Advanced well-differentiated/dedifferentiated liposarcomas: role of chemotherapy and survival

A first-in-human phase I study of a novel MDM2/p53 inhibitor alrizomadlin in advanced solid tumors

BACKGROUND

The mouse double minute 2 homolog (MDM2) oncogene exerts oncogenic activities in many cancers and represents a potential therapeutic target. This trial evaluated the safety, pharmacokinetics, pharmacodynamics, and preliminary efficacy of alrizomadlin (APG-115), a novel MDM2/p53 inhibitor, in patients with advanced solid tumors.

PATIENTS AND METHODS

Patients with histologically confirmed advanced solid tumors who had progressed to standard treatment or lacked effective therapies were recruited. Alrizomadlin was administered once daily every other day for 21 days of a 28-day cycle until disease progression or intolerable toxicity.

RESULTS

A total of 21 patients were enrolled and treated with alrizomadlin; 57.1% were male and the median age was 47 (25-60) years. The maximum tolerated dose of alrizomadlin was 150 mg and the recommended phase II dose was 100 mg. One patient in the 200-mg cohort experienced dose-limiting toxicity of thrombocytopenia and febrile neutropenia. The most common grade 3/4 treatment-related adverse events were thrombocytopenia (33.3%), lymphocytopenia (33.3%), neutropenia (23.8%), and anemia (23.8%). Alrizomadlin demonstrated approximately linear pharmacokinetics (dose range 100-200 mg) and was associated with increased plasma macrophage inhibitory cytokine-1, indicative of p53 pathway activation. Of the 20 assessable patients, 2 [10%, 95% confidence interval (CI) 1.2% to 31.7%] patients achieved partial response and 10 (50%, 95% CI 27.2% to 72.8%) showed stable disease. The median progression-free survival was 6.1 (95% CI 1.7-10.4) months, which was significantly longer in patients with wild-type versus mutant TP53 (7.9 versus 2.2 months, respectively; P < 0.001). Among patients with MDM2 amplification and wild-type TP53, the overall response rate was 25% (2/8) and the disease control rate was 100% (8/8).

CONCLUSIONS

Alrizomadlin had an acceptable safety profile and demonstrated promising antitumor activity in MDM2-amplified and TP53 wild-type tumors. This study supports further exploration of alrizomadlin with recommended doses of 100 mg q.o.d. in 21 days on and 7 days off regimen.

Surgical outcomes of major vascular resection for retroperitoneal liposarcoma from a high‑volume sarcoma center: a propensity score matching analysis

PURPOSE

Radical resection of retroperitoneal liposarcoma (RLPS) may necessitate vascular resection and reconstruction. The study was conducted to assess surgical outcomes of surgery for RLPS with major vascular involvement.

METHODS

Patients with RLPS who underwent surgical resection at the Sarcoma Center of Peking University Cancer Hospital between April 2011 and December 2022 were identified from a prospectively maintained database. Patients were classified into two groups: vascular resection and non-vascular resection groups. A propensity score matching analysis was performed to eliminate baseline differences between the groups. Surgical details and postoperative outcomes were analyzed. Furthermore, prognostic factors for local recurrence-free survival (LRFS) and overall survival (OS) were assessed.

RESULTS

Overall, 199 patients were identified and the median follow-up period was 48 (interquartile range [IQR] 45-69) months. Vascular resection was performed in 42 (21%) patients, 25 of whom had vascular infiltration. A total of 39 patients had vascular replacement and 3 patients underwent partial resection (side-wall resection). Vascular resection was burdened by higher rates of major morbidity (38% vs. 14%, p < 0.001) and 30-day mortality (7.1% vs. 1.3%, p = 0.005). After propensity-matched analysis, patients who underwent vascular resection had 5-year LRFS and OS rates comparable to those without vascular involvement. Major vascular resection was not an independent risk factor for LRFS or OS.

CONCLUSIONS

Although accompanied by increased risks of major morbidity and mortality, the major vascular resection enabled radical resection in patients with advanced RLPS, affording comparable 5-year LRFS and OS rates compared to those who did not.

Current unmet needs in locally advanced (unresectable) or metastatic dedifferentiated liposarcoma, the relevance of progression-free survival as clinical endpoint, and expectations for future clinical trial design: an international Delphi consensus report

BACKGROUND

Locally advanced (unresectable) or metastatic dedifferentiated liposarcoma (DDLPS) is a common presentation of liposarcoma. Despite established diagnostic and treatment guidelines for DDLPS, critical clinical gaps remain driven by diagnostic challenges, symptom burden and the lack of targeted, safe and effective treatments. The objective of this study was to gather expert opinions from Europe and the United States on the management, unmet needs and expectations for clinical trial design as well as the value of progression-free survival (PFS) in this disease. Other aims included raising awareness and educate key stakeholders across healthcare systems.

MATERIALS AND METHODS

An international panel of 12 sarcoma key opinion leaders (KOLs) was recruited. The study consisted of two rounds of surveys with pre-defined statements. Experts scored each statement on a 9-point Likert scale. Consensus agreement was defined as ≥75% of experts scoring a statement with ≥7. Revised statements were discussed in a consensus meeting.

RESULTS

Consensus was reached on 43 of 55 pre-defined statements across disease burden, treatment paradigm, unmet needs, value of PFS and its association with overall survival (OS), and cross-over trial design. Twelve statements were deprioritised or merged with other statements. There were no statements where experts disagreed.

CONCLUSION

This study constitutes the first international Delphi panel on DDLPS. It aimed to explore KOL perception of the disease burden and unmet need in DDLPS, the value of PFS, and its potential translation to OS benefit, as well as the relevance of a cross-over trial design for DDLPS therapies. Results indicate an alignment across Europe and the United States regarding DDLPS management, unmet needs, and expectations for clinical trials. Raising awareness of critical clinical gaps in relation to DDLPS can contribute to improving patient outcomes and supporting the development of innovative treatments.

Recurrent paratesticular liposarcoma: a case report

Introduction and importance

Paratesticular liposarcoma (PTL) is a rare condition, with fewer than 200 cases reported worldwide. It is a malignant tumor that originates from fat tissue with high risk of recurrence. Herein, the authors present a contralateral recurrence of a treated PTL. To the best of the authors' knowledge, in the current literature, there are few cases reported with recurrent PTL.

Case presentation

The authors report the case of a 62-year-old man who presented with a rapidly growing painless right hemiscrotal swelling. Clinical and radiographic evidence suggested the presence of two paratesticular tumors. The patient underwent a radical orchidectomy with resection of the two tumors through an inguinal approach. The histologic examination revealed a sclerosing, well-differentiated liposarcoma. The decision of the multidisciplinary consultation meeting was not to do adjuvant treatment. A follow-up of 12 months showed recurrence of the contralateral scrotum revealed by an FDG-PET/scan.

Clinical discussion

PTL, a rare spermatic cord tumor, affects adults aged 50-60, often presenting with scrotal swelling. Diagnosis involves ultrasound, computed tomography, and magnetic resonance imaging. Surgical intervention, including radical orchiectomy and adjuvant radiotherapy, is common for management, while the role of chemotherapy is inconclusive. High-grade subtypes carry a higher recurrence risk.

Conclusion

PTL is often misdiagnosed preoperatively. It is typically managed through radical orchidectomy, which includes wide excision and high ligation to ensure free surgical margins and avoid recurrence. The role of adjuvant therapy remains debatable. Despite a generally favorable prognosis, long-term follow-up is crucial because of the elevated risk of recurrence.

Well-differentiated liposarcomas and dedifferentiated liposarcomas: Systemic treatment options for two sibling neoplasms

Well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS) account for 60 % of all liposarcomas, reflecting the heterogeneity of this type of sarcoma. Genetically, both types of liposarcomas are characterized by the amplification of MDM2 and CDK4 genes, which indicates an important molecular event with diagnostic and therapeutic relevance. In both localized WDLPS and DDLPS of the retroperitoneum and the extremities, between 25 % and 30 % of patients have local or distant recurrence, even when perioperatively treated, with clear margins present. The systemic treatment of WDLPS and DDLPS remains a challenge, with anthracyclines as the gold standard for first-line treatment. Several regimens have been tested with modest results regarding their efficacy. Herein we discuss the systemic treatment options for WDLPS and DDLPS and review their reported clinical efficacy results.

