Clinical and Molecular Spectrum of Liposarcoma

New targeted therapies in liposarcoma: state of art and future perspectives

PURPOSE OF REVIEW

Liposarcomas (LPSs) represent the most common soft tissue sarcoma (STS) subtype, and exhibit distinct clinical molecular features according to histological subgroup. Chemotherapy (ChT), and in particular anthracycline-based schedules, still remains the standard of treatment for all LPS forms. However, given the increasing knowledge gained throughout last years about LPS molecular biology and their genomic profiling, new therapeutic alternatives with targeted drugs are now to be considered. In this review, we will highlight most promising ongoing and published clinical trials regarding targeted therapies in LPSs and provide some insights about future approaches and possible new treatment options for this rare disease.

RECENT FINDINGS

Among all the explored targets, mouse double minute 2 homolog amplification and CKD4-Rb axis inhibition seem to be the most promising target in well differentiated/dedifferentiated LPS subtype. On the other hand, myxoid LPS is known to have a particular sensitivity for trabectedin, which acts like a targeted drug due to its specific action on cellular DNA. In addition to these, multiple other strategies are now being evaluated in LPSs, including the administration of immune-checkpoint inhibitors (ICIs) and 'new-old' cytotoxic agents, such as cabazitaxel, in a continuously growing scenario.

SUMMARY

Although preliminary, results of recently published and ongoing examined clinical trials will hopefully be translated in clinical practice in the next future, leading the way to future research in this rare disease.

Pleomorphic Liposarcoma Unraveled: Investigating Histopathological and Immunohistochemical Markers for Tailored Diagnosis and Therapeutic Innovations

Liposarcomas are some of the most challenging soft tissue tumors and are subclassified into multiple subtypes with special histologic and molecular features. The peculiarities of each histopathological subtype influence the clinical behavior, management, and treatment of these neoplasms. For instance, well-differentiated liposarcomas are common soft tissue malignancies and usually display a favorable outcome. On the other hand, pleomorphic liposarcoma is the rarest, yet the most aggressive subtype of liposarcoma. This histopathological diagnosis may be challenging due to the scarce available data and because pleomorphic liposarcomas can mimic other pleomorphic sarcomas or other neoplasms of dissimilar differentiation. Nevertheless, the correct diagnosis of pleomorphic liposarcoma is of utmost importance as such patients are prone to develop local recurrences and metastases. Treatment usually consists of surgical excision along with radiotherapy and follow-up of the patients. Therefore, this review aims to assess the complex clinical, histological, and immunohistochemical features of liposarcomas in order to establish how these characteristics influence the management and prognosis of the patients, emphasizing the particularities of pleomorphic liposarcoma.

An overview on liposarcoma subtypes: Genetic alterations and recent advances in therapeutic strategies

Liposarcoma (LPS) is a rare malignancy of adipocytic differentiation. According to World Health Organization classification, LPS comprises of four principle subtypes Atypical lipomatous tumor/Well-differentiated liposarcoma (ATL/WDLPS), Dedifferentiated liposarcoma (WDLPS), Myxoid liposarcoma (MLPS), and Pleomorphic liposarcoma (PLPS). Each subtype can develop at any location and shows distinct clinical behavior and treatment sensitivity. ATL/ WDLPS subtype has a higher incidence rate, low recurrence, and is insensitive to radiation and chemotherapy. DDLPS is the focal progression of WDLPS, which is aggressive and highly metastasizing. MLPS is sensitive to radiation and chemotherapy, with a higher recurrence rate and metastasis. PLPS subtype is highly metastasizing, has a poor prognosis, and exhibiting higher recurrence rate. Initial histological analysis provides information for the characterization of LPS subtypes', further molecular and genetic analysis provides certain subtype specifications, such as gene amplifications and gene fusions. Such molecular genetic alterations will be useful as therapeutic targets in various cancers, including the LPS subtypes. A wide range of novel therapeutic agents based on genetic alterations that aim to target LPS subtypes specifically are under investigation. This review summarizes the LPS subtype classification, their molecular genetic characteristics, and the implications of genetic alterations in therapeutics.

Clinical, Diagnostic, and Treatment Characteristics of Orbital Liposarcoma

PURPOSE

To clarify the clinical, diagnostic, and treatment characteristics of orbital liposarcoma.

DESIGN

Retrospective observational case series.

METHODS

A review was performed of electronic medical records, histopathology, radiological images, and follow-up information for 21 patients with orbital liposarcoma.

RESULTS

The predominant clinical manifestation of this disease was painless exophthalmos. The most frequently encountered pathological types were well-differentiated and myxoid liposarcoma. Preoperative radiological images from 15 patients showed that orbital liposarcoma initially developed in extraocular muscle in 9 patients. Furthermore, all well-differentiated liposarcomas exhibited the radiographic characteristics of irregular and ill-defined adipose tissue, whereas only 12.5% of myxoid liposarcomas had the imaging characteristics. For the patients who exclusively underwent surgery, all of those with subtotal excisions experienced recurrence, 63.6% of marginal excisions recurred, and 50% of wide excisions resulted in recurrence. However, none of the patients who underwent marginal excisions or wide excisions combined with adjuvant radiotherapy exhibited recurrence. The analysis of magnetic resonance imaging findings in 3 patients who underwent neoadjuvant radiotherapy revealed that the tumor size remained stable in a patient with well-differentiated liposarcoma, whereas another patient with the same type of tumor exhibited a gradual increase in size. Conversely, a patient with myxoid liposarcoma experienced a significant reduction in tumor size following neoadjuvant radiotherapy.

CONCLUSION

Orbital liposarcoma demonstrated a propensity for developing in the extraocular muscle. The radiological images of orbital well-differentiated liposarcomas were characterized by irregular and ill-defined adipose tissue. Surgery combined with radiotherapy demonstrated potential in reducing recurrence rates. Notably, orbital myxoid liposarcoma exhibited greater sensitivity to radiotherapy compared to well-differentiated liposarcoma.

MRI Differential Diagnosis and Guidance for Puncture Biopsy of Musculoskeletal Dedifferentiated Liposarcoma and Well Differentiated Liposarcoma

Objective

The study aimed to investigate the significantly different imaging characteristics of musculoskeletal dedifferentiated liposarcoma (DDLP) and well differentiated liposarcoma (WDLP) on MRI, which in turn could guide puncture biopsy.

Materials and Methods

This study included 14 patients with DDLP and 16 patients with WDLP, all of whom were confirmed by histopathological examination. The MRI manifestations of these two pathologies were retrospectively reviewed and compared. Furthermore, a step-by-step procedure regarding preoperative puncture biopsy of fatty masses that are suspicious for WD/DD was designed.

Results

Fatty signals can be found in almost all WDs, with a greater proportion of non-fatty areas in DD compared to WD, and it is reasonable to consider WD more likely when the non-fatty areas of the tumor are <25% (p < 0.05), while it is reasonable to consider DD more likely when the non-fatty areas of the tumor are >50% (p < 0.05), and the MRI signals in DD are more complex, inhomogeneous (p < 0.01), usually showed significant enhancement (p < 0.01), and the margins of the tumor were usually indistinct (p < 0.01); and imaging features such as tumor size, vascularity, necrosis, and peritumoral edema did not serve as distinguishing features between the two (p > 0.05).

Conclusion

DD has a greater proportion of non-fatty components, with more complex and inhomogeneous MRI signals, and typically shows significant enhancement, with usually indistinct margins of the tumor, in which the inhomogeneous manifestations are associated with the histological components. The possibility of DD should be considered in fatty tumors with non-fatty areas > 25%, for which puncture biopsy is necessary, while simultaneous puncture of low, moderate, high-signal areas within the non-fatty area could improve the accuracy of preoperative puncture pathology.

Enormous myxoid/round cell liposarcoma: A case report

Myxoid/round cell liposarcomas (MRCLPS) are a rare soft tissue sarcoma. We report the largest sarcoma in our institutional history. We discuss the patient's surgical management and treatment of the tumor and challenges given its dimensions. Several complications arose following primary resection that were managed by a multidisciplinary team. Although MRCLPS can vary in size, large MRCLPS must be treated cautiously given the potential for complications. Additionally, multidisciplinary treatment of MRCLPS is essential in diagnosing and treating these complex cases.

UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

Case report: a case report of excision of giant lipoma in the posterior neck

Lipomas, benign tumors originating from the anomalous proliferation of adipocytes, predominantly emerge in regions rich in adipose tissue. However, their presence in the head and neck areas remains rare, constituting approximately 13% of all diagnosed lipoma cases. This study presents a case involving a substantial subcutaneous lipoma located at the posterior neck, measuring about 20 cm × 19 cm × 10 cm. The patient presented with swelling and pain in the back of the neck. And the considerable dimensions of this lipoma significantly impacted the patient's quality of life and aesthetic appearance. Concurrently, the patient exhibited symptoms indicative of degenerative cervical spine disease and cervical disc herniation. After admission, a comprehensive examination, including ultrasound, CT scan, and MRI, was conducted. Given the clinical complexity, the decision for surgical intervention was deemed essential. The surgical strategy entailed a meticulous total excision of the tumor through an incision made in the posterior cross-neck, coupled with the strategic removal of excess skin. To facilitate wound healing, postoperative management included the use of negative pressure drainage. Pathological examination conclusively identified the mass as a lipoma. Postoperative follow-ups indicated successful recovery, as evidenced by the restoration of the neck's aesthetic contour and the complete resolution of the previously observed restrictions in sagittal neck movement.

Clinical impact of whole-body MRI in staging and surveillance of patients with myxoid liposarcoma: a 14-year single-centre retrospective study

OBJECTIVE

To assess the clinical impact of regular whole-body magnetic resonance imaging (WBMRI) surveillance in myxoid liposarcoma patients.

METHODS

This was a retrospective cohort study of myxoid liposarcoma patients who underwent at least one WBMRI at our institution between October 2006 and December 2020. The effect of WBMRI on clinical management, namely treatment modification or additional diagnostic investigations was studied. A standardised WBMRI surveillance protocol was instituted in 2015. We compared patient outcomes for the metastatic patients who had and had not received regular WBMRI surveillance and performed survival analysis for both subgroups.

RESULTS

Of the 56 patients (60.7% male, median age: 48.1 years) who underwent 345 WBMRI, 17 (30.3%) had metastases, and 168 WBMRI were performed in this group. The median imaging follow-up for the entire cohort was 35 months; the metastatic group had a median follow-up of 42 months. WBMRI changed the clinical management in 13 (76.5%) metastatic patients, with 33 instances of treatment modification. Thirty-five lesions were labelled 'indeterminate,' 16 (45.7%) had additional investigations/interventions, and 4 (11.4%) were confirmed to be metastatic. Twenty-one metastatic lesions were missed initially on WBMRI and confirmed on subsequent WBMRI, of which 5 (23.8%) were clinically significant. The 5-year survival since the detection of metastasis was better in the regular surveillance subgroup (85.7% vs. 45%), but this was not statistically significant (p = 0.068). Five patients (8.9%) developed their first metastasis more than 5 years after diagnosing the primary lesion.

CONCLUSION

Regular WBMRI surveillance of myxoid liposarcoma patients considerably impacts clinical management by frequently influencing treatment decisions.

CLINICAL RELEVANCE STATEMENT

WBMRI has been recently recommended as an imaging option for the staging and surveillance of myxoid liposarcoma patients. Our study highlights the impact of regular WBMRI surveillance on the clinical management of these patients and how it affects their survival.

Dedifferentiated liposarcoma of the spermatic cord

A man in his 60s presented to an outside hospital with persistent groin pain and a scrotal mass which was thought to be a recurrent hernia. Three months after initial presentation, the patient was found to have dedifferentiated liposarcoma (LPS) of the spermatic cord. LPS of the spermatic cord is a rare entity; however, clinicians should have LPS on the differential diagnosis especially in men with recurrent scrotal pain and mass. If unrecognised, LPS is associated with a high degree of morbidity and mortality. LPS can be subdivided into well-differentiated LPS, dedifferentiated LPS, myxoid LPS and pleomorphic LPS. In patients with advanced or metastatic LPS, chemotherapy consisting of Adriamycin, ifosfamide and mesna is used despite LPS being relatively chemoresistant. Therapies inhibiting mouse double minute 2 homologue, an oncoprotein that is a negative regulator of the tumour suppressor p53, appear to be promising in preclinical trials.

Primary hepatic pleomorphic liposarcoma: Case report and literature review

Primary hepatic liposarcoma is an extremely rare malignant tumour derived from adipocytes and is part of the group of mesenchymal tumours. We present the case of a 43-year-old Hispanic male patient with a pleomorphic hepatic liposarcoma and absence of MDM2 gene amplification. Two years and six months after surgery, the patient is asymptomatic. The present case is the first report of this entity with positive immunohistochemical testing for p16, p53, S100, vimentin and absence of MDM2 gene amplification.

Gender Differences in Prognosis After Primary Resection for Retroperitoneal Liposarcoma

BACKGROUND

Current evidence regarding gender difference in retroperitoneal liposarcoma (RLPS) is scarce, so we sought to investigate whether gender may affect prognosis after primary resection of RLPS.

METHODS

We used the Surveillance, Epidemiology, and End Results (SEER) database to identify RLPS patients from January 1973 to December 2015. Multivariate cox proportional hazard analysis was adopted to generate adjusted hazard ratio (AHR) and 95% confidence intervals (CIs) of survival outcomes.

RESULTS

In total, 2108 RLPS patients, including 971 women and 1137 men, were identified, with a median follow-up of 45.0 (17.0-92.0) months. The 5-year and 10-year overall survival rates were 50.5% and 31.5% for men and 60.4% and 42.5% for women. The 5-year and 10-year disease-specific survival rates for men and women were 71.5%, 57.3% and 76.3%, 62.1%, respectively. We found men were associated with an increased risk of all-cause mortality (AHR 1.3, 95% CI 1.0-1.6, P = .017) but not disease-specific mortality (AHR 1.2, 95% CI .9-1.6, P = .246). The subgroup analyses revealed that men were associated with an increased risk of all-cause mortality in patients with low-grade tumors (AHR 1.8, 95% CI 1.3-2.5) or patients who received non-radical resection (AHR 1.6, 95% CI 1.2-2.1). In the subgroup of low-grade tumors, men were also associated with an increased risk of disease-specific mortality (AHR 2.0, 95% CI 1.2-3.3).

CONCLUSION

Men may have worse survival after primary resection of RLPS compared with women, especially in patients with low-grade tumors or patients who received non-radical resection. Gender-based disparities may deserve more attention in patients with RLPS.

Prediction of metabolites associated with somatic mutations in cancers by using genome-scale metabolic models and mutation data

BACKGROUND

Oncometabolites, often generated as a result of a gene mutation, show pro-oncogenic function when abnormally accumulated in cancer cells. Identification of such mutation-associated metabolites will facilitate developing treatment strategies for cancers, but is challenging due to the large number of metabolites in a cell and the presence of multiple genes associated with cancer development.

RESULTS

Here we report the development of a computational workflow that predicts metabolite-gene-pathway sets. Metabolite-gene-pathway sets present metabolites and metabolic pathways significantly associated with specific somatic mutations in cancers. The computational workflow uses both cancer patient-specific genome-scale metabolic models (GEMs) and mutation data to generate metabolite-gene-pathway sets. A GEM is a computational model that predicts reaction fluxes at a genome scale and can be constructed in a cell-specific manner by using omics data. The computational workflow is first validated by comparing the resulting metabolite-gene pairs with multi-omics data (i.e., mutation data, RNA-seq data, and metabolome data) from acute myeloid leukemia and renal cell carcinoma samples collected in this study. The computational workflow is further validated by evaluating the metabolite-gene-pathway sets predicted for 18 cancer types, by using RNA-seq data publicly available, in comparison with the reported studies. Therapeutic potential of the resulting metabolite-gene-pathway sets is also discussed.

