A review of retroperitoneal liposarcoma genomics

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

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

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

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

A novel DDIT3 activator dehydroevodiamine effectively inhibits tumor growth and tumor cell stemness in pancreatic cancer

BACKGROUND

The existence of pancreatic cancer stem cells (PCSCs) results in limited survival benefits from current treatment options. There is a scarcity of effective agents for treating pancreatic cancer patients. Dehydroevodiamine (DeHE), a quinazoline alkaloid isolated from the traditional Chinese herb Evodiae fructus, exhibited potent inhibition of pancreatic ductal adenocarcinoma (PDAC) cell proliferation and tumor growth both in vitro and in vivo.

METHODS

The cytotoxic effect of DeHE on PDAC cells was assessed using CCK-8 and colony formation assays. The antitumor efficacy of DeHE were appraised in human PANC-1 xenograft mouse model. Sphere formation assay and flow cytometry were employed to quantify the tumor stemness. RNA-Seq analysis, drug affinity responsive target stability assay (DARTS), and RNA interference transfection were conducted to elucidate potential signaling pathways. Western blotting and immunohistochemistry were utilized to assess protein expression levels.

RESULTS

DeHE effectively inhibited PDAC cell proliferation and tumor growth in vitro and in vivo, and exhibited a better safety profile compared to the clinical drug gemcitabine (GEM). DeHE inhibited PCSCs, as evidenced by its suppression of self-renewal capabilities of PCSCs, reduced the proportion of ALDH+ cells and downregulated stemness-associated proteins (Nanog, Sox-2, and Oct-4) both in vitro and in vivo. Furthermore, there is potential involvement of DDIT3 and its downstream DDIT3/TRIB3/AKT/mTOR pathway in the suppression of stemness characteristics within DeHE-treated PDAC cells. Additionally, results from the DARTS assay indicated that DeHE interacts with DDIT3, safeguarding it against degradation mediated by pronase. Notably, the inhibitory capabilities of DeHE on PDAC cell proliferation and tumor stemness were partially restored by siDDIT3 or the AKT activator SC-79.

CONCLUSION

In summary, our study has identified DeHE, a novel antitumor natural product, as an activator of DDIT3 with the ability to suppress the AKT/mTOR pathway. This pathway is intricately linked to tumor cell proliferation and stemness characteristics in PDAC. These findings suggest that DeHE holds potential as a promising candidate for the development of innovative anticancer therapeutics.

Surgical resection due to poor outcome of the immunotherapy of a relapsed mediastinal liposarcoma: a case report

The feasibility of surgery after immunotherapy for mediastinal liposarcoma remains uncertain. Besides, the case of immunotherapy for liposarcoma is still lacking. We report a case of recurrence after resection of a left mediastinal liposarcoma. After recurrence, one course of pembrolizumab plus anlotinib hydrochloride showed no tumor shrinkage, and genetic testing showed CDK4 amplification and PD-L1 TPS <1%; therefore, the plan was changed to one course of pembrolizumab plus palbociclib, but the tumor still did not shrink. Thus, second tumor resection was performed. In addition, the postoperative pathology was still well-differentiated liposarcoma. The significance of immunotherapy in liposarcoma still needs to be further explored. In the absence of surgical contraindications, secondary surgery might be feasible.

Predictors and outcomes of recurrent retroperitoneal liposarcoma: new insights into its recurrence patterns

BACKGROUND

The clinical profiles of recurrent retroperitoneal liposarcoma (RLS) need to be explored. The recurrence patterns of RLS are controversial and ambiguous.

METHODS

A total of 138 patients with recurrent RLS were finally recruited in the study. The analysis of overall survival (OS) and recurrence-free survival (RFS) was performed by Kaplan‒Meier analysis. To identify independent prognostic factors, all significant variables on univariate Cox regression analysis (P ≤ 0.05) were subjected to multivariate Cox regression analysis. The corresponding nomogram model was further built to predict the survival status of patients.