Intraperitoneal Liposarcoma: A Case Report and Literature Review of a Rare Entity

Liposarcoma is a rare soft-tissue neoplasm originating from adipocytes. The exact cause of liposarcoma is unknown and symptoms vary depending on the tumor's location. A 49-year-old man presented to the emergency room complaining of epigastric pain radiating to the back and right upper quadrant. Cross-sectional imaging revealed a large upper abdominal mass that was thought to be a gastrointestinal stromal tumor (GIST) arising from the duodenum at first. The patient underwent en-bloc resection of the mass and was planned for adjuvant chemotherapy. Subsequently, multiple tissue samples were examined, leading to the final diagnosis of de-differentiated liposarcoma. The patient eventually developed multiple recurrences and was subjected to re-resection surgeries and three different chemotherapy regimens. Given the rarity of the disease, no standardized therapy plan is available, highlighting the need for more case reports/series and trials to broaden our understanding of this disease.

SAR-096: Phase II Clinical Trial of Ribociclib in Combination with Everolimus in Advanced Dedifferentiated Liposarcoma (DDL) and Leiomyosarcoma (LMS)

PURPOSE

Dedifferentiated liposarcoma (DDL) and leiomyosarcoma (LMS) are two common subtypes of soft-tissue sarcoma, a rare group of diseases for which new treatments are needed. Chemotherapy remains the standard option for advanced disease. Targeting cyclin-dependent kinase 4 and 6 (CDK4/6) in DDL and mTOR in LMS is of biologic interest. When combined, the CDK4 inhibitor ribociclib and the mTOR inhibitor everolimus have shown synergistic growth inhibition in multiple tumor models, suggesting that this combination could be beneficial in patients.

PATIENTS AND METHODS

This was a single arm, open label, multicenter phase II study of the combination of ribociclib and everolimus. Patients were enrolled into one of two cohorts: DDL or LMS with intact Rb. The primary endpoint was progression-free rate (PFR) at 16 weeks. Secondary endpoints included progression-free survival (PFS) and overall survival, safety and biomarker analyses.

RESULTS

In the DDL cohort, 33.3% [95% confidence interval (CI), 15.6%-55.3%] of patients were progression-free at 16 weeks. Median PFS in this cohort was 15.4 weeks (95% CI, 8-36 weeks) with 2 partial responses. In the LMS cohort the PFR at 16 weeks was 29.2% (95% CI, 12.6%-51.1%). Median PFS in this cohort was 15.7 weeks (95% CI, 7.7-NA). Most common toxicities included fatigue (66.7%), anorexia (43.8%), and hyperglycemia (43.8%). Concordance between Rb testing methodologies was poor.

CONCLUSIONS

The combination of ribociclib and everolimus demonstrates activity in DDL with prolonged stable disease (≥16 weeks) meeting the primary endpoint. Notably partial responses were observed. The primary endpoint was not reached in the LMS cohort. The combination was well tolerated with expected side effects.

Clinical characteristics and management of primary retroperitoneal sarcoma: A literature review

Retroperitoneal sarcoma (RPS) is a rare tumor classified into many histological types. It is also often detected only after it has grown to a considerable size and requires extensive resection of the surrounding organs, making it difficult to offer optimal patient-tailored management. Evidence supporting specific treatment modalities for RPS is insufficient, owing to its rarity. The Japanese clinical practice guidelines for RPS were published in December 2021, with the aim of accumulating existing evidence and indicating the optimal practice for RPS. These guidelines provide important clinical questions (CQs) concerning the diagnosis and treatment of RPS. This review, with a particular focus on primary RPS, attempts to introduce clinical problems in the diagnosis and treatment of RPS and to assess those problems along with the CQs in the guidelines. According to these guidelines, although chemotherapy and radiotherapy are expected to have therapeutic effects, the level of evidence to support these treatments is not very high at present. Accordingly, complete resection of the tumor is the first and only option for managing primary RPS. However, as with other tumors, the demand for multidisciplinary treatment for RPS is increasing. These guidelines will undoubtedly represent a milestone in clinical practice in relation to RPS in the future, and further evidence is expected to be accumulated based on the CQs that have been proposed.

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.

Advancements in MDM2 inhibition: Clinical and pre-clinical investigations of combination therapeutic regimens

Cancer cells often depend on multiple pathways for their growth and survival, resulting in therapeutic resistance and the limited effectiveness of treatments. Combination therapy has emerged as a favorable approach to enhance treatment efficacy and minimize acquired resistance and harmful side effects. The murine double minute 2 (MDM2) protein regulates cellular proliferation and promotes cancer-related activities by negatively regulating the tumor suppressor protein p53. MDM2 aberrations have been reported in a variety of human cancers, making it an appealing target for cancer therapy. As a result, several small-molecule MDM2 inhibitors have been developed and are currently being investigated in clinical studies. Nevertheless, it has been shown that the inhibition of MDM2 alone is inadequate to achieve long-term suppression of tumor growth, thus prompting the need for further investigation into combination therapeutic strategies. In this review, possible clinical and preclinical MDM2 combination inhibitor regimens are thoroughly analyzed and discussed. It provides a rationale for combining MDM2 inhibitors with other therapeutic approaches in the management of cancer, taking into consideration ongoing clinical trials that evaluate the combination of MDM2 inhibitors. The review explores the current status of MDM2 inhibitors in combination with chemotherapy or targeted therapy, as well as promising approach of combining MDM2 inhibitors with immunotherapy. In addition, it investigates the function of PROTACs as MDM2 degraders in cancer treatment. A comprehensive examination of these combination regimens highlights the potential for advancing MDM2-inhibitor therapy and improving clinical outcomes for cancer patients and establishes the foundation for future research and development in this promising area of study.

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.

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.

Sequential Targeting of Retinoblastoma and DNA Synthesis Pathways Is a Therapeutic Strategy for Sarcomas That Can Be Monitored in Real Time

Treatment strategies with a strong scientific rationale based on specific biomarkers are needed to improve outcomes in patients with advanced sarcomas. Suppression of cell-cycle progression through reactivation of the tumor suppressor retinoblastoma (Rb) using CDK4/6 inhibitors is a potential avenue for novel targeted therapies in sarcomas that harbor intact Rb signaling. Here, we evaluated combination treatment strategies (sequential and concomitant) with the CDK4/6 inhibitor abemacicib to identify optimal combination strategies. Expression of Rb was examined in 1,043 sarcoma tumor specimens, and 50% were found to be Rb-positive. Using in vitro and in vivo models, an effective two-step sequential combination strategy was developed. Abemaciclib was used first to prime Rb-positive sarcoma cells to reversibly arrest in G1 phase. Upon drug removal, cells synchronously traversed to S phase, where a second treatment with S-phase targeted agents (gemcitabine or Wee1 kinase inhibitor) mediated a synergistic response by inducing DNA damage. The response to treatment could be noninvasively monitored using real-time positron emission tomography imaging and serum thymidine kinase activity. Collectively, these results show that a novel, sequential treatment strategy with a CDK4/6 inhibitor followed by a DNA-damaging agent was effective, resulting in synergistic tumor cell killing. This approach can be readily translated into a clinical trial with noninvasive functional imaging and serum biomarkers as indicators of response and cell cycling.

SIGNIFICANCE

An innovative sequential therapeutic strategy targeting Rb, followed by treatment with agents that perturb DNA synthesis pathways, results in synergistic killing of Rb-positive sarcomas that can be noninvasively monitored.

Brightline-1: phase II/III trial of the MDM2-p53 antagonist BI 907828 versus doxorubicin in patients with advanced DDLPS

Dedifferentiated liposarcoma (DDLPS) is a rare, aggressive liposarcoma associated with poor prognosis. First-line treatment for advanced/metastatic DDLPS is systemic chemotherapy, but efficacy is poor and toxicities substantial. Most DDLPS tumors have amplification of the MDM2 gene, which encodes a negative regulator of the p53 suppressor protein. BI 907828 is a highly potent, oral MDM2-p53 antagonist that inhibits the interaction between p53 and MDM2, thereby restoring p53 activity. BI 907828 has shown promising activity in preclinical studies and in a phase Ia/Ib study in patients with solid tumors, particularly those with DDLPS. This manuscript describes the rationale and design of an ongoing multicenter, randomized, phase II/III trial (Brightline-1; NCT05218499) evaluating BI 907828 versus doxorubicin as first-line treatment for advanced DDLPS.

Retrospective evaluation of the role of gemcitabine-docetaxel in well-differentiated and dedifferentiated liposarcoma

OBJECTIVE

Well-differentiated (WDLPS) and dedifferentiated liposarcoma (DDLPS) account for the majority of liposarcomas. Although gemcitabine-docetaxel is used as second-line treatment in soft tissue sarcomas, its efficacy in WDLPS/DDLPS is not established. This study retrospectively analyzed the efficacy of gemcitabine regimens in WDLPS/DDLPS.