CONCLUSIONS

Validation of the metabolite-gene-pathway set-predicting computational workflow indicates that a decent number of metabolites and metabolic pathways appear to be significantly associated with specific somatic mutations. The computational workflow and the resulting metabolite-gene-pathway sets will help identify novel oncometabolites and also suggest cancer treatment strategies.

A case of primary orbital liposarcoma with dedifferentiated transformation from a well-differentiated form

Purpose

Primary orbital liposarcomas are rare. To the best of our knowledge, only four cases of primary dedifferentiated liposarcomas of the orbit have been reported. Furthermore, there have been no reports of primary orbital liposarcomas transitioning from a highly differentiated to a dedifferentiated form. Here, we report a case of primary orbital liposarcoma that was well-differentiated at the time of initial resection at our hospital but had dedifferentiated on recurrence 10 years after the initial resection.

Observations

The patient was diagnosed with an inflammatory mass after an initial tumor resection by a previous physician at age 52. Thereafter, there were four recurrences (first to fourth recurrences), and the patient underwent five surgeries and radiotherapy. For the fifth recurrence, he first visited our hospital at age 64 and was diagnosed with a well-differentiated liposarcoma after undergoing tumor resection. When the tumor recurred 9 years later (the sixth recurrence), it was well-differentiated. When the tumor recurred (the seventh recurrence) six months after surgery at the age of 73 years, the patient underwent orbital exenteration because of rapid tumor growth, and pathological examination showed that the tissue had changed to a dedifferentiated liposarcoma.

Conclusions and Importance

Primary well-differentiated orbital liposarcoma may transform to a dedifferentiated form over time. The risk of dedifferentiation at recurrence should be considered in developing a treatment plan, even if the initial pathology is a well-differentiated liposarcoma.

Retroperitoneal dedifferentiated liposarcoma with rare heterologous low-grade osteosarcoma: A case report

Dedifferentiated liposarcoma is a high-grade entity developed from a preexisting or recurrent well-differentiated liposarcoma, and rarely, it may contain divergent differentiation. We presented the case of a 39-year-old woman with retroperitoneal dedifferentiated liposarcoma with heterologous low-grade osteosarcoma, possessing a special pattern of tumoral calcification.

Genetically engineered mouse model of pleomorphic liposarcoma: Immunophenotyping and histologic characterization

INTRODUCTION

Pleomorphic liposarcoma is a rare and aggressive subset of soft-tissue sarcomas with a high mortality burden. Local treatment largely consists of radiation therapy and wide surgical resection, but options for systemic therapy in the setting of metastatic disease are limited and largely ineffective, prompting exploration of novel therapeutic strategies and experimental models. As with other cancers, sarcoma cell lines and patient-derived xenograft models have been developed and used to characterize these tumors and identify therapeutic targets, but these models have inherent limitations. The establishment of genetically engineered mouse models represents a more realistic framework for reproducing clinically relevant conditions for studying pleomorphic liposarcoma.

METHODS

Trp53fl/fl/Rb1fl/fl/Ptenfl/fl (RPP) mice were used to reliably generate an immunocompetent model of mouse pleomorphic liposarcoma through Cre-mediated conditional silencing of the Trp53, Rb1, and Pten tumor suppressor genes. Evaluation of tumor-infiltrating lymphocytes was assessed with immunostaining for CD4, CD8, and PD-L1, and flow cytometry with analysis of CD45, CD3, CD4, CD8, CD19, F4/80, CD11b, and NKp46 sub-populations.

RESULTS

Mice reliably produced noticeable soft-tissue tumors in approximately 6 weeks with rapid tumor growth between 100 and 150 days of life, after which mice reached euthanasia criteria. Histologic features were consistent with pleomorphic liposarcoma, including widespread pleomorphic lipoblasts. Immunoprofiling and assessment of tumor-infiltrating lymphocytes was consistent with other soft-tissue sarcomas.

CONCLUSION

Genetically engineered RPP mice reliably produced soft-tissue tumors consistent with pleomorphic liposarcoma, which immunological findings similar to other soft-tissue sarcomas. This model may demonstrate utility in testing treatments for this rare disease, including immunomodulatory therapies.

An overview of 6-shogaol: new insights into its pharmacological properties and potential therapeutic activities

Ginger (Zingiber officinale Roscoe) has traditionally been used as a cooking spice and herbal medicine for treating nausea and vomiting. More recently, ginger was found to effectively reduce the risk of diseases such as gastroenteritis, migraine, gonarthritis, etc., due to its various bioactive compounds. 6-Shogaol, the pungent phenolic substance in ginger, is the most pharmacologically active among such compounds. The aim of the present study was to review the pharmacological characteristic of 6-shogaol, including the properties of anti-inflammatory, antioxidant and antitumour, and its corresponding molecular mechanism. With its multiple mechanisms, 6-shogaol is considered a beneficial natural compound, and therefore, this review will shed some light on the therapeutic role of 6-shogaol and provide a theoretical basis for the development and clinical application of 6-shogaol.

Ileum intussusception secondary to submucosal liposarcoma in adult：A case report

Intussusception in adults is a rare surgical emergency. Unlike in children, most adult intussusceptions arise from a pathological lead point. Ileal intussusception caused by a submucosal liposarcoma is a particularly rare phenomenon. This report describes the diagnosis and management of adult ileal intussusception secondary to submucosal liposarcoma in adult to provide a reference for future clinical work. A 64-year-old female presented to the emergency department with worsening abdominal pain associated with an 8 h history of intermittent vomiting. Based on physical examination, laboratory investigations, and computed tomography, the most likely diagnosis was ileal intussusception secondary to liposarcoma. Thus, emergency laparotomy was performed. During exploration, an ileal invagination was visualised approximately 30 cm from the ileocecal valve, and a flexible polypoid mass was palpable at the lead point of the intussusception. Subsequently, the patient underwent radical resection of pathological tissues with a primary end-to-end ileal anastomosis. Histopathological examination revealed a well-differentiated submucosal liposarcoma. Postoperatively, the patient recovered uneventfully and was doing well at the 6-month follow-up in the outpatient clinic. Thus, clinicians should consider the origin of submucosal liposarcomas in adult with intussusception. Once ileal intussusception secondary to submucosal liposarcoma is diagnosed, timely radical resection is recommended.

The pyroptosis-related signature predicts prognosis and influences the tumor immune microenvironment in dedifferentiated liposarcoma

Background

Dedifferentiated liposarcoma (DDL), a member of malignant mesenchymal tumors, has a high local recurrence rate and poor prognosis. Pyroptosis, a newly discovered programmed cell death, is tightly connected with the progression and outcome of tumor.

Objective

The aim of this study was to explore the role of pyroptosis in DDL.

Methods

We obtained the RNA sequencing data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression databases to identify different pyroptosis-related genes (PRGs) expression pattern. An unsupervised method for clustering based on PRGs was performed. Based on the result of cluster analysis, we researched clinical outcomes and immune microenvironment between clusters. The differentially expressed genes (DEGs) between the two clusters were used to develop a prognosis model by the LASSO Cox regression method, followed by the performance of functional enrichment analysis and single-sample gene set enrichment analysis. All of the above results were validated in the Gene Expression Omnibus (GEO) dataset.

Results

Forty-one differentially expressed PRGs were found between tumor and normal tissues. A consensus clustering analysis based on PRGs was conducted and classified DDL patients into two clusters. Cluster 2 showed a better outcome, higher immune scores, higher immune cells abundances, and higher expression levels in numerous immune checkpoints. DEGs between clusters were identified. A total of 5 gene signatures was built based on the DEGs and divided all DDL patients of the TCGA cohort into low-risk and high-risk groups. The low-risk group indicates greater inflammatory cell infiltration and better outcome. For external validation, the survival difference and immune landscape between the two risk groups of the GEO cohort were also significant. Receiver operating characteristic curves implied that the risk model could exert its function as an outstanding predictor in predicting DDL patients' prognoses.

Conclusion

Our findings revealed the clinical implication and key role in tumor immunity of PRGs in DDL. The risk model is a promising predictive tool that could provide a fundamental basis for future studies and individualized immunotherapy.