RESULTS

Among patients, the 1-, 3-, and 5-year OS rates were 70.7%, 35.9% and 30.9%, respectively. The 1-, 3- and 5-year RFS rates of the 55 patients who underwent R0 resection were 76.1%, 50.8% and 34.4%, respectively. The multivariate analysis revealed that resection method, tumor size, status of pathological differentiation, pathological subtypes and recurrence pattern were independent risk factors for OS or RFS. Patients with distant recurrence (DR) pattern usually had multifocal tumors (90.5% vs. 74.7%, P < 0.05); they were prone to experience changes of pathological differentiation (69.9% vs. 33.3%, P < 0.05) and had a better prognosis than those with local recurrence (LR) pattern. R0 resection and combined organ resection favored the survival of patients with DR pattern in some cases.

CONCLUSIONS

Patients with DR pattern had better prognosis, and they may benefit more from aggressive combined resection than those with LR pattern. Classifying the recurrence patterns of RLS provides guidance for individualized clinical management of recurrent RLS.

Nomogram development and external validation for predicting overall survival and cancer-specific survival in patients with primary retroperitoneal sarcoma: a retrospective cohort study

BACKGROUND

Primary retroperitoneal sarcoma (RPS) comprises over 70 histologic subtypes, yet there are limited studies that have developed prognostic nomograms for RPS patients to predict overall survival (OS) and cancer-specific survival (CSS). The objective of this study was to construct prognostic nomograms for predicting OS and CSS in RPS patients.

METHODS

We identified a total of 1166 RPS patients from the Surveillance, Epidemiology and End Results (SEER) database, and an additional 261 cases were collected from a tertiary cancer center. The study incorporated various clinicopathological and epidemiologic features as variables, and prediction windows for overall survival (OS) and cancer-specific survival (CSS) were set at 3, 5, and 7 years. Multivariable Cox models were utilized to develop the nomograms, and variable selection was performed using a backward procedure based on the Akaike Information Criterion. To evaluate the performance of the nomograms in terms of calibration and discrimination, we used calibration plots, coherence index, and area under the curve.

FINDINGS

The study included 818 patients in the development cohort, 348 patients in the internal validation cohort, and 261 patients in the external validation cohort. The backward procedure selected the following variables: age, French Federation of Cancer Centers Sarcoma Group (FNCLCC) grade, pre-/postoperative chemotherapy, tumor size, primary site surgery, and tumor multifocality. The validation results demonstrated that the nomograms had good calibration and discrimination, with C-indices of 0.76 for OS and 0.81 for CSS. Calibration plots also showed good consistency between the predicted and actual survival rates. Furthermore, the areas under the time-dependent receiver operating characteristic curves for the 3-, 5-, and 7-year OS (0.84, 0.82, and 0.78, respectively) and CSS (0.88, 0.88, and 0.85, respectively) confirmed the accuracy of the nomograms.

INTERPRETATION

Our study developed accurate nomograms to predict OS and CSS in patients with RPS. These nomograms have important clinical implications and can assist healthcare providers in making informed decisions regarding patient care and treatment options. They may also aid in patient counseling and stratification in clinical trials.

Predictors and outcomes of recurrent retroperitoneal liposarcoma with multiple tumors

Background

Retroperitoneal liposarcoma (RLS) is a rare but severe disease. Repeated postoperative recurrence with multiple tumors is a therapeutic dilemma. The clinical outcomes and survival predictors of recurrent RLS with multiple tumors remain to be explored.

Methods

Patients with recurrent RLS were retrospectively analyzed. Univariate and multivariate analysis was performed to find independent prognostic factors that were correlated with Overall survival (OS) or progression-free survival (PFS). Factors significant in univariate analysis were further included into multivariate Cox proportional hazards regression model. The nomogram model was built to predict the survival status of patients. Variables that were significant in multivariable analysis were added to the internally validated nomogram models. The analysis of OS and PFS was performed by Kaplan-Meier analysis and log-rank test.