METHODS

All patients with WDLPS or DDLPS who received gemcitabine-based chemotherapy at our institution between September 2002 and January 2021 were included. Response was evaluated by an independent radiologist using RECIST 1.1. The Kaplan-Meier method was used to estimate distributions of survival outcomes and log-rank tests were used to compare survival outcomes between subgroups.

RESULTS

Sixty-five WDLPS/DDLPS patients were included. Seven patients (10.8%) received a gemcitabine-based regimen more than once, totaling 72 treatments. The median age at the start of treatment was 66 years (range 32-80 years). Sixty-five (90.3%) regimens were gemcitabine-docetaxel, and 7 (9.7%) were gemcitabine alone. Majorities of treatments were for disease that was recurrent/metastatic (86.1%), was abdominal/retroperitoneal (83.3%), and had DDLPS components (88.9%), while 25.0% of treatments were for multifocal disease. The overall response rate was 9.7% (7/72). All responses were in patients with documented DDLPS. The median time to progression was 9.2 months (95% CI 5.3-12.3 months). The median overall survival from the start of therapy was 18.8 months (95% CI 13.1-32.4 months).

CONCLUSION

Gemcitabine-docetaxel is an efficacious second-line treatment for DDLPS. Though cross study comparisons are not advisable, response to gemcitabine-docetaxel compares favorably to current standard options trabectedin and eribulin. This combination is a valid comparator arm for future second-line trials in DDLPS.

Lipidomics and Transcriptomics Differ Liposarcoma Differentiation Characteristics That Can Be Altered by Pentose Phosphate Pathway Intervention

Liposarcoma (LPS) is a rare and heterogeneous malignancy of adipocytic origin. Well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS) are two of the most common subtypes, showing similar genetic characterizations but distinct biological behaviors and clinical prognosis. Compared to WDLPS, DDLPS is more aggressive and has the potential of metastasis, as the malignant adipocytic tumor's metabolic changes may have taken place during the tumorigenesis of LPSs. Therefore, to investigate the lipid alterations between the two subtypes, high-resolution liquid chromatography tandem mass spectrometry (LC-MS/MS) based untargeted lipidomic analysis was performed onto LPS tissues from 6 WDLPS and 7 DDLPS patients. The lipidomic analysis showed the upregulated phosphatidylcholines and phosphoethanolamines in DDLPS, and the upregulated triglycerides and diglycerides in WDLPS, which might be due to the uncompleted adipocytic dedifferentiation leading to such tumorigenesis. Such a finding was also confirmed by the similarity comparison of two LPS subtypes to the transcriptome of stromal vascular fraction at different differentiation stages. Transcriptomic analysis also demonstrated that metabolic pathways including the pentose phosphate pathway (PPP) were upregulated in WDLPS compared to DDLPS. Therefore, the cell line LPS853 was treated with the PPP inhibitor 6-aminonicotinamide ex vivo and the proliferation and invasion of LPS853 was significantly promoted by PPP inhibition, suggesting the potential role of PPP in the development and differentiation of LPS. In conclusion, this study described the altered lipid profiles of WDLPS and DDLPS for the first time, revealing the different differentiation stages of the two subtypes and providing a potential metabolic target for LPS treatment.

Immunotherapy for liposarcoma: emerging opportunities and challenges

Liposarcoma (LPS) is a rare adipocyte-derived malignancy accounting for 20% of all soft tissue sarcomas. Although surgery and chemotherapy are the standard treatment for LPS, the large tumor burden and high recurrence rate make it difficult to treat, especially when the disease progresses. With the progress of immunotherapies in other tumors such as melanoma and lung cancer, interest has been risen in exploring immunotherapy for LPS. This review discusses the understanding of the tumor microenvironment of LPS; the current status of immunotherapy in LPS, including immune checkpoint inhibitors, adoptive cell therapy, cancer vaccines, oncolytic viruses and combination therapies; and the future directions for exploiting strategies to make the effect of immunotherapy stronger and more durable.

Management of pelvic sarcoma

Pelvic sarcomas are a rare and heterogenous group of tumors divided into two groups: soft tissue sarcomas and bone sarcomas. Soft tissue sarcomas of the pelvis include most commonly liposarcoma, leiomyosarcoma, gastrointestinal stromal tumors, malignant peripheral nerve sheath tumors, and solitary fibrous tumors. Bone sarcomas of the pelvis most commonly include osteosarcoma and chondrosarcoma. Multidisciplinary treatment at a center experienced in the treatment of sarcoma is essential. Management is dictated by histologic type and grade. Surgical resection with wide margins is the cornerstone of treatment for pelvic sarcomas, although this is often challenging due to anatomic constraints of the pelvis. Multimodal treatment is critical due to the high risk of local recurrence in the pelvis.

Surgery of intraabdominal giant dedifferentiated liposarcoma of ascending colon mesentery: A rare case report

Introduction

Liposarcoma, a lipogenic tumor of large deep-seated connective tissue space, presents the most common type of soft tissue sarcoma arising in the retroperitoneum. Liposarcoma that arises from colonic mesentery is especially a very rare disease. The present case describes a surgery of giant dedifferentiated liposarcoma at ascending colon mesentery.

Presentation of case

A 47-year-old South Korean man was admitted and presented with palpable abdominal mass. Abdominal pelvic computed tomography scan revealed a huge mass at his right sided abdomen (about 25 × 19 cm sized mass at right abdomen with encapsulation). After the surgery, the entire mass was completely excised en bloc with the ascending colon. The specimen consisted of multinodular, pinkish tanned, focally myxoid tissue, which measured up to 25.5 × 19 × 12.5 cm. Final pathological analysis reported dedifferentiated liposarcoma (high grade sarcoma) with MDM2 and CDK2 (+) in immunohistochemistry.

Conclusion

The present case report concerns a 47-year-old male with giant dedifferentiated liposarcoma arising from colonic mesentery and achieved en-bloc resection of liposarcoma with right hemicolectomy.

•

Dedifferentiated liposarcoma arising from colonic mesentery is a rare form of the soft tissue sarcoma.

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In giant dedifferentiated liposarcoma, grossly complete resection is known as the better prognostic factor.

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liposarcoma excision with right hemicolectomy was inevitable for this case to achieve the complete resection due to colon wall invasion.

Is preoperative CT-guided biopsy a valuable tool in the diagnostic workup of patients with visceral and retroperitoneal sarcoma?

PURPOSE

We aimed to analyze the diagnostic accuracy of preoperative CT-guided biopsy to identify patients that might profit from neoadjuvant chemotherapy in a specialized high-volume sarcoma center.

MATERIAL AND METHODS

We retrospectively reviewed all patients with suspected soft tissue tumors of the abdomen cavity including the retroperitoneum, who received CT-guided biopsy followed by surgical tumor resection. Sensitivity, specificity, PPV and NPV were calculated in all patients with abdominal sarcomas at our hospital. A subgroup analysis was performed for patients with liposarcoma.

RESULTS

A total of 82 patients (35 female, 47 male, age: 62.0 ± 14.7) received preoperative CT-guided biopsy followed by surgical resection. Overall accordance of CT-guided biopsy to identify final histology was 77 %. CT-guided biopsy revealed the diagnosis of liposarcoma in 23 patients whereas final analysis of the surgical specimen identified liposarcoma in 29 patients. Here, sensitivity, specificity, PPV and NPV was 79.3 %, 100.0 %, 100.0 % and 89.8 % respectively. Subgroup analysis revealed a better accuracy for correctly identifying patients with well-differentiated liposarcoma than patients with dedifferentiated liposarcoma (75.0 % vs 62.5 %). In patients with other sarcoma, sensitivity, specificity, PPV, NPV and diagnostic accuracy was 87.5 %, 95.5 %, 82.4 % and 96.9 %, respectively.

CONCLUSION

CT-guided biopsy in a specialized high-volume sarcoma center is an accurate and effective method to assess patients with abdominal sarcoma and especially abdominal liposarcoma. Therefore, it is an indispensable tool in the pretherapeutic workup process. Nevertheless, our study underlines the previously reported difficulties in dedifferentiated liposarcoma diagnostics, whereby these patient cohort would profit the most from a neoadjuvant therapy regime.

Selinexor in Advanced, Metastatic Dedifferentiated Liposarcoma: A Multinational, Randomized, Double-Blind, Placebo-Controlled Trial

PURPOSE

Antitumor activity in preclinical models and a phase I study of patients with dedifferentiated liposarcoma (DD-LPS) was observed with selinexor. We evaluated the clinical benefit of selinexor in patients with previously treated DD-LPS whose sarcoma progressed on approved agents.