Genetic, Epigenetic and Transcriptome Alterations in Liposarcoma for Target Therapy Selection

Liposarcoma (LPS) is one of the most common adult soft-tissue sarcomas (STS), characterized by a high diversity of histopathological features as well as to a lesser extent by a spectrum of molecular abnormalities. Current targeted therapies for STS do not include a wide range of drugs and surgical resection is the mainstay of treatment for localized disease in all subtypes, while many LPS patients initially present with or ultimately progress to advanced disease that is either unresectable, metastatic or both. The understanding of the molecular characteristics of liposarcoma subtypes is becoming an important option for the detection of new potential targets and development novel, biology-driven therapies for this disease. Innovative therapies have been introduced and they are currently part of preclinical and clinical studies. In this review, we provide an analysis of the molecular genetics of liposarcoma followed by a discussion of the specific epigenetic changes in these malignancies. Then, we summarize the peculiarities of the key signaling cascades involved in the pathogenesis of the disease and possible novel therapeutic approaches based on a better understanding of subtype-specific disease biology. Although heterogeneity in liposarcoma genetics and phenotype as well as the associated development of resistance to therapy make difficult the introduction of novel therapeutic targets into the clinic, recently a number of targeted therapy drugs were proposed for LPS treatment. The most promising results were shown for CDK4/6 and MDM2 inhibitors as well as for the multi-kinase inhibitors anlotinib and sunitinib.

Low local recurrence rates following marginal surgical resection of non-coelomic Atypical Lipomatous Tumours/Well-differentiated Liposarcomas

INTRODUCTION

High rates of local recurrence (LR) have been reported following resection of extremity Atypical lipomatous tumours/Well-differentiated liposarcomas (ALTs). This retrospective study of patients who underwent resection of primary deep extremity and trunk ALTs at a specialist sarcoma centre aims to assess morbidity and factors associated with low local recurrence rates (LRR).

METHODS

To review a homogeneous cohort of patients with low-grade disease, tumours with known high-risk histological features were excluded. Prognostic variables potentially influencing local recurrence (LR) (age, size, site, margin status, and histological findings) were analysed. Endpoints were LR, distant recurrence (DR) and local disease-free survival (LDFS).

RESULTS

127 patients were identified, with median follow-up of 54 months (0-235). Median tumour size was 17.5 cm (5-36). 85 % occurred in the lower limb. 93.7 % underwent marginal resection. No patients received radiotherapy. Median hospital stay was 3 days (0-16). 7.9 % returned to theatre for evacuation of haematoma or infected seroma and 18.1 % had outpatient seroma aspiration. Surgical margins were R0/R1 in 93.7 % of patients and R2 in 6.3 % with a LR rate of 8.4 % and 75 % respectively at median time of 54 months. One- and 5-year LDFS was 100 % and 88.4 %, respectively. DR rate was 0.8 % (1/127) this patient had pleomorphic liposarcomatous transformation on recurrence and subsequently developed distant metastases. No patients died of disease.

CONCLUSION

Function-preserving marginal resection of non-coelomic ALTs has low morbidity, low LR and extremely low rates of distant relapse. Patients with lower limb ALT were found to have significantly lower LR, which may impact follow-up protocols.

MDM2-p53 in liposarcoma: The need for targeted therapies with novel mechanisms of action

Well-differentiated and dedifferentiated liposarcomas (WDLPS and DDLPS) are rare tumors that arise from lipocytes in soft tissue. There is a high unmet need in patients with these liposarcomas given poor outcomes, particularly for DDLPS. WDLPS and DDLPS share important genetic and histological characteristics - most notably, the amplification of the 2 genes MDM2 and CDK4. Both genes are considered oncogenes because of their ability to shut down tumor suppressor pathways. There are multiple therapeutic approaches that aim to target MDM2 and CDK4 activity for the purpose of restoring intrinsic tumor suppressor cellular response and terminating oncogenesis. However, current understanding of the molecular mechanisms involved in WDLPS and DDLPS pathology is limited. In recent years, significant efforts have been made to refine and implement targeted therapy for this patient population. The use of patient-derived cell and tumor xenograft models has been an important tool for recapitulating WDLPS and DDLPS biology. These models also offer valuable insights for drug development and drug combination studies. Here we offer a review of the current understanding of WDLPS and DDLPS biology and its therapeutic implications.

PROGNOSTIC IMPLICATIONS OF PD-L1 EXPRESSION AND LOSS OF PTEN IN PATIENTS WITH RHABDOMYOSARCOMA, EWING'S SARCOMA AND OSTEOSARCOMA

BACKGROUND

In children, osteosarcoma (OS), Ewing's sarcoma (ES), and rhabdomyosarcoma (RMS) are the most common sarcomas. A link between the anti-programmed death ligand-1 PD-L1 and the tumor suppressor phosphatase and tensin homologue (PTEN) expression has been described in many tumors. The aim of this work is to determine clinicopathological relationships and the possible prognostic significance of PD-L1 and PTEN expression in rhabdomyosarcoma (RMS), Ewing's sarcoma (ES), and osteosarcoma (OS).

MATERIALS AND METHODS

Expression of PD-L1 and PTEN were examined by immunohistochemistry in 45 archival RMS, ES, and OS cases.

RESULTS

The positive expression of PD-L1 was found in 16.7% and 31.6% of ES and OS, respectively. The negative PD-L1 was related to a substantially longer survival in ES cases (p = 0.045), but positive PD-L1 expression was significantly associated with the increased tumor stage and vascular invasion in the OS cases (p = 0.005 and p = 0.002), respectively. On the other hand, PTEN loss was strongly associated with deep tumor, high tumor grade, and recurrence in RMS (p = 0.002, p = 0.045, and p = 0.026, respectively). However, PTEN loss was significantly absent in ES as tumor grade increased (p = 0.031). It is noteworthy that tumor recurrence, the loss of PTEN, and positive PD-L1 were all considered predictive factors in OS patients (p = 0.045, p = 0.032, and p = 0.02, respectively).

CONCLUSIONS

In children, OS and ES have positive PD-L1 expression, which has an independent unfavorable prognostic effect and raises the possibility of using PD-L1 as a therapeutic target. OS, ES, and RMS prognosis are all predicted by PTEN loss.

Retroperitoneal liposarcoma: unveiling diagnostic delays and multimodal treatment dilemmas

Liposarcomas are a prevalent subtype of soft tissue sarcomas, constituting less than 1% of all malignancies. Originating in the adipose tissue, they can manifest in various locations and are categorized by the World Health Organization into several subtypes: well-differentiated liposarcomas, dedifferentiated liposarcomas, myxoid liposarcomas, pleomorphic liposarcomas and mixed-type liposarcomas. These tumors typically affect middle-aged and older individuals, and their incidence has been progressively increasing over the years. As liposarcomas advance they tend to encase blood vessels and major organs, particularly in the retroperitoneal area. Often asymptomatic initially, symptoms arise as the tumor reaches a considerable size, exerting pressure on adjacent tissues and organs. This report features a 54-year-old patient incidentally diagnosed with a substantial retroperitoneal tumor extending to the antero-lateral abdominal wall and inner thigh via the right inguinal ligament. The patient, with a previous three-year history of a right inguinal mass, sought acute care for a perianal abscess The histological examination revealed morphological aspects consistent with a low-grade myxoid liposarcoma. While surgery remains the primary treatment for retroperitoneal liposarcomas, controversies exist regarding the role of radiotherapy and chemotherapy in improving survival rates. This case highlights the challenges in managing retroperitoneal tumors and underscores the importance of a personalized, multidisciplinary approach to optimize patient outcomes.

Pseudocystic myxoid liposarcoma of the posterior chest wall - a rare case report

Introduction and importance

Liposarcoma (LPS) is a common soft-tissue sarcoma predominantly diagnosed in adults, arising from malignant adipose cells. Among its various subtypes, myxoid LPS (MLPS) stands out as the second most frequent, accounting for ~30% of all LPS cases. This particular subtype typically manifests in males between the ages of 40 and 50 and is commonly found in the lower extremities. Although rare, MLPS may also occur in the head, neck, and infrequently in the back. Chest wall LPS cases are also sparsely reported.

