS) lasting 45 months and counting. This is the first clinical evidence that a patient with refractory PRMS was controlled by anti-PD-1 antibody, with an RFS lasting more than 3 years. This case suggests that PD-L1 expression and T-cell infiltration could be used as potential biomarkers for PRMS immunotherapy.

Treatment with sorafenib plus camrelizumab after splenectomy for primary splenic angiosarcoma with liver metastasis: A case report and literature review

BACKGROUND

Primary splenic angiosarcoma (PSA) is an extremely rare and aggressive mesenchymal malignancy with high metastatic potential and a poor prognosis. There are no established treatment guidelines for PSA, even for adjuvant therapy. This rare case may provide a reliable therapeutic regime for a better prognosis.

CASE SUMMARY

A 49-year-old female who complained of right-upper quadrant abdominal pain was diagnosed as having PSA with splenic rupture and liver metastasis. After splenectomy and liver tumor resection, she received sorafenib and camrelizumab therapy. After 15 mo of follow-up, she is in good condition, without recurrence or any identified metastasis.

CONCLUSION

Immunotherapy combined with targeted therapy could be a potential option for the adjuvant therapy of PSA.

A novel immune-related gene signature predicting survival in sarcoma patients

Sarcomas are a heterogeneous group of rare mesenchymal tumors. The migration of immune cells into these tumors and the prognostic impact of tumor-specific factors determining their interaction with these tumors remain poorly understood. The current risk stratification system is insufficient to provide a precise survival prediction and treatment response. Thus, valid prognostic models are needed to guide treatment. This study analyzed the gene expression and outcome of 980 sarcoma patients from seven public datasets. The abundance of immune cells and the response to immunotherapy was calculated. Immune-related genes (IRGs) were screened through a weighted gene co-expression network analysis (WGCNA). A least absolute shrinkage and selection operator (LASSO) Cox regression was used to establish a powerful IRG signature predicting prognosis. The identified IRG signature incorporated 14 genes and identified high-risk patients in sarcoma cohorts. The 14-IRG signature was identified as an independent risk factor for overall and disease-free survival. Moreover, the IRG signature acted as a potential indicator for immunotherapy. The nomogram based on the risk score was built to provide a more accurate survival prediction. The decision tree with IRG risk score discriminated risk subgroups powerfully. This proposed IRG signature is a robust biomarker to predict outcomes and treatment responses in sarcoma patients.

Immunotherapy for SMARCB1-Deficient Sarcomas: Current Evidence and Future Developments

Mutations in subunits of the SWItch Sucrose Non-Fermentable (SWI/SNF) complex occur in 20% of all human tumors. Among these, the core subunit SMARCB1 is the most frequently mutated, and SMARCB1 loss represents a founder driver event in several malignancies, such as malignant rhabdoid tumors (MRT), epithelioid sarcoma, poorly differentiated chordoma, and renal medullary carcinoma (RMC). Intriguingly, SMARCB1-deficient pediatric MRT and RMC have recently been reported to be immunogenic, despite their very simple genome and low tumor mutational burden. Responses to immune checkpoint inhibitors have further been reported in some SMARCB1-deficient diseases. Here, we will review the preclinical data and clinical data that suggest that immunotherapy, including immune checkpoint inhibitors, may represent a promising therapeutic strategy for SMARCB1-defective tumors. We notably discuss the heterogeneity that exists among the spectrum of malignancies driven by SMARCB1-loss, and highlight challenges that are at stake for developing a personalized immunotherapy for these tumors, notably using molecular profiling of the tumor and of its microenvironment.

Case Report: Complete Response to Antiangiogenesis and Immune Checkpoint Blockade in an Unresectable MMR-Deficient Leiomyosarcoma Harboring Biallelic Loss of PTEN

Background

Leiomyosarcoma (LMS) is a malignant smooth muscle neoplasm, in which the efficacy of immune checkpoint blockade (ICB) is very limited. What is worse, loss of PTEN, known as a negative factor for ICB, frequently occurred in LMS. Seeking new strategies for LMS patients harboring loss of PTEN is important and challenging.

Case Presentation

A 42-year-old Chinese male was diagnosed as having unresectable LMS of the iliopsoas. After the failure of two prior chemotherapy regimens, whole-exome sequencing revealed that tumor tissue had high tumor mutation burden (689 Muts), high microsatellite instability, and some somatic mutations, including PTEN (copy number loss and p.N323fs), MSH6 (p.F1088fs), TP53 p.R273C, ASXL1 p.G645fs, ATR p.S1843P, and CDKN2A p.A118P. Then, antiangiogenic agent (pazopanib or anlotinib) plus pembrolizumab was administered from January 2 to August 6, 2018. However, pazopanib was stopped on June 18 due to the grade 2/3 adverse effect of hand–foot skin reaction, and anlotinib was administered. Considering that the tumor shrunk after immunotherapy, he underwent radical resection on September 6, 2018. The final pathological diagnosis confirmed pathologic complete response (CR). Until the latest follow-up (September 15, 2021), no progressive disease was observed and total disease-free survival has exceeded 36 months.