METHODS

SEAL was a phase II-III, multicenter, randomized, double-blind, placebo-controlled study. Patients age 12 years or older with advanced DD-LPS who had received two-five lines of therapy were randomly assigned (2:1) to selinexor (60 mg) or placebo twice weekly in 6-week cycles (crossover permitted). The primary end point was progression-free survival (PFS). Patients who received at least one dose of study treatment were included for safety analysis (ClinicalTrials.gov identifier: NCT02606461).

RESULTS

Two hundred eighty-five patients were enrolled (selinexor, n = 188; placebo, n = 97). PFS was significantly longer with selinexor versus placebo: hazard ratio (HR) 0.70 (95% CI, 0.52 to 0.95; one-sided P = .011; medians 2.8 v 2.1 months), as was time to next treatment: HR 0.50 (95% CI, 0.37 to 0.66; one-sided P < .0001; medians 5.8 v 3.2 months). With crossover, no difference was observed in overall survival. The most common treatment-emergent adverse events of any grade versus grade 3 or 4 with selinexor were nausea (151 [80.7%] v 11 [5.9]), decreased appetite (113 [60.4%] v 14 [7.5%]), and fatigue (96 [51.3%] v 12 [6.4%]). Four (2.1%) and three (3.1%) patients died in the selinexor and placebo arms, respectively. Exploratory RNA sequencing analysis identified that the absence of CALB1 expression was associated with longer PFS with selinexor compared with placebo (median 6.9 v 2.2 months; HR, 0.19; P = .001).

CONCLUSION

Patients with advanced, refractory DD-LPS showed improved PFS and time to next treatment with selinexor compared with placebo. Supportive care and dose reductions mitigated side effects of selinexor. Prospective validation of CALB1 expression as a predictive biomarker for selinexor in DD-LPS is warranted.

Lipoma and Its Doppelganger: The Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma

Lipomatous tumors are among the most common soft tissue lesions encountered by the general surgeon. Shared history and clinical presentation make differentiation between benign lipomas and low-grade liposarcomas a diagnostic dilemma. This article reviews the epidemiology, clinical history, diagnostic workup, management, natural history, and surveillance of benign lipomas and atypical lipomatous tumors/well-differentiated liposarcomas. Although it is important that aggressive, potentially malignant atypical lipomatous tumors and liposarcomas be managed in a multidisciplinary, preferably high-volume setting, it is equally as important for the nonspecialist general surgeon to be familiar with lipoma and its doppelganger-the well-differentiated liposarcoma.

New Drug Approvals for Sarcoma in the Last 5 Years

Sarcoma and locally aggressive connective tissue tumors are a complex group of diseases with a growing number of histotypes in the most recent WHO classification. Most of these tumors are rare (incidence <6/10⁵/y) or ultrarare (<1/10⁶/y). Despite their rarity, sarcomas are often good models for the development of personalized medicine, and a large number of new clinical trials in select histotypes and molecular subsets were reported during the past 5 years, leading to a faster rate of new drug approvals. We analyzed the published literature and the abstracts reported in major congresses dedicated to sarcoma and connective tissue tumor management in the last 5 years. Several targeted therapies, cytotoxic treatments, and immunotherapies have demonstrated activity in dedicated histologic and molecular subtypes of sarcomas. The majority of the studies for ultrarare entities are uncontrolled studies, as a consequence of the rarity of histotypes, but randomized controlled trials were available in the less rare histotypes. Most successful trials were based on biomarker selection, which were often driver molecular alterations, while a large number of ongoing research programs aim to identify biomarkers in parallel to new drug development. Availability of the new agents varies across countries. This article describes the new drugs that made it through to the finish line and new agents with promising activity that are in later stages of investigation in the large family of malignant connective tissue tumors.

Real-world use of palbociclib monotherapy in retroperitoneal liposarcomas at a large volume sarcoma center

Palbociclib has been evaluated in early phase trials for well-differentiated liposarcoma (WDLPS) and dedifferentiated liposarcoma (DDLPS) patients, with reported median progression-free survival (PFS) of 18 weeks. Here, we report on real-world use and surgical outcomes associated with palbociclib treatment. We retrospectively reviewed 61 consecutive patients with retroperitoneal WDLPS (n = 14) or DDLPS (n = 47) treated with palbociclib monotherapy between 1 March 2016 and 28 February 2021 at The University of Texas MD Anderson Cancer Center. At palbociclib initiation, median age was 64 (interquartile range [IQR] 56-72). In WDLPS and DDLPS cohorts, the median number of prior systemic treatments was 0 (IQR 0-0) and 2 (IQR 0-4), respectively. Median number of prior surgeries was 2 (WDLPS IQR 1-2.75) and 2 (DDLPS IQR 1-3). Median PFS was 9.2 (WDLPS IQR 3.9-21.9) and 2.6 months (DDLPS IQR 2.0-6.1), with median time on treatment of 7.4 months (WDLPS IQR 3.5-14.2) and 2.7 months (DDLPS IQR 2.0-5.7). Twelve patients ultimately underwent surgical resection. Resections were macroscopically complete (R0/R1) in half (n = 6/12), among whom only one patient experienced relapse after resection (median follow-up 7.5 months). All patients who underwent macroscopically incomplete resections progressed after surgery with median time to progression of 3.3 months (IQR 2.3-4.4). Surgery after palbociclib treatment was not associated with improved overall survival. Efficacy of palbociclib monotherapy for patients with advanced WDLPS and DDLPS is disappointing. While palbociclib may have been used to delay surgery, there was no clear benefit from treatment and few patients achieved prolonged tumor control.

Giant retroperitoneal well-differentiated liposarcoma presenting in emergency with intestinal occlusion: Case report and review of the literature

INTRODUCTION AND IMPORTANCE

Liposarcoma (LPS) represents the most common type of retroperitoneal sarcoma (RPS) and can be classified into four subtypes. Preoperative diagnosis of retroperitoneal liposarcoma (RLPS) is a challenge because of its late and nonspecific clinical presentation. Imaging may be helpful for determining the correct diagnosis. Surgery represents a potentially curative treatment of RLPS.

CASE PRESENTATION

A 55-year-old Caucasian female presented to the Emergency Department with a two-day history of abdominal pain, abdominal distension, inability to pass gas or stool, nausea, vomiting and lipothymia. Abdominal examination revealed abdominal distention, abdominal pain without obvious muscle guarding and a giant non-tender mass. Laboratory tests reported neutrophilic leukocytosis and anemia. Abdominal contrast-enhanced computed tomography (CECT) showed a heterogeneous and hypodense giant retroperitoneal mass compressing and displacing the surrounding organs and vessels. The patient underwent excision of a giant retroperitoneal mass. The postoperative course of the patient was uneventful.

CLINICAL DISCUSSION

RLPS is a malignant neoplasm that can slowly grow to enormous size with possible involvement of adjacent organs and vessels; it may recur locally and has a minimal capacity to metastasize. Preoperative diagnosis and staging of RLPS are important to establish appropriate management and prognosis. Surgery represents the gold standard for non-metastatic RLPS treatment.

CONCLUSION

RLPS is a rare malignant neoplasm generally difficult to detect early due to its late and nonspecific clinical presentation. CECT represents the most commonly used modality for diagnosis, staging and preoperative evaluation. Surgery represents the appropriate treatment of non-metastatic RLPS.

Telomere as a Therapeutic Target in Dedifferentiated Liposarcoma

BACKGROUND

Well-differentiated (WD)/dedifferentiated (DD) liposarcoma (LPS) accounts for ~60% of retroperitoneal sarcomas. WDLPS and DDLPS divergently evolve from a common precursor and are both marked by the amplification of the 12q13-q15 region, leading to the abnormal expression of MDM2, CDK4, and HMGA2 genes. DDLPS is a non-lipogenic disease associated with aggressive clinical behavior. Patients have limited therapeutic options, especially for advanced disease, and their outcome remains largely unsatisfactory. This evidence underlines the need for identifying and validating DDLPS-specific actionable targets to design novel biology-driven therapies.

METHODS

Following gene expression profiling of DDLPS clinical specimens, we observed the up-regulation of "telomere maintenance" (TMM) pathways in paired DD and WD components of DDLPS. Considering the relevance of TMM for LPS onset and progression, the activity of a telomeric G-quadruplex binder (RHPS4) was assessed in DDLPS patient-derived cell lines.

RESULTS

Equitoxic concentrations of RHPS4 in DDLPS cells altered telomeric c-circle levels, induced DNA damage, and resulted in the accumulation of γ-H2AX-stained micronuclei. This evidence was paralleled by an RHPS4-mediated reduction of in vitro cell migration and induction of apoptosis/autophagy.