Case presentation

In this report, we present a case of MLPS in a 69-year-old male patient who presented with a complaint of firm swelling on the right posterior chest wall, which was progressively increasing in size over the past 10 years. The tumour was located in the posterior chest wall on the left side, and further diagnostic evaluation using computed tomography (CT) and MRI was conducted to identify its characteristics and extent.

Clinical discussion

The use of CT scanning plays a crucial role in differentiating between various lipomatous tumour types, aiding in the identification and classification of MLPS. However, MRI emerges as a more effective technique for detecting microscopic fat compared to CT or ultrasonography, providing valuable insights for accurate diagnosis and treatment planning.

Conclusion

Surgery remains the primary therapeutic approach for managing LPSs, including MLPS. Adjuvant preoperative radiation is recommended due to its significant sensitivity and potential for improved outcomes. Given the rarity of this presentation and the varied anatomical locations, a multidisciplinary approach is paramount in effectively managing such cases. Medical practitioners should collaborate closely, considering the unique challenges posed by MLPS to ensure optimal patient care and treatment outcomes.

Massive dedifferentiated thigh liposarcoma growing for 10 years and extending into the retroperitoneum: a case report

Liposarcomas are rare, malignant tumors of adipocyte differentiation. Surgery is the main treatment method. We are reporting a rare case of a 65- year- old female patient with a massive dedifferentiated thigh liposarcoma that was growing for 10 years and spread to the retroperitoneum.

Primary Orbital Myxoid Liposarcoma

Although liposarcoma is the most prevalent soft tissue sarcoma in adults, head and neck liposarcomas are rare and account for less than 5% of all liposarcomas. The primary orbital location is even more exceptional, with fewer than 100 cases documented in the medical literature. Given the scarcity of cases of orbital liposarcoma and the limited familiarity of physicians and pathologists with this pathology, there is an increased risk of non-diagnosis or misdiagnosis, which may lead to inappropriate patient management. To address these challenges, we present a case of primary orbital myxoid liposarcoma and subsequently discuss the primary findings of this case based on the evidence documented in the medical literature. This comprehensive text is designed to serve as a valuable resource for healthcare professionals and pathologists, with the goal of promoting both clinical suspicion and accurate diagnosis and treatment of this rare condition in future cases.

PDE3A Is a Highly Expressed Therapy Target in Myxoid Liposarcoma

Liposarcomas (LPSs) are a heterogeneous group of malignancies that arise from adipose tissue. Although LPSs are among the most common soft-tissue sarcoma subtypes, precision medicine treatments are not currently available. To discover LPS-subtype-specific therapy targets, we investigated RNA sequenced transcriptomes of 131 clinical LPS tissue samples and compared the data with a transcriptome database that contained 20,218 samples from 95 healthy tissues and 106 cancerous tissue types. The identified genes were referred to the NCATS BioPlanet library with Enrichr to analyze upregulated signaling pathways. PDE3A protein expression was investigated with immunohistochemistry in 181 LPS samples, and PDE3A and SLFN12 mRNA expression with RT-qPCR were investigated in 63 LPS samples. Immunoblotting and cell viability assays were used to study LPS cell lines and their sensitivity to PDE3A modulators. We identified 97, 247, and 37 subtype-specific, highly expressed genes in dedifferentiated, myxoid, and pleomorphic LPS subtypes, respectively. Signaling pathway analysis revealed a highly activated hedgehog signaling pathway in dedifferentiated LPS, phospholipase c mediated cascade and insulin signaling in myxoid LPS, and pathways associated with cell proliferation in pleomorphic LPS. We discovered a strong association between high PDE3A expression and myxoid LPS, particularly in high-grade tumors. Moreover, myxoid LPS samples showed elevated expression levels of SLFN12 mRNA. In addition, PDE3A- and SLFN12-coexpressing LPS cell lines SA4 and GOT3 were sensitive to PDE3A modulators. Our results indicate that PDE3A modulators are promising drugs to treat myxoid LPS. Further studies are required to develop these drugs for clinical use.

Discoidin Domain Receptor Tyrosine Kinase 1 (DDR1) Is a Novel Therapeutic Target in Liposarcoma: A Tissue Microarray Study

BACKGROUND

Liposarcoma is the most commonly diagnosed subtype of soft tissue sarcoma. As these tumors often arise near vital organs and neurovascular structures, complete resection can be challenging; consequently, recurrence rates are high. Additionally, available chemotherapeutic agents have shown limited benefit and substantial toxicities. There is, therefore, a clear and unmet need for novel therapeutics for liposarcoma. Discoidin domain receptor tyrosine kinase 1 (DDR1) is involved in adhesion, proliferation, differentiation, migration, and metastasis in several cancers. However, the expression and clinical importance of DDR1 in liposarcoma are unknown.

QUESTIONS/PURPOSES

The purposes of this study were to assess (1) the expression, (2) the association between DDR1 and survival, and (3) the functional roles of DDR1 in liposarcoma.

METHODS

The correlation between DDR1 expression in tumor tissues and clinicopathological features and survival was assessed via immunohistochemical staining of a liposarcoma tissue microarray. It contained 53 samples from 42 patients with liposarcoma and 11 patients with lipoma. The association between DDR1 and survival in liposarcoma was analyzed by Kaplan-Meier plots and log-rank tests. The DDR1 knockout liposarcoma cell lines were generated by CRISPR-Cas9 technology. The DDR1-specific and highly selective DDR1 inhibitor 7RH was applied to determine the impact of DDR1 expression on liposarcoma cell growth and proliferation. In addition, the effect of DDR1 inhibition on liposarcoma growth was further accessed in a three-dimensional cell culture model to mimic DDR1 effects in vivo.

RESULTS

The results demonstrate elevated expression of DDR1 in all liposarcoma subtypes relative to benign lipomas. Specifically, high DDR1 expression was seen in 55% (23 of 42) of liposarcomas and no benign lipomas. However, DDR1 expression was not found to be associated with poor survival in patients with liposarcoma. DDR1 knockout or treatment of 7RH showed decreased liposarcoma cell growth and proliferation.

CONCLUSION

DDR1 is aberrantly expressed in liposarcoma, and it contributes to several markers of oncogenesis in these tumors.

CLINICAL RELEVANCE

This work supports DDR1 as a promising therapeutic target in liposarcoma.

Unveiling the role of GAS41 in cancer progression

GAS41, a member of the human YEATS domain family, plays a pivotal role in human cancer development. It serves as a highly promising epigenetic reader, facilitating precise regulation of cell growth and development by recognizing essential histone modifications, including histone acetylation, benzoylation, succinylation, and crotonylation. Functional readouts of these histone modifications often coincide with cancer progression. In addition, GAS41 functions as a novel oncogene, participating in numerous signaling pathways. Here, we summarize the epigenetic functions of GAS41 and its role in the carcinoma progression. Moving forward, elucidating the downstream target oncogenes regulated by GAS41 and the developing small molecule inhibitors based on the distinctive YEATS recognition properties will be pivotal in advancing this research field.

Case Report: Primary low-grade dedifferentiated liposarcoma of the urinary bladder with molecular confirmation

Liposarcomas originating in the urinary bladder are extremely rare. Only six cases of bladder liposarcoma have been reported, and all have been described as myxoid liposarcomas. Notably, none of the patients underwent molecular testing. Here, we report a dedifferentiated liposarcoma (DDL) that occurred in the urinary bladder, primarily in a 69-year-old Chinese woman, with infrequent low-grade dedifferentiation. Computed tomography (CT) revealed an ill-defined solid mass in the anterior bladder wall. The patient underwent a partial bladder resection. Histologically, the tumor cells with mild-to-moderate nuclear atypia were arranged in fascicular and storiform patterns, mimicking a low-grade fibroblastic tumor. In addition, scattered small foci of typical lipoma-like well-differentiated components were identified. Immunohistochemically, the tumor tested positivity for MDM2, CDK4, and p16. Fluorescence in situ hybridization revealed MDM2 gene amplification in the neoplastic cells. Whole-exome sequencing showed that this tumor also harbored CDK4, TSPAN31, and JUN amplification. At the latest follow-up (85 months after surgery), the patient was alive, with no evidence of disease. To the best of our knowledge, this is the first example of a molecularly confirmed primary bladder liposarcoma and the first case of DDL at this site.