Conclusion

We presented a patient with an unresectable mismatch repair (MMR)-deficient LMS harboring biallelic loss of PTEN who achieved CR from a combination strategy of antiangiogenesis plus pembrolizumab. Such a strategy might be a promising strategy to overcome the ICB resistance caused by the loss of PTEN. Such conclusions need to be further confirmed in further investigations.

Prognostic significance and therapeutic potentials of immune checkpoints in osteosarcoma

Although there exist manifold strategies for cancer treatment, researchers are obliged to develop novel treatments based on the challenges that arise. One of these recent treatment approaches is cancer immunotherapy, which enjoys various types of strategies itself. However, one of the most significant methods, in this regard, is employing immune checkpoint proteins (ICPs). Bone sarcomas have several subtypes, with the most common ones being chordoma, chondrosarcoma, Ewing sarcoma, and osteosarcoma. Although many aggressive treatment approaches, including radiotherapy, chemotherapy, and surgical resection, have been employed over the last decades, significantly improved outcomes have not been observed for Ewing sarcoma or osteosarcoma patients. Additionally, chordoma and chdrosarcoma resist against both radiation and chemotherapy. Accordingly, elucidating how recent therapies could affect bone sarcomas is necessary. Checkpoint inhibitors have attracted great attention for the treatment of several cancer types, including bone sarcoma. Herein, the recent advances of current immune checkpoint targets, such as anti-PD-1/PD-L1 and anti-CTLA-4 blockade, for the treatment of bone sarcoma have been reviewed.

Current approaches to management of bone sarcoma in adolescent and young adult patients

Bone tumors are a group of histologically diverse diseases that occur across all ages. Two of the commonest, osteosarcoma (OS) and Ewing sarcoma (ES), are regarded as characteristic adolescent and young adult (AYA) cancers with an incidence peak in AYAs. They are curable for some but associated with unacceptably high rates of treatment failure and morbidity. The introduction of effective new therapeutics for bone sarcomas is slow, and to date, complex biology has been insufficiently characterized to allow more rapid therapeutic exploitation. This review focuses on current standards of care, recent advances that have or may soon change that standard of care and challenges to the expert clinical research community that we suggest must be met.

Therapeutic Targets and Emerging Treatments in Advanced Chondrosarcoma

Due to resistance to standard anticancer agents, it is difficult to control the disease progression in patients with metastatic or unresectable chondrosarcoma. Novel therapeutic approaches, such as molecule-targeting drugs and immunotherapy, are required to improve clinical outcomes in patients with advanced chondrosarcoma. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including IDH1/2 and COL2A1. Several molecule-targeting agents and immunotherapies have shown favorable antitumor activity in clinical studies in patients with advanced chondrosarcomas. This review summarizes recent basic studies on biomarkers and molecular targets and recent clinical studies on the treatment of chondrosarcomas.

MerTK-mediated efferocytosis promotes immune tolerance and tumor progression in osteosarcoma through enhancing M2 polarization and PD-L1 expression

The poor progress of immunotherapy on osteosarcoma patients requires deeper delineation of immune tolerance mechanisms in the osteosarcoma microenvironment and a new therapeutic strategy. Clearance of apoptotic cells by phagocytes, a process termed “efferocytosis,” is ubiquitous in tumors and mediates the suppression of innate immune inflammatory response. Considering the massive infiltrated macrophages in osteosarcoma, efferocytosis probably serves as a potential target, but is rarely studied in osteosarcoma. Here, we verified M2 polarization and PD-L1 expression of macrophages following efferocytosis. Pharmacological inhibition and genetic knockdown were used to explore the underlying pathway. Moreover, tumor progression and immune landscape were evaluated following inhibition of efferocytosis in osteosarcoma model. Our study indicated that efferocytosis promoted PD-L1 expression and M2 polarization of macrophages. Ëfferocytosis was mediated by MerTK receptor in osteosarcoma and regulated the phenotypes of macrophages through the p38/STAT3 pathway. By establishing the murine osteosarcoma model, we emphasized that inhibition of MerTK suppressed tumor growth and enhanced the T cell cytotoxic function by increasing the infiltration of CD8⁺ T cells and decreasing their exhaustion. Our findings demonstrate that MerTK-mediated efferocytosis promotes osteosarcoma progression by enhancing M2 polarization of macrophages and PD-L1-induced immune tolerance, which were regulated through the p38/STAT3 pathway.

