Prognostic significance of the MDM2/HMGA2 ratio and histological tumor grade in dedifferentiated liposarcoma

Exploring the Potential of Optical Genome Mapping in the Diagnosis and Prognosis of Soft Tissue and Bone Tumors

Sarcomas are rare malignant tumors of mesenchymal origin with a high misdiagnosis rate due to their heterogeneity and low incidence. Conventional diagnostic techniques, such as Fluorescence In Situ Hybridization (FISH) and Next-Generation Sequencing (NGS), have limitations in detecting structural variations (SVs), copy number variations (CNVs), and predicting clinical behavior. Optical genome mapping (OGM) provides high-resolution genome-wide analysis, improving sarcoma diagnosis and prognosis assessment. This study analyzed 53 sarcoma samples using OGM. Ultra-high molecular weight (UHMW) DNA was extracted from core and resection biopsies, and data acquisition was performed with the Bionano Saphyr platform. Bioinformatic pipelines identified structural variations, comparing them with known alterations for each sarcoma subtype. OGM successfully analyzed 62.3% of samples. Diagnostic-defining alterations were found in 95.2% of cases, refining diagnoses and revealing novel oncogenic and tumor suppressor gene alterations. The challenges included DNA extraction and quality issues from some tissue samples. Despite these limitations, OGM proved to be a powerful diagnostic and predictive tool for bone and soft tissue sarcomas, surpassing conventional methods in resolution and scope, enhancing the understanding of sarcoma genetics, and enabling better patient stratification and personalized therapies.

Giant dedifferentiated liposarcoma of the neck with osteosarcoma and chondrosarcoma components: A case report

Dedifferentiated liposarcoma (DDLPS) is a subtype of LPS characterized by two distinct levels of differentiation and morphological structures, comprising areas of well-differentiated LPS and dedifferentiated, non-lipogenic, highly malignant components. DDLPS most frequently occurs in the retroperitoneum and the soft tissues of the pelvis and limbs, and is rare in the head and neck region, accounting for only 1% of head and neck sarcomas. The present study describes the case of a 72-year-old male with a 30-year history of left upper limb numbness and heaviness. During physical examination, a tumor measuring ~13x22 cm was discovered in the left posterior region of the head and neck. The mass was hard in texture and had limited mobility. A biopsy of the lesion revealed a mesenchymal tumor rich in adipose components with ossification, containing heterologous elements primarily indicative of osteosarcoma, highly suggestive of DDLPS. A radical excision of the tumor was subsequently performed. The surgical specimen exhibits cross-sections with a gray-white to gray-yellow solid consistency, featuring gray-white, semi-transparent areas resembling cartilage. Immunohistochemical staining was positive for murine double minute 2 (MDM2), cyclin-dependent kinase 4 (CDK4), P16, P53, Vimentin and Ki-67, and negative for cytokeratin pan, S-100, CD34 and smooth muscle actin. Fluorescence in situ hybridization results indicated amplification of the MDM2 and CDK4 genes. In the present study, a case of a large DDLPS in the neck with components of osteosarcoma and chondrosarcoma was reported. There was no recurrence during the follow-up period. The pathological characteristics, diagnosis and current treatment methods for DDLPS were also described. Although cases of DDLPS have been reported, the number of cases described at this site remains limited to date, and it is currently not possible to accurately predict the treatment efficacy and prognosis.

Primary giant liposarcoma of the gallbladder: a case report and literature review

BACKGROUND

Liposarcoma of the gallbladder is an exceptionally rare malignancy originating from adipose tissue. Its rarity and diagnostic challenges make this case noteworthy. Liposa rcomas exhibit diverse histological subtypes, each with distinct biological behaviors, and there is limited consensus on optimal treatment approaches. This report emphasizes the importance of accurate diagnosis, effective therapeutic strategies, and detailed analysis of clinical outcomes in managing such rare cases.