Primary dedifferentiated liposarcoma of the pancreas: A case report and literature review

BACKGROUND

Dedifferentiated liposarcoma (DDLPS) is a high-grade invasive tumor that more commonly occurs in the retroperitoneum, followed by the thighs and groin. DDLPS in the pancreas is very rare.

CASE SUMMARY

A patient underwent CT examination due to hidden pain in the upper abdomen, which revealed a pancreatic space occupying lesion of unknown nature. Based on the patient's preoperative medical history, physical examination, and auxiliary examination, it was considered that there was a huge space occupying lesion in the head and neck of the pancreas, with clear boundaries and surgical indications. The patient underwent pancreaticoduodenectomy at our hospital, and the postoperative pathology revealed a DDLPS of the pancreas. Three months after the surgery, tumor recurrence occurred. Dacarbazine combined with epirubicin chemotherapy had a poor effect, and the patient passed away 18 mo later.

CONCLUSION

Due to the fact that DDLPS of the pancreas is usually not significantly responsive to radiotherapy and chemotherapy, the currently most effective treatment method for DDLPS of the pancreas is resection with negative margin under a microscope. However, due to the deep location of liposarcoma in the pancreas and its proximity to many surrounding organs, it is difficult to completely remove the tumor, and many patients may develop regional recurrence.

IGF2BP3 as a Prognostic Biomarker in Well-Differentiated/Dedifferentiated Liposarcoma

BACKGROUND

Although IGF2BP3 has been implicated in tumorigenesis and poor outcomes in multiple cancers, its role in soft-tissue sarcoma (STS) remains unknown. Preliminary data have suggested an association with IGF2BP3 expression among patients with well-differentiated/dedifferentiated liposarcoma (WD/DD LPS), a disease where molecular risk stratification is lacking.

METHODS

We examined the survival associations of IGF2BP3 via univariate and multivariate Cox regression in three unique datasets: (1) the Cancer Genome Atlas (TCGA), (2) an in-house gene microarray, and (3) an in-house tissue microarray (TMA). A fourth dataset, representing an independent in-house TMA, was used for validation.

RESULTS

Within the TCGA dataset, IGF2BP3 expression was a poor prognostic factor uniquely in DD LPS (OS 1.6 vs. 5.0 years, p = 0.009). Within the microarray dataset, IGF2BP3 expression in WD/DD LPS was associated with worse survival (OS 7.7 vs. 21.5 years, p = 0.02). IGF2BP3 protein expression also portended worse survival in WD/DD LPS (OS 3.7 vs. 13.8 years, p < 0.001), which was confirmed in our validation cohort (OS 2.7 vs. 14.9 years, p < 0.001). In the multivariate model, IGF2BP3 was an independent risk factor for OS, (HR 2.55, p = 0.034).

CONCLUSION

IGF2BP3 is highly expressed in a subset of WD/DD LPS. Across independent datasets, IGF2BP3 is also a biomarker of disease progression and worse survival.

A century of retroperitoneal soft-tissue sarcoma research: From single center experience to precision oncology? A bibliometric analysis of past, present, and future perspectives

BACKGROUND

Increasing publication numbers in the biomedical field led to an improvement of patient care in many aspects but are challenging for scientists when integratively processing data of their fields. Using bibliometric analyses, the present study assesses the productivity and predominant topics in retroperitoneal soft-tissue sarcoma (RPS) research across the past 122 years, thereby identifying crucial questions to address in future RPS research.

METHODS

Using the Web of Science Core Collection, 1018 RPS-associated publications from 1900 to 2022 were identified and analyzed regarding key bibliometric variables using the Bibliometrix R package and the VOSviewer software.

RESULTS

A continuous increase in RPS-associated publication numbers can be noticed over the time, which is strongly pronounced from 2005 onwards, and is characterized by a multinationally driven collaborative clinical research focus. The research primarily reflects progression regarding surgical techniques, histology-based therapy, radiotherapy regimens, and identification of prognostic clinicopathological factors. This progression is accompanied with improved overall survival of RPS patients. However, a paucity of RPS-specific basic/translational research indicates that such research might be additionally needed to better understand the pathophysiology of RPS and with that to enable the development of personalized therapies and to further improve patient outcome.

CONCLUSION

Increasing publication numbers of multinationally driven clinical RPS research are accompanied with improved overall survival of RPS patients, highlighting the importance of international collaborations to facilitate future clinical trials. However, this bibliometric analysis reveals a lack of RPS-specific basic/translational research which is needed to further improve patient outcome in the context of precision oncology.

Whole exome sequencing of well-differentiated liposarcoma and dedifferentiated liposarcoma in older woman: a case report

Background

Common kinds of soft tissue sarcomas (STS) include well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS). In this case, we present a comprehensive clinical profile of a patient who underwent multiple recurrences during the progression from WDLPS to DDLPS.

Case presentation

A 62-year-old Asian female underwent retroperitoneal resection of a large tumor 11 years ago, the initial pathology revealed a fibrolipoma-like lesion. Over the next six years, the patient underwent three resections for recurrence of abdominal tumors. Postoperative histology shows mature adipose tissue with scattered "adipoblast"-like cells with moderate-to-severe heterogeneous spindle cells, pleomorphic cells, or tumor giant cells. Immunohistochemistry (IHC) demonstrated positive staining for MDM2 and CDK4, confirming that the abdominal tumor was WDLPS and gradually progressing to DDLPS. Post-operative targeted sequencing and IHC confirmed the POC1B::ROS1 fusion gene in DDLPS. Whole-exome sequencing (WES) revealed that WDLPS and DDLPS shared similar somatic mutations and copy number variations (CNVs), whereas DDLPS had more mutated genes and a higher and more concentrated amplification of the chromosome 12q region. Furthermore, somatic mutations in DDLPS were significantly reduced after treatment with CDK4 inhibitors, while CNVs remained elevated.

Conclusion

Due to the high likelihood of recurrence of liposarcoma, various effective treatments should be taken into consideration even if surgery is the primary treatment for recurrent liposarcoma. To effectively control the course of the disease following surgery, combination targeted therapy may be a viable alternative to chemotherapy and radiotherapy in the treatment of liposarcoma.

Chemotherapeutic drugs for soft tissue sarcomas: a review

Despite the low incidence of soft tissue sarcomas (STSs), hundreds of thousands of new STS cases are diagnosed annually worldwide, and approximately half of them eventually progress to advanced stages. Currently, chemotherapy is the first-line treatment for advanced STSs. There are difficulties in selecting appropriate drugs for multiline chemotherapy, or for combination treatment of different STS histological subtypes. In this study, we first comprehensively reviewed the efficacy of various chemotherapeutic drugs in the treatment of STSs, and then described the current status of sensitive drugs for different STS subtypes. anthracyclines are the most important systemic treatment for advanced STSs. Ifosfamide, trabectedin, gemcitabine, taxanes, dacarbazine, and eribulin exhibit certain activities in STSs. Vinca alkaloid agents (vindesine, vinblastine, vinorelbine, vincristine) have important therapeutic effects in specific STS subtypes, such as rhabdomyosarcoma and Ewing sarcoma family tumors, whereas their activity in other subtypes is weak. Other chemotherapeutic drugs (methotrexate, cisplatin, etoposide, pemetrexed) have weak efficacy in STSs and are rarely used. It is necessary to select specific second- or above-line chemotherapeutic drugs depending on the histological subtype. This review aims to provide a reference for the selection of chemotherapeutic drugs for multi-line therapy for patients with advanced STSs who have an increasingly long survival.