CONCLUSIONS

Our findings support telomere as an intriguing therapeutic target in DDLPS and suggest G-quadruplex binders as innovative therapeutic agents.

First-line chemotherapy in advanced intrabdominal well-differentiated/dedifferentiated liposarcoma: An EORTC Soft Tissue and Bone Sarcoma Group retrospective analysis

BACKGROUND

No prospective trial with anthracycline-based chemotherapy has individually assessed response in a well-differentiated (WD)/dedifferentiated (DD) liposarcoma patient cohort. We conducted a retrospective analysis of first-line chemotherapy in liposarcoma of intra-abdominal origin (IA-LPS) in patients who had entered the European Organisation for Research and Treatment of Cancer (EORTC)/Soft Tissue and Bone Sarcoma Group (STBSG) trials.

METHODS

We searched for all adult patients treated with first-line chemotherapy for advanced IA-LPS in the EORTC STBSG phase 2 and 3 trials from 1978. Treatment was aggregated into 5 groups: anthracycline alone, ifosfamide alone, doxorubicin plus ifosfamide (D+IFO), doxorubicin/cyclophosphamide/vincristine/dacarbazine, and "other" (brostallicin, trabectedin). Response was assessed prospectively by Response Evaluation Criteria in Solid Tumors or World Health Organization criteria. Progression-free survival (PFS) and overall survival (OS) were computed by Kaplan-Meier method.

RESULTS

A total of 109 patients with IA-LPS from 13 trials were identified (104 evaluable for response). Overall, there were 10/109 (9.2%) responders: 3/48 (6.3%) in the anthracycline alone group, 2/15 (13%) in the ifosfamide alone group, and 4/18 (22%) in the D+IFO group. At the 10-month median follow-up (interquartile range, 6-24), the median OS was 19 months (95% CI, 15-21) and median PFS 4 months (95% CI, 3-6). D+IFO achieved a not statistically significant longer median PFS (12 months) and median OS (31 months) than observed with other regimens. Univariate/multivariate analysis did not identify prognostic factors.

CONCLUSIONS

Cytotoxic chemotherapy, in particular anthracycline alone, had marginal activity in advanced IA-LPS. Ifosfamide-containing regimens showed higher activity, although it was not statistically significant and in a small number of cases, with the combination of doxorubicin and ifosfamide appearing to be the more active regimen available in fit patients. This series provides a benchmark for future trials on new drugs in WD/DD liposarcoma.

Antioxidant and Cytotoxic Activities of Kudzu Roots and Soy Molasses against Pediatric Tumors and Phytochemical Analysis of Isoflavones Using HPLC-DAD-ESI-HRMS

Pediatric solid tumors (PSTs) are life-threatening and can lead to high morbidity and mortality rates in children. Developing novel remedies to treat these tumors, such as glioblastoma multiforme and sarcomas, such as osteosarcoma, and rhabdomyosarcoma, is challenging, despite immense attempts with chemotherapeutic or radiotherapeutic interventions. Soy (Glycine max) and kudzu roots (KR) (Pueraria spp.) are well-known phytoestrogenic botanical sources that contain high amounts of naturally occurring isoflavones. In the present study, we investigated the antioxidant and cytotoxic effects of the extracts of KR and soy molasses (SM) against PSTs. The green extraction of isoflavones from KR and SM was performed using natural deep eutectic solvents. The extracts were subsequently analyzed by high-performance liquid chromatography (HPLC)-diode array detector (DAD) coupled with high-resolution (HR) mass spectrometry (MS), which identified 10 isoflavones in KR extracts and 3 isoflavones in the SM extracts. Antioxidant and cytotoxic activities of KR and SM extracts were assessed against glioblastoma multiforme (A-172), osteosarcoma (HOS), and rhabdomyosarcoma (Rd) cancer cell lines. The KR and SM extracts showed satisfactory cytotoxic effects (IC₅₀) against the cancer cell lines tested, particularly against Rd cancer cell lines, in a dose-dependent manner. Antioxidant activity was found to be significantly (p ≤ 0.05) higher in KR than in SM, which was consistent with the results of the cytotoxic activity observed with KR and SM extracts against glioblastoma and osteosarcoma cells. The total flavonoid content and antioxidant activities of the extracts were remarkably attributed to the isoflavone content in the KR and SM extracts. This study provides experimental evidence that HPLC-ESI-HRMS is a suitable analytical approach to identify isoflavones that exhibit potent antioxidant and anticancer potential against tumor cells, and that KR and SM, containing many isoflavones, can be a potential alternative for health care in the food and pharmaceutical industries.

Overview of systemic therapy options in liposarcoma, with a focus on the activity of selinexor, a selective inhibitor of nuclear export in dedifferentiated liposarcoma

Liposarcoma (LPS) is a common soft tissue sarcoma that encompasses diverse subtypes of well-differentiated/dedifferentiated, myxoid/round cell, and pleomorphic LPS. There is heterogeneity among the various LPS types with regard to prognosis, molecular pathogenesis, and response to treatment. Well-differentiated (WDLPS) and dedifferentiated liposarcoma (DDLPS) are most common types, which share common genetic alteration of chromosome 12q13-15 amplification resulting in amplification of oncogenes, including MDM2 (Mouse double minute 2), CDK4 (cyclin-dependent kinase 4), and HMGA2 (High mobility group protein AT-hook 2). Despite sharing the same molecular alteration, DDLPS has a worse prognosis, with a higher recurrence rate and higher propensity for metastases compared to WDLPS. Here we provide an overview of the LPS treatment landscape focusing on recent developments in the treatment of DDLPS with a focus on selinexor. Selinexor, a selective inhibitor of XPO1, was recently evaluated in a phase 3 trial, the first prospective randomized trial in DDLPS, and we discuss its efficacy in context of other available agents for DDLPS.

Case report: Two cases of primary paratesticular liposarcoma

Paratesticular liposarcoma is a sporadic urological tumor. We report the clinical presentation, treatment course, and prognosis of 2 cases of primary paratesticular liposarcoma with different pathological types, with the aim of further understanding the diagnosis and treatment of this rare disease. Case 1 was a 53-years-old male patient who presented with left scrotal enlargement with swelling 3 years ago and was considered to have a testicular malignancy on preoperative CT scan and enhanced MRI. The patient underwent resection of the left scrotal mass and left orchiectomy under general anaesthesia. Histopathological study confirmed the diagnosis of dedifferentiated liposarcoma. At the 4-months follow-up, no local recurrence or distant metastasis was observed. Case 2 is a 42-years-old male patient with a left scrotal mass which was discovered six months ago. Preoperatively, he underwent CT plain and enhanced MRI examinations suggesting an intra-scrotal occupancy. The patient underwent scrotoscopic excision of the left scrotal mass under general anesthesia. Histopathological studies confirmed the diagnosis of highly differentiated liposarcoma. At the 10-months follow-up, no local recurrence or distant metastasis was observed. Preoperative differential diagnosis of paratesticular liposarcoma should be noted with testicular tumor and extra-abdominal hernia. Extensive local excision and, if necessary, concomitant radical testicular resection is the treatment of choice. If the tumor in the scrotum spreads to the inguinal region, surgical removal with the aid of a scrotoscope may be attempted. This procedure avoids the formation of a large incision in the inguinal region compared to traditional open surgery. Patients commonly experience local recurrence and less distant metastases after surgery, so long-term follow-up is recommended.

Co-Targeting of MDM2 and CDK4/6 with Siremadlin and Ribociclib for the Treatment of Patients with Well-Differentiated or Dedifferentiated Liposarcoma: Results From a Proof-of-Concept, Phase Ib Study

PURPOSE

Well-differentiated (WDLPS) and dedifferentiated (DDLPS) liposarcoma are characterized by co-amplification of the murine double minute-2 (MDM2) and cyclin-dependent kinase-4 (CDK4) oncogenes. Siremadlin, a p53-MDM2 inhibitor, was combined with ribociclib, a CDK4/6 inhibitor, in patients with locally advanced/metastatic WDLPS or DDLPS who had radiologically progressed on, or despite, prior systemic therapy.

METHODS

In this proof-of-concept, phase Ib, dose-escalation study, patients received siremadlin and ribociclib across different regimens until unacceptable toxicity, disease progression, and/or treatment discontinuation: Regimen A (4-week cycle: siremadlin once daily [QD] and ribociclib QD, [2 weeks on, 2 weeks off]); Regimen B (3-week cycle: siremadlin once every 3 weeks; ribociclib QD [2 weeks on, 1 week off]); Regimen C (4-week cycle: siremadlin once every 4 weeks; ribociclib QD [2 weeks on, 2 weeks off]). The primary objective was to determine the maximum tolerated dose and/or recommended dose for expansion (RDE) of siremadlin plus ribociclib in one or more regimens.