Results

A total of 113 recurrent RLS patients with multiple tumors were enrolled in the study. The 1-, 3-, and 5-years OS (PFS) rates were 70.7% (76.1%), 35.9% (76.1%), and 30.9% (76.1%), respectively. Univariate and multivariate analyses showed that number of surgeries, resection methods, tumor size, status of pathological differentiation, pathological subtypes, and recurrence patterns were important prognostic factors for OS or PFS (each p < 0.05). Nomogram models were established to efficiently predict the prognostic status of patients. Patients with the local recurrence (LR) pattern had a poor prognosis and would derive no survival benefit from combined organ resection and R0/R1 resection (each p < 0.05).

Conclusion

RLS patients recurrence with multiple tumors had a poor prognosis. Those patients should be followed up more frequently after surgery. The strategies of aggressive resection may not improve the survival of patients with LR pattern in the retroperitoneum. Prognostic factors in the efficient nomogram models should be considered in the individualized clinical management of recurrent RLS with multiple tumors.

Survival of a patient with five recurrences of retroperitoneal liposarcoma over a period of 13 years: A case report and review

Retroperitoneal liposarcoma (RPLS) is a rare tumor that occurs in the retroperitoneal region and accounts for ~0.2% of all malignant tumor incidence. The present study describes the treatment of a surviving patient with RPLS that recurred five times in 13 years. This case has a long survival time and numerous relapses, which is a rare occurrence. The 40-year-old female patient was admitted to Shaoxing Second Hospital (Shaoxing, China) with an abdominal mass. Abdominal computed tomography (CT) scan revealed multiple liposarcoma recurrences in the abdominal, pelvic and retroperitoneal areas. As the diagnosis of RPLS was the fifth recurrence, cytoreductive surgery was performed and post-operative pathology suggested mixed liposarcoma. The patient underwent six cycles of doxorubicin and ifosfamide regimen chemotherapy and targeted therapy with anlotinib following surgery; no evidence of disease progression was found on abdominal CT scan during follow-up. The present study also reviewed the literature in terms of the clinical diagnosis, treatment, pathological characteristics and similar cases of liposarcoma with the aim of improving diagnosis and treatment.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Transarterial Embolization and Percutaneous Ablation of Primary and Metastatic Soft Tissue Tumors

Soft tissue tumors (STTs) include a range of benign and malignant tumors originating from soft tissues. Transarterial and percutaneous therapies are image-guided and minimally invasive approaches for managing primary and metastatic STTs. The objective of this review is to discuss transarterial and percutaneous therapies by examining the current literature, including indications, patient selection, safety, and effectiveness. Transarterial therapies (e.g., transarterial bland embolization and transarterial chemoembolization) involve the delivery of either embolic or chemotherapeutic particles using a catheter into arteries feeding the tumor, resulting in localized tumor destruction. Percutaneous therapies (e.g., radiofrequency ablation, cryoablation, irreversible electroporation, laser ablation, and magnetic resonance-guided high-intensity focused ultrasound) involve the delivery of either hot or cold temperatures, electrical current, laser, or ultrasound to specifically target tumor cells. Both therapies have been shown to be safe and effective for reducing morbidity and local control of STTs, specifically in patients who are surgically inoperable or who are unresponsive to conventional therapies. Accurate diagnosis, staging, and histological subtype identification are crucial for treatment selection. A multidisciplinary approach, a thorough understanding of tissue anatomy and surrounding structures, as well as individualized strategies based on assessment are essential for optimal patient care.

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

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

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

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

Retroperitoneal liposarcoma and craniosynostosis: possible genomic relationship, case report, and literature review

Based on a case report, this review explores the genomic landscape for patients with liposarcomas and possible relationships with gene mutations related to craniosynostosis. We describe the case of a 40-year-old man, known for a surgical correction of craniosynostosis before the age of 1 year, who underwent a radical resection of a voluminous retroperitoneal liposarcoma; histopathological analysis revealed a low-grade well-differentiated, mostly sclerosing, liposarcoma. A genetic analysis searching for mutations in blood DNA was performed and did not detect any specific mutation. A literature review was also conducted. Several tumors related to syndromic and non-syndromic craniosynostosis are mentioned in the literature; no specific link with retroperitoneal liposarcoma is established but the FGFR3 mutation is detected in dedifferentiated liposarcomas. To date, no case has been reported in the literature demonstrating a genetic relationship between craniosynostosis and low-grade differentiated retroperitoneal liposarcoma. We conclude that further studies for gene complex mutations should be conducted to show a possible genetic relationship between retroperitoneal liposarcoma and craniosynostosis.