Proteasome Inhibition Sensitizes Liposarcoma to MDM2 Inhibition with Nutlin-3 by Activating the ATF4/CHOP Stress Response Pathway

Liposarcoma is the most commonly occurring soft-tissue sarcoma and is frequently characterized by amplification of chromosome region 12q13-15 harboring the oncogenes MDM2 and CDK4. This unique genetic profile makes liposarcoma an attractive candidate for targeted therapeutics. While CDK4/6 inhibitors are currently employed for treatment of several cancers, MDM2 inhibitors have yet to attain clinical approval. Here, we report the molecular characterization of the response of liposarcoma to the MDM2 inhibitor nutlin-3. Treatment with nutlin-3 led to upregulation of two nodes of the proteostasis network: the ribosome and the proteasome. CRISPR/Cas9 was used to perform a genome-wide loss of function screen that identified PSMD9, which encodes a proteasome subunit, as a regulator of response to nutlin-3. Accordingly, pharmacologic studies with a panel of proteasome inhibitors revealed strong combinatorial induction of apoptosis with nutlin-3. Mechanistic studies identified activation of the ATF4/CHOP stress response axis as a potential node of interaction between nutlin-3 and the proteasome inhibitor carfilzomib. CRISPR/Cas9 gene editing experiments confirmed that ATF4, CHOP, and the BH3-only protein, NOXA, are all required for nutlin-3 and carfilzomib-induced apoptosis. Furthermore, activation of the unfolded protein response using tunicamycin and thapsigargin was sufficient to activate the ATF4/CHOP stress response axis and sensitize to nutlin-3. Finally, cell line and patient-derived xenograft models demonstrated combinatorial effects of treatment with idasanutlin and carfilzomib on liposarcoma growth in vivo. Together, these data indicate that targeting of the proteasome could improve the efficacy of MDM2 inhibitors in liposarcoma.

SIGNIFICANCE

Targeting the proteasome in combination with MDM2 inhibition activates the ATF4/CHOP stress response axis to induce apoptosis in liposarcoma, providing a potential therapeutic approach for the most common soft-tissue sarcoma.

Notch signaling regulates a metabolic switch through inhibiting PGC-1α and mitochondrial biogenesis in dedifferentiated liposarcoma

Human dedifferentiated liposarcoma (DDLPS) is a rare but lethal cancer with no driver mutations being identified, hampering the development of targeted therapies. We and others recently reported that constitutive activation of Notch signaling through overexpression of the Notch1 intracellular domain (NICDOE) in murine adipocytes leads to tumors resembling human DDLPS. However, the mechanisms underlying the oncogenic functions of Notch activation in DDLPS remains unclear. Here, we show that Notch signaling is activated in a subset of human DDLPS and correlates with poor prognosis and expression of MDM2, a defining marker of DDLPS. Metabolic analyses reveal that murine NICDOE DDLPS cells exhibit markedly reduced mitochondrial respiration and increased glycolysis, mimicking the Warburg effect. This metabolic switch is associated with diminished expression of peroxisome proliferator-activated receptor gamma coactivator 1α (Ppargc1a, encoding PGC-1α protein), a master regulator of mitochondrial biogenesis. Genetic ablation of the NICDOE cassette rescues the expression of PGC-1α and mitochondrial respiration. Similarly, overexpression of PGC-1α is sufficient to rescue mitochondria biogenesis, inhibit the growth and promote adipogenic differentiation of DDLPS cells. Together, these data demonstrate that Notch activation inhibits PGC-1α to suppress mitochondrial biogenesis and drive a metabolic switch in DDLPS.

Impact of supraphysiologic MDM2 expression on chromatin networks and therapeutic responses in sarcoma

Amplification of MDM2 on supernumerary chromosomes is a common mechanism of P53 inactivation across tumors. Here, we investigated the impact of MDM2 overexpression on chromatin, gene expression, and cellular phenotypes in liposarcoma. Three independent regulatory circuits predominate in aggressive, dedifferentiated tumors. RUNX and AP-1 family transcription factors bind mesenchymal gene enhancers. P53 and MDM2 co-occupy enhancers and promoters associated with P53 signaling. When highly expressed, MDM2 also binds thousands of P53-independent growth and stress response genes, whose promoters engage in multi-way topological interactions. Overexpressed MDM2 concentrates within nuclear foci that co-localize with PML and YY1 and could also contribute to P53-independent phenotypes associated with supraphysiologic MDM2. Importantly, we observe striking cell-to-cell variability in MDM2 copy number and expression in tumors and models. Whereas liposarcoma cells are generally sensitive to MDM2 inhibitors and their combination with pro-apoptotic drugs, MDM2-high cells tolerate them and may underlie the poor clinical efficacy of these agents.

Insight of a lipid metabolism prognostic model to identify immune landscape and potential target for retroperitoneal liposarcoma

Introduction

The exploration of lipid metabolism dysregulation may provide novel perspectives for retroperitoneal liposarcoma (RPLS). In our study, we aimed to investigate potential targets and facilitate further understanding of immune landscape in RPLS, through lipid metabolism-associated genes (LMAGs) based prognostic model.

Methods

Gene expression profiles and corresponding clinical information of 234 cases were enrolled from two public databases and the largest retroperitoneal tumor research center of East China, including cohort-TCGA (n=58), cohort-GSE30929 (n=92), cohort-FD (n=50), cohort-scRNA-seq (n=4) and cohort-validation (n=30). Consensus clustering analysis was performed to identify lipid metabolism-associated molecular subtypes (LMSs). A prognostic risk model containing 13 LMAGs was established using LASSO algorithm and multivariate Cox analysis in cohort-TCGA. ESTIMATE, CIBERSORT, XCELL and MCP analyses were performed to visualize the immune landscape. WGCNA was used to identify three hub genes among the 13 model LMAGs, and preliminarily validated in both cohort-GSE30929 and cohort-FD. Moreover, TIMER was used to visualize the correlation between antigen-presenting cells and potential targets. Finally, single-cell RNA-sequencing (scRNA-seq) analysis of four RPLS and multiplexed immunohistochemistry (mIHC) were performed in cohort-validation to validate the discoveries of bioinformatics analysis.

Results

LMS1 and LMS2 were characterized as immune-infiltrated and -excluded tumors, with significant differences in molecular features and clinical prognosis, respectively. Elongation of very long chain fatty acids protein 2 (ELOVL2), the enzyme that catalyzed the elongation of long chain fatty acids, involved in the maintenance of lipid metabolism and cellular homeostasis in normal cells, was identified and negatively correlated with antigen-presenting cells and identified as a potential target in RPLS. Furthermore, ELOVL2 was enriched in LMS2 with significantly lower immunoscore and unfavorable prognosis. Finally, a high-resolution dissection through scRNA-seq was performed in four RPLS, revealing the entire tumor ecosystem and validated previous findings.

Discussion

The LMS subgroups and risk model based on LMAGs proposed in our study were both promising prognostic classifications for RPLS. ELOVL2 is a potential target linking lipid metabolism to immune regulations against RPLS, specifically for patients with LMS2 tumors.

Increasing differential diagnosis between lipoma and liposarcoma through radiomics: a narrative review

Soft tissue sarcomas (STSs) are rare, heterogeneous, and very often asymptomatic diseases. Their diagnosis is fundamental, as is the identification of the degree of malignancy, which may be high, medium, or low. The Italian Medical Oncology Association and European Society of Medical Oncology (ESMO) guidelines recommend magnetic resonance imaging (MRI) because the clinical examination is typically ineffective. The diagnosis of these rare diseases with artificial intelligence (AI) techniques presents reduced datasets and therefore less robust methods. However, the combination of AI techniques with radiomics may be a new angle in diagnosing rare diseases such as STSs. Results obtained are promising within the literature, not only for the performance but also for the explicability of the data. In fact, one can make tumor classification, site localization, and prediction of the risk of developing metastasis. Thanks to the synergy between computer scientists and radiologists, linking numerical features to radiological evidence with excellent performance could be a new step forward for the diagnosis of rare diseases.