RESULTS

As of 16 October 2019 (last patient last visit), 74 patients had enrolled. Median duration of exposure was 13 (range, 1-174) weeks. Dose-limiting toxicities occurred in 10 patients, most of which were Grade 3/4 hematologic events. The RDE was siremadlin 120 mg every 3 weeks plus ribociclib 200 mg QD (Regimen B). Three patients achieved a partial response, and 38 achieved stable disease. One patient (Regimen C) died as a result of treatment-related hematotoxicity.

CONCLUSION

Siremadlin plus ribociclib demonstrated manageable toxicity and early signs of antitumor activity in patients with advanced WDLPS or DDLPS.

Improving Immunotherapy Efficacy in Soft-Tissue Sarcomas: A Biomarker Driven and Histotype Tailored Review

Anti-PD-(L)1 therapies yield a disappointing response rate of 15% across soft-tissue sarcomas, even if some subtypes benefit more than others. The proportions of TAMs and TILs in their tumor microenvironment are variable, and this heterogeneity correlates to histotype. Tumors with a richer CD8+ T cell, M1 macrophage, and CD20+ cells infiltrate have a better prognosis than those infiltrated by M0/M2 macrophages and a high immune checkpoint protein expression. PD-L1 and CD8+ infiltrate seem correlated to response to immune checkpoint inhibitors (ICI), but tertiary lymphoid structures have the best predictive value and have been validated prospectively. Trials for combination therapies are ongoing and focus on the association of ICI with chemotherapy, achieving encouraging results especially with pembrolizumab and doxorubicin at an early stage, or ICI with antiangiogenics. A synergy with oncolytic viruses is seen and intratumoral talimogene laherpavec yields an impressive 35% ORR when associated to pembrolizumab. Adoptive cellular therapies are also of great interest in tumors with a high expression of cancer-testis antigens (CTA), such as synovial sarcomas or myxoid round cell liposarcomas with an ORR ranging from 20 to 50%. It seems crucial to adapt the design of clinical trials to histology. Leiomyosarcomas are characterized by complex genomics but are poorly infiltrated by immune cells and do not benefit from ICI. They should be tested with PIK3CA/AKT inhibition, IDO blockade, or treatments aiming at increasing antigenicity (radiotherapy, PARP inhibitors). DDLPS are more infiltrated and have higher PD-L1 expression, but responses to ICI remain variable across clinical studies. Combinations with MDM2 antagonists or CDK4/6 inhibitors may improve responses for DDLPS. UPS harbor the highest copy number alterations (CNA) and mutation rates, with a rich immune infiltrate containing TLS. They have a promising 15-40% ORR to ICI. Trials for ICB should focus on immune-high UPS. Association of ICI with FGFR inhibitors warrants further exploration in the immune-low group of UPS. Finally translocation-related sarcomas are heterogeneous, and although synovial sarcomas a poorly infiltrated and have a poor response rate to ICI, ASPS largely benefit from ICB monotherapy or its association with antiangiogenics agents. Targeting specific neoantigens through vaccine or adoptive cellular therapies is probably the most promising approach in synovial sarcomas.

Targeting abundant survivin expression in liposarcoma: subtype dependent therapy responses to YM155 treatment

Purpose

Liposarcoma (LPS) represent the largest group of malignant soft tissue tumours comprising a heterogeneous group of subtypes in which the degrees of chemoresistance and radiosensitivity strongly vary. Consequently, it is of utmost interest to establish novel therapeutic regimens based on molecular targets.

Methods

Immunohistochemical staining of survivin was performed in tissue microarrays comprising 49 primary LPS specimens. LPS cell lines were treated with survivin antagonist YM155 and doxorubicin or etoposide alone as well as in combination. Changes in cell viability were investigated and the synergistic effect of a combined therapy analysed.

Results

Immunohistochemistry revealed an abundant expression of survivin in LPS that significantly concurred with less-differentiated tumour subtypes and grading. In vitro, we demonstrated the impact of the survivin inhibitor YM155 on dedifferentiated LPS (DDLPS) and, even more imposing, pleomorphic LPS (PLS) tumour cell viability with a strong induction of apoptosis. A combined treatment of doxorubicin or etoposide with YM155 augmented the cytotoxic effects on DDLPS and PLS cells.

Conclusion

These findings support the significant role of survivin in the oncogenesis and progression of LPS subtypes providing a rationale to target survivin in eligible in-vivo models and to pioneer clinical applications of survivin-specific substances unfolding their therapeutic potential in LPS patients prospectively.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00432-021-03871-5.

[Active surgical approach for retroperitoneal liposarcoma]

OBJECTIVE

To assess the influence of active surgical approach on the long-term postoperative outcomes in patients with retroperitoneal liposarcoma.

MATERIAL AND METHODS

A retrospective study included 190 patients with retroperitoneal liposarcoma. The effect of malignancy grade, adjuvant chemotherapy, number of separate tumor nodes in primary neoplasm and the first relapse, as well as the number of previous total resections on survival rate was analyzed.

RESULTS

Overall and relapse-free survival is significantly worse in patients with high-grade retroperitoneal liposarcoma (G2-3) compared to low-grade (G1) tumor (p_log-rank=0.000). Multifocal growth of primary tumor (p=0.869; p_log-rank=0.607) and multiple (>1) separately located nodes in abdominal cavity and retroperitoneal space at the first relapse (p_log-rank=0.158 to 0.985) did not significantly impair prognosis after total resection of all types of retroperitoneal liposarcoma regardless malignancy grade. Adjuvant chemotherapy does not significantly improve relapse-free survival. Overall survival was significantly higher in patients who underwent ≥4 previous total resections compared to 1 surgical treatment for all types of retroperitoneal liposarcoma regardless malignancy grade (p=0.000; p_log-rank=0.001).

CONCLUSION

The only potentially radical treatment for patients with retroperitoneal liposarcoma is surgery. We reported the advantages of active surgical approach for improvement of long-term outcomes in patients with retroperitoneal liposarcoma.

Biology and Management of Dedifferentiated Liposarcoma: State of the Art and Perspectives

Dedifferentiated liposarcoma (DDL) is defined as the transition from well-differentiated liposarcoma (WDL)/atypical lipomatous tumor (ALT) to non-lipogenic sarcoma, which arises mostly in the retroperitoneum and deep soft tissue of proximal extremities. It is characterized by a supernumerary ring and giant marker chromosomes, both of which contain amplified sequences of 12q13-15 including murinedouble minute 2 (MDM2) and cyclin-dependent kinase 4 (CDK4) cell cycle oncogenes. Detection of MDM2 (and/or CDK4) amplification serves to distinguish DDL from other undifferentiated sarcomas. Recently, CTDSP1/2-DNM3OS fusion genes have been identified in a subset of DDL. However, the genetic events associated with dedifferentiation of WDL/ALT remain to be clarified. The standard treatment for localized DDL is surgery, with or without radiotherapy. In advanced disease, the standard first-line therapy is an anthracycline-based regimen, with either single-agent anthracycline or anthracycline in combination with the alkylating agent ifosfamide. Unfortunately, this regimen has not necessarily led to a satisfactory clinical outcome. Recent advances in the understanding of the pathogenesis of DDL may allow for the development of more-effective innovative therapeutic strategies. This review provides an overview of the current knowledge on the clinical presentation, pathogenesis, histopathology and treatment of DDL.

Histologic Subtype Defines the Risk and Kinetics of Recurrence and Death for Primary Extremity/Truncal Liposarcoma

OBJECTIVE

We sought to define the prognostic significance of histologic subtype for extremity/truncal liposarcoma (LPS).

BACKGROUND

LPS, the most common sarcoma, is comprised of 5 histologic subtypes. Despite their distinct behaviors, LPS outcomes are frequently reported as a single entity.

METHODS

We analyzed data on all patients from a single-institution prospective database treated from July 1982 to September 2017 for primary, nonmetastatic, extremity or truncal LPS of known subtype. Clinicopathologic variables were tested using competing risk analyses for association with disease-specific death (DSD), distant recurrence (DR), and local recurrence (LR).

RESULTS

Among 1001 patients, median follow-up in survivors was 5.4 years. Tumor size and subtype were independently associated with DSD and DR. Size, subtype, and R1 resection were independently associated with LR. DR was most frequent among pleomorphic and round cell LPS; the former recurred early (43% by 3 years), and the latter over a longer period (23%, 3 years; 37%, 10 years). LR was most common in dedifferentiated LPS, in which it occurred early (24%, 3 years; 33%, 5 years), followed by pleomorphic LPS (18%, 3 years; 25%, 10 years).