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.

Survival of a patient with multiple-recurrent giant retroperitoneal dedifferentiated liposarcoma for 15 years: A case report

Background

Retroperitoneal liposarcoma (RPLS) is a variety of soft tissue sarcoma that originates from mesenchymal cells. A tumor measuring greater than 30 cm is called a “giant liposarcoma.” A part of the neoplasm tends to grow in size, recur locally, or metastasize distantly. In those with such a condition, long-term survival is uncommon. Therefore, it is necessary to present a uniform and optimized program to improve the prognosis.

Methods

By successfully treating a multiple-recurrent giant retroperitoneal dedifferentiated liposarcoma (RP DDLPS) in July 2010, we hope to devise more comprehensive strategies to improve diagnosis, therapy, and outcome.

Results

In July 2010, we thoroughly resected a giant multifocal RPLS with a concomitant part of the gastric wall. The histopathological examination revealed a high-grade (grade III) dedifferentiated liposarcoma. The patient was discharged uneventfully on the 15th postoperative day. She relapsed after 16 months and needed another complete excision. After 9 months, she died after the fourth recidive. The patient had experienced four recurrences and underwent operations with 15 years of follow-up.

Conclusions

The above demonstrates that we were able to successfully treat the multirecurrent giant RPLS, despite the patient’s poor medical condition, with meticulous management. Moreover, this indicates that long-term survival could be achieved for high-grade RP DDLPS.

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.

The Immune Contexture of Liposarcoma and Its Clinical Implications

Liposarcomas (LPS) are the most frequent malignancies in the soft tissue sarcoma family and consist of five distinctive histological subtypes, termed well-differentiated LPS, dedifferentiated LPS (DDLPS), myxoid LPS (MLPS), pleomorphic LPS, and myxoid pleomorphic LPS. They display variations in genetic alterations, clinical behavior, and prognostic course. While accumulating evidence implicates a crucial role of the tumor immune contexture in shaping the response to anticancer treatments, the immunological landscape of LPS is highly variable across different subtypes. Thus, DDLPS is characterized by a higher abundance of infiltrating T cells, yet the opposite was reported for MLPS. Interestingly, a recent study indicated that the frequency of pre-existing T cells in soft tissue sarcomas has a predictive value for immune checkpoint inhibitor (CPI) therapy. Additionally, B cells and tertiary lymphoid structures were identified as potential biomarkers for the clinical outcome of LPS patients and response to CPI therapy. Furthermore, it was demonstrated that macrophages, predominantly of M2 polarization, are frequently associated with poor prognosis. An improved understanding of the complex LPS immune contexture enables the design and refinement of novel immunotherapeutic approaches. Here, we summarize recent studies focusing on the clinicopathological, genetic, and immunological determinants of LPS.

Updates in Pathology for Retroperitoneal Soft Tissue Sarcoma

Retroperitoneal tumors are extremely rare. More than 70% of primary retroperitoneal soft tissue tumors are malignant. The most common sarcomas in the retroperitoneum include liposarcomas and leiomyosarcoma, however other sarcomas, along with benign mesenchymal tumors, can occur. Sarcomas are a heterogenous group of tumors with overlapping microscopic features, posing a diagnostic challenge for the pathologist. Correct tumor classification has become important for prognostication and the evolving targeted therapies for sarcoma subtypes. In this review, the pathology of retroperitoneal soft tissue sarcomas is discussed, which is important to the surgical oncologist. In addition, less common sarcomas and benign mesenchymal tumors of the retroperitoneum, which may mimic sarcoma clinically and pathologically, are also discussed.

Effects of marital status on survival of retroperitoneal liposarcomas stratified by age and sex: A population-based study

BACKGROUND

Previous studies have shown that marital status is associated with survival in patients with a variety of cancer types, including lung cancer, prostate cancer, and bladder cancer. However, to date, the impact of marital status on the survival of patients with retroperitoneal liposarcomas (RPLs) has not been established.