CASE PRESENTATION

A 35-year-old woman presented with a two-month history of a palpable abdominal mass accompanied by mild bloating. She reported no significant discomfort, systemic symptoms, or changes in bowel habits. Imaging revealed a large abdominal mass displacing adjacent organs. Magnetic resonance imaging suggested a mixed-signal lesion originating from the gallbladder, and laboratory tests showed elevated inflammatory markers. The patient underwent successful surgical excision of the mass and cholecystectomy. Pathological examination confirmed a well-differentiated liposarcoma closely associated with the gallbladder. Immunohistochemistry indicated positivity for CDK4, MDM2, P16, S-100, and CD34, with a low proliferation index (Ki-67 ~ 10%). Postoperative recovery was uneventful, and the patient showed significant improvement. Long-term management, including genetic testing and follow-up, was planned to monitor recurrence risk and explore potential targeted therapies.

CONCLUSIONS

This case underscores the importance of considering rare malignancies like liposarcoma of the gallbladder in the differential diagnosis of abdominal masses. Early diagnosis through imaging and histopathological confirmation is crucial for optimal management. Complete surgical excision remains the cornerstone of treatment, particularly for well-differentiated subtypes, which generally have favorable prognoses. The findings highlight the need for multidisciplinary care and further research into genetic and molecular mechanisms to guide future targeted treatments.

Low-grade central osteosarcoma with extraosseous dedifferentiation: a rare case

Low-grade central osteosarcoma (LGCOS), which arises from the intramedullary cavity of the metaphysis of long bones, occasionally exhibits extraosseous spread. Approximately 10-30% of patients with LGCOS exhibit dedifferentiation, but it is rare to experience a primary tumor with a dedifferentiated component. A 38-year-old female patient presented with right knee pain for two months. Imaging studies revealed a bone mass with extraosseous involvement. Wide resection was performed, and pathologic examination led to the diagnosis of LGCOS with a dedifferentiated extraosseous lesion. A single defect in the bone cortex constituted the boundary between the low- and high-grade components. The extraosseous high-grade component included more tumor cells with p53 overexpression and more murine double minute 2 (MDM2) copies compared with the low-grade component. These genetic mutations and copy number alterations can be associated with malignant transformation of LGCOS.

Primary dedifferentiated liposarcoma of the gallbladder: a case report and literature review

Background

Liposarcoma (LPS) is a kind of malignancy of soft tissue usually found in the retroperitoneal, limb, or neck region, and some may be detected with delayed symptoms (pain or palpable mass), and less frequently occurs in organs of the digestive system. In contrast, Dedifferentiated liposarcoma (DDLPS) is a common histological subtype of LPS. The present study reported a case of dedifferentiated liposarcoma originating in the gallbladder. Differentiated liposarcoma originating from the gallbladder is rarely reported.

Case description

A 64-year-old female patient presented to our hospital with a painless abdominal mass. Abdominal computed tomography (CT) showed that the gallbladder had lost its normal shape, and a 9.1 cm × 7.1 cm × 12.1 cm mass was seen in the area of the gallbladder fossa and the right upper abdomen below it, which had an irregular morphology, inhomogeneous density, and nodular calcification, with marked inhomogeneous enhancement on enhancement scan. Preoperative tumor markers and liver function indicators were not abnormal. With suspicion of a giant malignant tumor of the gallbladder, she underwent a cholecystectomy combined with abdominal mass resection. After surgery, the tumor and gallbladder, were completely resected, and postoperative pathological results confirmed the diagnosis of dedifferentiated liposarcoma deriving from gallbladder. After surgery, the patient and his family refused to continue treatment. After 15 months follow-up, the patient remains asymptomatic and does not show any signs of recurrence. And she is now under continued follow - up.

Conclusions

Treatment of dedifferentiated liposarcoma is still at exploratory stage, and a lack of clinical evidence for this condition might hinder access to clinical trials and studies. Currently, the treatment of choice for dedifferentiated liposarcoma remains radical resection. In the available clinical studies, there are no robust data to support clinical use of neoadjuvant and adjuvant radiochemotherapy. As with other diseases, the use of radiotherapy and chemotherapy before and after surgery may be a potential future treatment.