Proximal-type epithelioid sarcoma in pubic region expressing L-type amino acid transporter 1: A case report

Proximal-type epithelioid sarcoma is an aggressive malignant soft-tissue neoplasm, a “proximal” variant of epithelioid sarcoma, resistant to multimodal therapy and involved in early tumor-related death. Pertinent treatments are, therefore, continually being explored. A 24-year-old woman with nonmetastatic proximal-type epithelioid sarcoma, originating subcutaneously on the right side of the vulva, underwent surgical resection; the lesion recurred, however, leading to death 3 months after the second surgery. Here described is a case of proximal-type epithelioid sarcoma expressing L-type amino acid transporter 1 (LAT1) that transports essential amino acids and p-borono-L-phenylalanine (BPA)—the chemical compound used in boron neutron capture therapy (BNCT)—and is highly expressed in many malignant tumors. Recently, LAT1 has drawn attention, and relevant treatments have been studied—LAT1 inhibitor and BNCT. LAT1 expression in proximal-type epithelioid sarcoma may lead to cogent treatments for the disease.

[Medicinal treatment of retroperitoneal soft tissue sarcomas]

Retroperitoneal soft tissue sarcomas represent extreme challenges for interdisciplinary treatment teams. The sarcoma-specific experience of surgeons has the greatest impact on the survival of patients; however, too many patients still die despite optimal local treatment. The role of chemotherapy is undisputed only for patients with highly malignant bone sarcomas or rhabdomyosarcomas. For soft tissue sarcomas in adult patients, especially liposarcomas and leiomyosarcomas, the evidence situation is very unsatisfactory. This overview article discusses the complex data situation and controversial aspects that are relevant for current treatment decisions in interdisciplinary treatment teams.

Enhancing the Potential of Immunotherapy in Paediatric Sarcomas: Breaking the Immunosuppressive Barrier with Receptor Tyrosine Kinase Inhibitors

Despite aggressive surgery, chemotherapy, and radiotherapy, survival of children and adolescents and young adults (AYAs) with sarcoma has not improved significantly in the past four decades. Immune checkpoint inhibitors (ICIs) are an exciting type of immunotherapy that offer new opportunities for the treatment of paediatric and AYA sarcomas. However, to date, most children do not derive a benefit from this type of treatment as a monotherapy. The immunosuppressive tumour microenvironment is a major barrier limiting their efficacy. Combinations of ICIs, such as anti-PD-1 therapy, with targeted molecular therapies that have immunomodulatory properties may be the key to breaking through immunosuppressive barriers and improving patient outcomes. Preclinical studies have indicated that several receptor tyrosine kinase inhibitors (RTKi) can alter the tumour microenvironment and boost the efficacy of anti-PD-1 therapy. A number of these combinations have entered phase-1/2 clinical trials, mostly in adults, and in most instances have shown efficacy with manageable side-effects. In this review, we discuss the status of ICI therapy in paediatric and AYA sarcomas and the rationale for co-treatment with RTKis. We highlight new opportunities for the integration of ICI therapy with RTK inhibitors, to improve outcomes for children with sarcoma.

Dedifferentiated chondrosarcoma: current standards of care

Dedifferentiated chondrosarcomas are aggressive variants of chondrosarcoma, associated with poor outcomes. Tumor biphasism is the norm. The majority of these tumors are symptomatic at presentation. Radiologically, large soft tissue masses with bony destruction predominate. Treatment protocols of these tumors are not well defined. Surgical resection forms the standard of care for localized disease. (Neo)adjuvant therapies remain controversial as the results from multiple (mainly retrospective) studies remain conflicting. Age at presentation, stage and ability to obtain negative resection margins are important prognostic factors. The overall prognosis is dismal. Newer and novel therapies targeting the complex genetic makeup of these tumors have renewed interest in the adjuvant setting that could hold promise in the near future.

Case Report: Pulmonary Metastases From Epithelioid Sarcoma in Extremity Favourably Responding to Immunotherapy With Camrelizumab

Epithelioid sarcoma (ES) is a rare soft tissue sarcoma (STS), with limited therapies available for metastatic disease. Here, we describe a case of a 30-year-old male with ES of the left knee and underwent surgery and radiation therapy for the primary disease. After 2 years, he had local recurrence and underwent extensive resection surgery; however, adjuvant chemotherapies were delayed due to recurrent wound infection. Nine months after the second surgery, progressive disease was confirmed after detection of metastases to the lungs and inguinal lymph nodes. Amputation was performed for the local recurrence, followed by inguinal lymph nodes dissection. Pazopanib was transiently administered but discontinued as a result of wound dehiscence. The tumour specimens were detected with unexpected high level of PD-L1 expression and tumoural infiltrating lymphocytes. Subsequently, he received camrelizumab 2.0 mg/kg every 21 days for 18 cycles with rapid remission of the pulmonary metastases. This promising response to camrelizumab indicates that immunotherapies may be an alternative choice for patients with metastatic ES in lung based on analysing the tumour immune microenvironment.