CONCLUSIONS

Histologic subtype is the factor most strongly associated with DSD, DR, and LR in extremity/truncal LPS. Both risk and timing of adverse outcomes vary by subtype. These data may guide selective use of systemic therapy for patients with round cell and pleomorphic LPS, which carry a high risk of DR, and radiotherapy for LPS subtypes at high risk of LR when treated with surgery alone.

Pharmacotherapy for liposarcoma: current and emerging synthetic treatments

Liposarcomas are rare tumors arising from adipocytic tissue and accounting for approximately 15-20% of all soft tissue sarcomas. Liposarcoma can be further classified into histopathological subtypes with variable chemosensitivity according to subtype. Decisions regarding management should be made on an individual basis, but surgery for localized disease and systemic chemotherapy remain the mainstay of treatment. Currently, only doxorubicin and trabectedin have robust Phase III data to support their use in the management of advanced liposarcoma. However, in the subgroup analysis of a Phase III trial comparing eribulin with dacarbazine, there was a greater than 7-month improvement in median overall survival in those treated with eribulin. There are also promising results from emerging studies in novel and targeted agents for the treatment of liposarcoma.

Impact of Pathological Stratification on the Clinical Outcomes of Advanced Well-Differentiated/Dedifferentiated Liposarcoma Treated with Trabectedin

BACKGROUND

We previously showed that grading can prognosticate the outcome of retroperitoneal liposarcoma (LPS). In the present study, we aimed to explore the impact of pathological stratification using grading on the clinical outcomes of patients with advanced well-differentiated LPS (WDLPS) and dedifferentiated LPS (DDLPS) treated with trabectedin.

PATIENTS

We included patients with advanced WDLPS and DDLPS treated with trabectedin at the Fondazione IRCCS Istituto Nazionale dei Tumori between April 2003 and November 2019. Tumors were categorized in WDLPS, low-grade DDLPS, and high-grade DDLPS according to the 2020 WHO classification. Patients were divided in two cohorts: Low-grade (WDLPS/low-grade DDLPS) and high-grade (high-grade DDLPS).

RESULTS

A total of 49 patients were included: 17 (35%) in the low-grade cohort and 32 (65%) in the high-grade cohort. Response rate was 47% in the low-grade cohort versus 9.4% in the high-grade cohort (logistic regression p = 0.006). Median progression-free survival (PFS) was 13.7 months in the low-grade cohort and 3.2 months in the high-grade cohort. Grading was confirmed as an independent predictor of PFS in the Cox proportional-hazards regression multivariable model (adjusted hazard ratio low-grade vs. high-grade: 0.45, 95% confidence interval: 0.22-0.94; adjusted p = 0.035).

CONCLUSIONS

In this retrospective case series, sensitivity to trabectedin was higher in WDLPS/low-grade DDLPS than in high-grade DDLPS. If confirmed in larger series, grading could represent an effective tool to personalize the treatment with trabectedin in patients with advanced LPS.

Selinexor versus doxorubicin in dedifferentiated liposarcoma PDXs: evidence of greater activity and apoptotic response dependent on p53 nuclear accumulation and survivin down-regulation

BACKGROUND

Dedifferentiated liposarcoma (DDLPS), a tumor that lacks effective treatment strategies and is associated with poor outcomes, expresses amplified MDM2 in the presence of wild-type p53. MDM2 ubiquitination of p53 facilitates its XPO1-mediated nuclear export, thus limiting p53 tumor suppressor functions. Consequently, nuclear export is a rational target in DDLPS. We directly compared the antitumor activity of the first-in class XPO1 inhibitor selinexor and doxorubicin, the standard front-line therapy in sarcomas, in DDLPS patient-derived xenografts (PDXs) and primary cell lines.

METHODS

Drug activity was assessed in three PDXs (and two corresponding cell lines) established from the dedifferentiated component of primary untreated retroperitoneal DDLPS with myogenic (N = 2) and rhabdomyoblastic (N = 1) differentiation from patients who underwent surgery. These models were marked by amplification of MDM2, CDK4 and HMGA2 genes.

RESULTS

Selinexor was moderately active in the three PDXs but achieved greater tumor response compared to doxorubicin (maximum tumor volume inhibition: 46-80 % vs. 37-60 %). The PDX harboring rhabdomyoblastic dedifferentiation showed the highest sensitivity to both agents. PDX response to selinexor and doxorubicin was not associated with the extent of MDM2 and CDK4 gene amplification. Interestingly, the most chemosensitive PDX model showed the lowest extent of HMGA2 amplification. Selinexor was also more efficient than doxorubicinin in inducing an apoptotic response in PDXs and cell lines. Consistently, an increased nuclear accumulation of p53 was seen in all selinexor-treated models. In addition, a time-dependent decrease of survivin expression, with an almost complete abrogation of the cytoplasmic anti-apoptotic pool of this protein, was observed as a consequence of the decreased acetylation/activation of STAT3 and the increased ubiquitination of nuclear survivin.

CONCLUSIONS

Selinexor showed a moderate antitumor activity in three DDLPS PDXs, which was, however, consistently higher than doxorubicin across all different models regardless the extent of MDM2 amplification and the histological differentiation. The depletion of survivin protein seems to significantly contribute to the induction of apoptosis through which selinexor exerts its antitumor activity.

The MDM2 inducible promoter folds into four-tetrad antiparallel G-quadruplexes targetable to fight malignant liposarcoma

Well-differentiated liposarcoma (WDLPS) is a malignant neoplasia hard to diagnose and treat. Its main molecular signature is amplification of the MDM2-containing genomic region. The MDM2 oncogene is the master regulator of p53: its overexpression enhances p53 degradation and inhibits apoptosis, leading to the tumoral phenotype. Here, we show that the MDM2 inducible promoter G-rich region folds into stable G-quadruplexes both in vitro and in vivo and it is specifically recognized by cellular helicases. Cell treatment with G-quadruplex-ligands reduces MDM2 expression and p53 degradation, thus stimulating cancer cell cycle arrest and apoptosis. Structural characterization of the MDM2 G-quadruplex revealed an extraordinarily stable, unique four-tetrad antiparallel dynamic conformation, amenable to selective targeting. These data indicate the feasibility of an out-of-the-box G-quadruplex-targeting approach to defeat WDLPS and all tumours where restoration of wild-type p53 is sought. They also point to G-quadruplex-dependent genomic instability as possible cause of MDM2 expansion and WDLPS tumorigenesis.

Paratesticular liposarcoma: Two case reports

BACKGROUND

Paratesticular liposarcoma accounts for approximately 7% of scrotal tumors. They are rare lesions of the reproductive system with approximately 90% of the lesions originating from the spermatic cord. Surgery, with the goal of complete resection, is the mainstay for treatment of this disease. However, treatment consisting of extended resection to decrease local recurrence remains controversial.

CASE SUMMARY

We report the cases of two patients with paratesticular liposarcomas who were treated with radical testicular tumor resection without adjuvant therapy. Follow-up investigations at 9 mo showed no sign of recurrence.

CONCLUSION

Surgery is the first-line treatment, regardless of whether it is a recurrent or primary tumor. Extended resection carries a higher risk of complications and should not be performed routinely. Preoperative radiotherapy can reduce the local recurrence rate without affecting the overall survival.

Efficacy and safety of anlotinib in patients with unresectable or metastatic well-differentiated/dedifferentiated liposarcoma: a single-center retrospective study

Treatment options for unresectable local recurrence or metastatic well-differentiated/dedifferentiated liposarcoma (WDLS/DDLS) remain limited. Different liposarcoma subtypes have varying clinical features and sensitivities to treatment regimens. The multitarget tyrosine kinase inhibitors (TKIs), such as pazopanib and regorafenib, have been approved for use in nonadipocytic soft tissue sarcomas (STS). Anlotinib, another TKI, has been approved in China for treating metastatic STS that has progressed after the use of anthracycline-based regimens. In this study, we aimed to evaluate the role of anlotinib in the treatment of local recurrence or metastatic WDLS/DDLS. From August 2018 to June 2020, 17 patients with unresectable local recurrence or metastatic WDLS/DDLS treated with anlotinib in our center were included. The follow-up cutoff time was set as 20 October 2020. Baseline and observation indicators were collected and analyzed. Estimated median progression-free survival (PFS) was 27.9 weeks, the PFS rate at 24 weeks was 58.8%, overall survival (OS) was 56.6 weeks, the disease control rate was 64.7% and no complete response or partial response was detected. Grade 3/4 adverse events occurred in four cases and could be managed. Anlotinib is a potential treatment option for unresectable local recurrence or metastatic WDLS/DDLS.