Deciphering the prognostic and therapeutic significance of BAG1 and BAG2 for predicting distinct survival outcome and effects on liposarcoma

Liposarcoma (LPS) is the second most common kind of soft tissue sarcoma, and a heterogeneous malignant tumor derived from adipose tissue. Up to now, the prognostic value of BAG1 or BAG2 in LPS has not been defined yet. Expression profiling data of LPS patients were collected from TCGA and GEO database. Survival curves were plotted to verify the outcome differences of patients based on BAG1 or BAG2 expression. Univariate and multivariate Cox regression models were used to analyze the prognostic ability of BAG1 or BAG2. Chaperone's regulators BAG1 and BAG2 were identified as prognostic biomarkers for LPS patients, which exhibited distinct expression patterns and survival outcome prediction performances. Patients with high BAG2 expression and/or low BAG1 expression had worse prognosis. Enrichment analysis showed that BAG1 was involved in negative regulation of TGF-β signaling. Low expression of BAG1 was associated with high abundance of regulatory T cells (Tregs). The 2-gene signature model further confirmed the improved risk assessment performance of BAG1 and BAG2: high risk patients displayed poor prognosis. BAG1 and BAG2 are supposed to be potential prognostic biomarkers for LPS and have impacts on liposarcomagenesis and immune infiltration in distinctive manners, which may function as potential therapy targets (BAG1 agonists/BAG2 inhibitors) for LPS.

The association between CD34 expression status and the clinicopathological behavior of dedifferentiated liposarcoma

Lipogenic and fibrous tumors are thought to originate from CD34-positive stromal fibroblastic/fibrocystic cells. Well-differentiated lipogenic tumors typically express CD34, whereas dedifferentiated liposarcoma (DDLPS) often loses it. We conducted survival analyses involving 59 patients with DDLPS. Males comprised 53% of the cohort, and the median age at the time of wide resection of primary DDLPS was 60 years. Loss of CD34 expression was defined as when ≥50% of the dedifferentiated area was immunohistochemically negative for CD34. As a result, 39 of the 59 patients showed loss of CD34 expression during the initial operation for DDLPS. In the univariate analyses, the tumor site in the retroperitoneum/abdominal cavity and loss of CD34 expression were significantly associated with poor overall survival. In the multivariate analyses, loss of CD34 expression (HR = 2.26; 95% CI = 1.02-5.02; p = 0.04) and the tumor site in the retroperitoneum/abdominal cavity (HR = 3.11; 95% CI = 1.09-8.86; p = 0.03) were retained as independent prognostic factors. Six CD34-positive cases lost CD34 expression when they developed metastasis and/or local recurrence, suggesting that the loss was associated with the later stage of the tumor. Therefore, an association existed between the loss of CD34 expression and clinicopathological behaviors such as poorer prognoses and recurrence.

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.

Beyond targeting amplified MDM2 and CDK4 in well differentiated and dedifferentiated liposarcomas: From promise and clinical applications towards identification of progression drivers

Well differentiated and dedifferentiated liposarcomas (WDLPS and DDLPS) are tumors of the adipose tissue poorly responsive to conventional cytotoxic chemotherapy which currently remains the standard-of-care. The dismal prognosis of the DDLPS subtype indicates an urgent need to identify new therapeutic targets to improve the patient outcome. The amplification of the two driver genes MDM2 and CDK4, shared by WDLPD and DDLPS, has provided the rationale to explore targeting the encoded ubiquitin-protein ligase and cell cycle regulating kinase as a therapeutic approach. Investigation of the genomic landscape of WD/DDLPS and preclinical studies have revealed additional potential targets such as receptor tyrosine kinases, the cell cycle kinase Aurora A, and the nuclear exporter XPO1. While the therapeutic significance of these targets is being investigated in clinical trials, insights into the molecular characteristics associated with dedifferentiation and progression from WDLPS to DDLPS highlighted additional genetic alterations including fusion transcripts generated by chromosomal rearrangements potentially providing new druggable targets (e.g. NTRK, MAP2K6). Recent years have witnessed the increasing use of patient-derived cell and tumor xenograft models which offer valuable tools to accelerate drug repurposing and combination studies. Implementation of integrated "multi-omics" investigations applied to models recapitulating WD/DDLPS genetics, histologic differentiation and biology, will hopefully lead to a better understanding of molecular alterations driving liposarcomagenesis and DDLPS progression, as well as to the identification of new therapies tailored on tumor histology and molecular profile.