The proteomic landscape of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare and diverse mesenchymal cancers with limited treatment options. Here we undertake comprehensive proteomic profiling of tumour specimens from 321 STS patients representing 11 histological subtypes. Within leiomyosarcomas, we identify three proteomic subtypes with distinct myogenesis and immune features, anatomical site distribution and survival outcomes. Characterisation of undifferentiated pleomorphic sarcomas and dedifferentiated liposarcomas with low infiltrating CD3 + T-lymphocyte levels nominates the complement cascade as a candidate immunotherapeutic target. Comparative analysis of proteomic and transcriptomic profiles highlights the proteomic-specific features for optimal risk stratification in angiosarcomas. Finally, we define functional signatures termed Sarcoma Proteomic Modules which transcend histological subtype classification and show that a vesicle transport protein signature is an independent prognostic factor for distant metastasis. Our study highlights the utility of proteomics for identifying molecular subgroups with implications for risk stratification and therapy selection and provides a rich resource for future sarcoma research.

Bioinformatics Screen Reveals Gli-Mediated Hedgehog Signaling as an Associated Pathway to Poor Immune Infiltration of Dedifferentiated Liposarcoma

Liposarcomas are the most diagnosed soft tissue sarcoma, with most cases consisting of well-differentiated (WDLPS) or dedifferentiated (DDLPS) histological subtypes. While both tumor subtypes can have clinical recurrence due to incomplete resections, DDLPS often has worse prognosis due to a higher likelihood of metastasis compared to its well-differentiated counterpart. Unfortunately, targeted therapeutic interventions have lagged in sarcoma oncology, making the need for molecular targeted therapies a promising future area of research for this family of malignancies. In this work, previously published data were analyzed to identify differential pathways that may contribute to the dedifferentiation process in liposarcoma. Interestingly, Gli-mediated Hedgehog signaling appeared to be enriched in dedifferentiated adipose progenitor cells and DDLPS tumors, and coincidentally Gli1 is often co-amplified with MDM2 and CDK4, given its genomic proximity along chromosome 12q13-12q15. However, we find that Gli2, but not Gli1, is differentially expressed between WDLPS and DDLPS, with a noticeable co-expression signature between Gli2 and genes involved in ECM remodeling. Additionally, Gli2 co-expression had a noticeable transcriptional signature that could suggest Gli-mediated Hedgehog signaling as an associated pathway contributing to poor immune infiltration in these tumors.

Treatment of De-Differentiated Liposarcoma in the Era of Immunotherapy

Well-differentiated/de-differentiated liposarcoma (WDLPS/DDLPS) is one of the most common histologic subtypes of soft tissue sarcoma (STS); however, treatment options remain limited. WDLPS and DDLPS both exhibit the characteristic amplification of chromosome region 12q13-15, which contains the genes CDK4 and MDM2. DDLPS exhibits higher amplification ratios of these two and carries additional genomic lesions, including the amplification of chromosome region 1p32 and chromosome region 6q23, which may explain the more aggressive biology of DDLPS. WDLPS does not respond to systemic chemotherapy and is primarily managed with local therapy, including multiple resections and debulking procedures whenever clinically feasible. In contrast, DDLPS can respond to chemotherapy drugs and drug combinations, including doxorubicin (or doxorubicin in combination with ifosfamide), gemcitabine (or gemcitabine in combination with docetaxel), trabectedin, eribulin, and pazopanib. However, the response rate is generally low, and the response duration is usually short. This review highlights the clinical trials with developmental therapeutics that have been completed or are ongoing, including CDK4/6 inhibitors, MDM2 inhibitors, and immune checkpoint inhibitors. This review will also discuss the current landscape in assessing biomarkers for identifying tumors sensitive to immune checkpoint inhibitors.

Phosphorylation of IWS1 by AKT maintains liposarcoma tumor heterogeneity through preservation of cancer stem cell phenotypes and mesenchymal-epithelial plasticity

Chemotherapy remains the mainstay of treatment for patients with advanced liposarcoma (LPS), but response rates are only 25% and the overall survival at 5 years is dismal at 20-34%. Translation of other therapies have not been successful and there has been no significant improvement in prognosis for nearly 20 years. The aberrant activation of the phosphatidylinositol 3-kinase (PI3K)/AKT pathway has been implicated in the aggressive clinical behavior LPS and in resistance to chemotherapy, but the precise mechanism remains elusive and efforts to target AKT clinically have failed. Here we show that the AKT-mediated phosphorylation of the transcription elongation factor IWS1, promotes the maintenance of cancer stem cells in both cell and xenograft models of LPS. In addition, phosphorylation of IWS1 by AKT contributes to a "metastable" cell phenotype, characterized by mesenchymal/epithelial plasticity. The expression of phosphorylated IWS1 also promotes anchorage-dependent and independent growth, cell migration, invasion, and tumor metastasis. In patients with LPS, IWS1 expression is associated with reduced overall survival, increased frequency of recurrence, and shorter time to relapse after resection. These findings indicate that IWS1-mediated transcription elongation is an important regulator of human LPS pathobiology in an AKT-dependent manner and implicate IWS1 as an important molecular target to treat LPS.

Long-term results of huge deep-seated liposarcoma in the thigh: Two case reports

RATIONALE

Liposarcoma is an uncommon malignant tumor that develops in the fatty tissue; thus, the long-term follow-up results of extremely large liposarcomas in the submuscular layer of the thigh have rarely been reported. Here we share the course and outcome of 2 cases of a huge deep-seated liposarcoma in the thigh.

PATIENT CONCERNS

Two patients visited our clinic, each with a deep-seated mass in the thigh. First, a 44-year-old man presented to the outpatient clinic with a left thigh mass. Approximately 1 year later, an 80-year-old man presented to the outpatient clinic with a right posterior thigh mass.

DIAGNOSIS

Magnetic resonance imaging revealed an approximately 14 × 8 × 21 cm well-differentiated liposarcoma between the sartorius and iliopsoas muscle and an approximately 14 × 12 × 31.5 cm lipomatous mass in the posterior compartment of the right thigh involving the right adductor muscles. After complete marginal resection, an excisional biopsy was performed to confirm the diagnosis.

INTERVENTIONS

Both patients underwent complete marginal resection without chemotherapy or radiotherapy.

OUTCOMES

A biopsy showed a 20 × 17 × 7 cm well-differentiated, well-encapsulated liposarcoma in the 44-year-old man and a 30 × 17 × 10 cm well-differentiated liposarcoma in the 80-year-old man. These patients have achieved approximately 61 and 44 months of recurrence-free survival to date, respectively.

LESSONS

Here we described the long-term outcomes of 2 patients with a huge deep-seated liposarcoma in the lower extremity. Complete marginal excision of well-differentiated liposarcoma can achieve excellent recurrence-free survival.

The Conundrum of Dedifferentiation in a Liposarcoma at a Peculiar Location: A Case Report and Literature Review

Dedifferentiated liposarcoma of the deep soft tissue of the lower extremities is an infrequent finding. Myxoid liposarcoma is considered the most common soft tissue neoplasia arising in this anatomic region. Divergent differentiation usually occurs within well-differentiated liposarcoma and is exceedingly rare in a myxoid liposarcoma. We report a 32-year-old man who developed a dedifferentiated liposarcoma of the thigh on the background of a pre-existing myxoid liposarcoma. The gross examination of the surgical specimen showed a 11/7/2 cm tumour mass with solid tan-grey areas and focal myxoid degeneration. The microscopic examination revealed a malignant lipogenic proliferation, containing round cells with hyperchromatic nuclei and atypical lipoblasts, confined to the basophilic stroma with a myxoid aspect. Abrupt transition towards a hypercellular, non-lipogenic area consisting of highly pleomorphic spindle cells with atypical mitotic figures was also noted. Immunohistochemical staining was performed. Tumour cells in the lipogenic area were intensely positive for S100 and p16, and CD34 staining highlighted an arborizing capillary network. The dedifferentiated tumour areas showed positive MDM2 and CDK4 staining within neoplastic cells, with the Ki 67 proliferation marker expressed in approximately 10% of the cells. Wild-type TP53 protein expression pattern was documented. Thus, the diagnosis of a dedifferentiated liposarcoma was established. This paper aims to provide further knowledge about liposarcomas with divergent differentiation at peculiar locations, emphasizing the importance of histopathologic examination and immunohistochemical analysis for establishing the diagnosis and assessing the therapeutic response and prognosis of this condition.