Treatment options in unresectable soft tissue and bone sarcoma of the extremities and pelvis - a systematic literature review

In patients with metastatic or unresectable soft tissue and bone sarcoma of extremities and pelvis, survival is generally poor. The aim of the current systematic review was to analyse recent publications on treatment approaches in patients with inoperable and/or metastatic sarcoma.

Original articles published between 1st January 2011 and 2nd May 2020, using the search terms ‘unresectable sarcoma’, ‘inoperability AND sarcoma’, ‘inoperab* AND sarcoma’, and ‘treatment AND unresectable AND sarcoma’ in PubMed, were potentially eligible. Out of the 839 initial articles (containing 274 duplicates) obtained and 23 further articles identified by cross-reference checking, 588 were screened, of which 447 articles were removed not meeting the inclusion criteria. A further 54 articles were excluded following full-text assessment, resulting in 87 articles finally being analysed.

Of the 87 articles, 38 were retrospective (43.7%), two prospective (2.3%), six phase I or I/II trials (6.9%), 22 phase II non-randomized trials (27.6%), nine phase II randomized trials (10.3%) and eight phase III randomized trials (9.2%). Besides radio/particle therapy, isolated limb perfusion and conventional chemotherapy, novel therapeutic approaches, including immune checkpoint inhibitors and tyrosine kinase inhibitors were also identified, with partially very promising effects in advanced sarcomas.

Management of inoperable, advanced or metastatic sarcomas of the pelvis and extremities remains challenging, with the optimal treatment to be defined individually. Besides conventional chemotherapy, some novel therapeutic approaches have promising effects in both bone and soft tissue subtypes. Considering that only a small proportion of studies were randomized, the clinical evidence currently remains moderate and thus calls for further large, randomized clinical trials.

Cite this article: EFORT Open Rev 2020;5:799-814. DOI: 10.1302/2058-5241.5.200069

Inflammatory Variant of Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma of the Buccal Mucosa: An Overview and Case Report with a 10-Year Follow-Up

Liposarcomas of the oral cavity are rare. Those originating in the buccal mucosa cause challenging diagnostic and therapeutic issues since less than 40 cases of liposarcomas of the buccal mucosa and cheek have been reported in the worldwide literature. Herein, we present a case of atypical lipomatous tumor/well-differentiated liposarcoma affecting a 45-year-old female patient. Ultrasonography and magnetic resonance imaging confirmed a well-defined mass located in the right buccal mucosa, extending to the submucosal layers of the cheek. Histopathologically, a well-differentiated fatty neoplasm with presence of prominent stromal inflammatory cells was observed. Multifocally scattered bizarre hyperchromatic stromal cells, some of which multinucleated, were also observed. An immunohistochemical panel comprising vimentin, S-100, CD10, CD34, CD20, CD3, CD68, CD138, MDM2, Ki-67, and P53 was employed to better characterize the lesion. A local recurrence event occurred during a 10-year follow-up period. Surgical resection was performed during both episodes. We also provided an overview of demographic and clinicopathological characteristics, immunohistochemical features, imaging findings, and the differential diagnosis of liposarcoma of the oral cavity. Knowledge of the etiopathological and clinical aspects of this rare neoplasm is fundamental in order to rule out other conditions, including lipomatous lesions that affect the buccal mucosa.

MDM2 Antagonists Induce a Paradoxical Activation of Erk1/2 through a P53-Dependent Mechanism in Dedifferentiated Liposarcomas: Implications for Combinatorial Strategies

The MDM2 gene is amplified in dedifferentiated liposarcoma (DDLPS). Treatment with MDM2 antagonists is a promising strategy to treat DDLPS; however, drug resistance is a major limitation when these drugs are used as a single agent. This study examined the impact of MDM2 antagonists on the mitogen-activated protein kinase (MAPK) pathway in DDLPS and investigated the potential synergistic activity of a MAPK kinase (MEK) inhibitor in combination with MDM2 antagonists. We identified a synergistic effect and identified the mechanism behind it. Combination effects of MDM2 antagonists and a MEK inhibitor were analyzed in a patient-derived xenograft mouse model and in DDLPS and leiomyosarcoma cell lines using different cell proliferation assays and immunoblot analysis. MDM2 antagonist (RG7388)-resistant IB115 [P4] cells and p53-silenced DDLPS cells were also established to understand the importance of functional p53. We found that MDM2 antagonists induced an upregulation of phosphorylated extracellular signal-regulated kinase (p-ERK) in DDLPS cells. The upregulation of p-ERK occurred due to mitochondrial translocation of p53, which resulted in increased production of reactive oxygen species, causing the activation of receptor tyrosine kinases (RTKs). Activated RTKs led to the activation of the downstream MEK/ERK signaling pathway. Treatment with a MEK inhibitor resulted in decreased expression of p-ERK, causing significant anti-tumor synergy when combined with MDM2 antagonists. Our results provide a framework for designing clinical studies of combination therapies in DDLPS patients.

PET/CT Imaging as a Diagnostic Tool in Distinguishing Well-Differentiated versus Dedifferentiated Liposarcoma

Distinguishing well-differentiated liposarcoma (WDLPS) from dedifferentiated liposarcoma (DDLPS) is essential given distinct treatment paradigms and chemosensitivity. Percutaneous biopsy has a low sensitivity for detecting DDLPS. We sought to identify the diagnostic utility of positron emission tomography/computed tomography (PET/CT) in identifying WDLPS versus DDLPS. An independent radiologist reviewed PET/CT images to identify target lesions and determine the maximum standardized uptake value (SUVmax). An independent pathologist review confirmed WDLPS or DDLPS histology. A binary cutoff point of SUVmax was identified using a classification and regression trees (CART) algorithm. We identified 20 patients with WDLPS or DDLPS with 26 PET/CTs performed for separate recurrences that were followed by surgical sampling. Of the 26 records, 12 were DDLPS (46%) and 14 were WDLPS (54%). Patients with DDLPS had significantly higher SUVmax than those with WDLPS (p value = 0.0035). A SUVmax of 4 was identified as the cutoff point. Using this cutoff, the sensitivity of SUVmax identifying a case as DDLPS was 83.3% (95% CI: 51.6%, 97.9%) and the specificity was 85.7% (95% CI: 57.2%, 98.2%). PET/CT is a sensitive and specific diagnostic tool to identify the presence of dedifferentiation within the tumor.

Accurate 3-gene-signature for early diagnosis of liposarcoma progression

Background

Well- and dedifferentiated liposarcoma (WD/DDLPS) are rare mesenchymal malignant tumors that account for 20% of all sarcomas in adults. The WD form is a low-grade malignancy with a favourable prognosis which may progress to DDLPS, a high-grade aggressive counterpart. WDLPS is referred to as atypical lipomatous tumour (ALT) when localised in extremities, due to its better prognosis. Currently the final differential diagnosis to distinguish between more aggressive and less aggressive form is based on post-surgical histological examination and no molecular biomarkers for early detection are available.

Methods

Quantitative polymerase chain reaction (qPCR) analysis of 11 metabolic genes involved in general and adipose tissue-specific metabolism, was performed on ALT (= 8), WDLPS (= 9) and DDLPS (= 20) samples. Subsequent statistical analysis was carried out to determine genes that most accurately can predict DDLPS differential diagnosis. Selected genes were further validated in a separate cohort by qPCR and the data statistically analysed. Deep sequencing was performed on DDLPS specimen from the metastatic patient and on five random WDLPS specimens.

Results

We established a three-gene signature based on PNPLA2, LIPE and PLIN1, which identified DDLPS with 100% sensitivity and 90% specificity, even in specimens from the WD component of DDLPS tumors. Interestingly, the PNPLA2 gene is deleted in 45% of DDLPS samples analyzed under TCGA project, and the deletion is associated with significantly lower PNPLA2 expression level. However, other mechanisms causing loss or downregulation of the expression of these three genes may be involved. Moreover, the significantly lower level of PNPLA2 is associated with R1 surgical margins, compare to R0 margins, which suggests the more invasive tumor phenotype in the absence of PNPLA2.

Conclusions

The identified metabolic signature allows highly accurate differential diagnosis between WD- and DDLPS even in samples containing lipid droplets, a marker of differentiation, which makes it very suitable for the use on biopsies. In respect to the pathogenesis of the disease, our results give a new insight into possible molecular mechanisms involved and support the recent observation that deletion of PNPLA2 is a novel factor in liposarcoma progression.