Dedifferentiated liposarcoma (DDLPS) in the rectum: A case report

Dedifferentiated liposarcoma (DDLPS) is a rare subtype of liposarcoma with a poor prognosis. This current case report describes a rectal DDLPS in a 68-year-old Chinese male that presented with lower abdominal pain and weight loss. Computed tomography and magnetic resonance imaging were undertaken to evaluate the tumour. The patient underwent radical resection of the rectal tumour, sigmoid colostomy and partial ureterectomy. The tumour was positive for mouse double minute 2 by immunohistochemistry. The patient healed well but refused chemotherapy postoperatively for economic reasons. The tumour recurred and metastasized 4 weeks after the operation. After relevant treatment, the patient's condition deteriorated and he died of shock, metabolic acidosis, hyperlactataemia and acute renal failure. The case report also reviews the literature in terms of the clinical diagnosis, treatment and pathological characteristics of rectal DDLPS with the aim of improving the level of diagnosis and treatment.

A Rare Case of Low-Grade Dedifferentiated Liposarcoma Presenting as a Pharyngeal Polyp: Avoiding a Pitfall With Significant Repercussions

Dedifferentiated liposarcoma is a nonlipogenic sarcoma of variable histological grade that frequently arises in association with a well-differentiated liposarcoma. Dedifferentiation occurs in approximately 10% of well-differentiated liposarcomas and is most commonly encountered in the retroperitoneum. Dedifferentiated liposarcoma of the upper respiratory tract is an extremely rare occurrence. Herein, we report a very rare case of low-grade dedifferentiated liposarcoma of the pharynx that presented as a polyp mimicking a benign process clinically and microscopically. We discuss the relevant molecular findings and review the current literature.

Clinicopathological and Histopathological Review of Dedifferentiated Liposarcoma: A Comprehensive Study of 123 Primary Tumours

AIMS

Dedifferentiated liposarcoma (DDLS) exhibits varying histopathological features, but their significance for the biological behaviour of this disease has not been fully clarified. This study aimed at elucidating the prognostic factors of DDLS by clinicopathologically reviewing a large case series.

METHODS AND RESULTS

We clinicopathologically reviewed 123 cases of primary de novo DDLS without preoperative treatment, including 81 in the internal trunk (internal DDLS) and 42 in peripheral sites (peripheral DDLS). Univariate and multivariate analyses of their features were also performed for all cases, the internal DDLS group, and the peripheral DDLS group. The results showed that, in all three groups, distant metastasis was significantly associated with shorter overall survival (OS) (univariate analysis, P<0.0001, =0.0011, and 0.0101, respectively), whereas local recurrence showed no significant effect on prognosis. Histopathologically, high mitotic count and the presence of round tumour cells were significantly associated with shorter OS in multivariate analysis of the internal DDLS group (P=0.0022, HR=4.39, 95% CI 1.71-11.28; P=0.0014, HR=7.19, 95% CI 2.14-24.16, respectively). Meanwhile, in the peripheral DDLS group, necrosis and high-grade histological components were significantly associated with shorter OS (univariate analysis, P=0.0068 and 0.0174, respectively).

CONCLUSIONS

The presence of round tumour cells may be one of the histological factors associated with a worse prognosis in DDLS, as previous studies indicated. This work also suggested that distant metastasis may be predictive of prognosis in both internal and peripheral DDLS, instead of local recurrence.

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

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

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.