METHODS

A total of 1211 eligible patients diagnosed with RPLs were identified in the Surveillance, Epidemiology, and End Results (SEER) database. The relationships between marital status and survival in patients with RPLs were assessed. Patients were stratified by age to determine whether an association exists between marital status and age. We also probed the association between marital status and survival in males and females.

RESULTS

Our findings suggest that divorced, separated, or widowed patients have more advanced cancer stages, and more of these patients do not undergo surgery. Meanwhile, divorced, separated, or widowed patients have worse survival outcomes than married patients (overall survival (OS): HR = 1.66 (95% CI, 1.12, 2.46)); cancer-specific survival (CSS): HR = 1.90 (95% CI, 1.13, 3.19)). OS does not differ between single patients and married patients (HR = 1.21 [95% CI, 0.81, 1.81]) or CSS (HR = 1.36 [95% CI, 0.80, 2.29]). In addition, these results demonstrate that being divorced, separated, or widowed can play a significant detrimental role in mortality in older and female patients.

CONCLUSION

Married patients have earlier disease stages at diagnosis and better survival outcomes than divorced, separated, or widowed patients with RPLs. In addition, this effect is especially pronounced in older people and females.

Development and Validation of a Prognostic Model to Predict the Prognosis of Patients With Retroperitoneal Liposarcoma: A Large International Population-Based Cohort Study

Background

Retroperitoneal liposarcomas (RPLs), sarcoma of mesenchymal origin, are the most common soft tissue sarcomas (STS) of the retroperitoneum. Given the rarity of RPLs, the prognostic values of clinicopathological features in the patients remain unclear. The nomogram can provide a visual interface to aid in calculating the predicted probability that a patient will achieve a particular clinical endpoint and communication with patients.

Methods

We included a total of 1,392 RPLs patients diagnosed between 2004 and 2015 from the Surveillance, Epidemiology, and End Results (SEER) database. For nomogram construction and validation, patients in the SEER database were divided randomly into the training cohort and internal validation cohort at a ratio of 7:3, while 65 patients with RPLs from our center between 2010 and 2016 served as the external validation cohort. The OS curves were drawn using the Kaplan–Meier method and assessed using the log-rank test. Moreover, Fine and Gray’s competing-risk regression models were conducted to assess CSS. Univariate and multivariate analyses were performed to select the prognostic factors for survival time. We constructed a predictive nomogram based on the results of the multivariate analyses.

Results

Through univariate and multivariate analyses, it is found that age, histological grade, classification, SEER stage, surgery constitute significant risk factors for OS, and age, classification, SEER stage, AJCC M stage, surgery, and tumor size constitute risk factors for CSS. We found that the nomogram provided a good assessment of OS and CSS at 1, 3, and 5 years in patients with RPLs (1-year OS: (training cohort: AUC = 0.755 (95% CI, 0.714, 0.796); internal validation cohort: AUC = 0.754 (95% CI, 0.681, 0.827); external validation cohort: AUC = 0.793 (95% CI, 0.651, 0.935)); 3-year OS: (training cohort: AUC = 0.782 (95% CI, 0.752, 0.811); internal validation cohort: AUC = 0.788 (95% CI, 0.736, 0.841); external validation cohort: AUC = 0.863 (95% CI, 0.773, 0.954)); 5-year OS: (training cohort: AUC = 0.780 (95% CI, 0.752, 0.808); internal validation cohort: AUC = 0.783 (95% CI, 0.732, 0.834); external validation cohort: AUC = 0.854 (95% CI, 0.762, 0.945)); 1-year CSS: (training cohort: AUC = 0.769 (95% CI, 0.717, 0.821); internal validation cohort: AUC = 0.753 (95% CI, 0.668, 0.838); external validation cohort: AUC = 0.799 (95% CI, 0.616, 0.981)); 3-year CSS: (training cohort: AUC = 0.777 (95% CI, 0.742, 0.811); internal validation cohort: AUC = 0.787 (95% CI, 0.726, 0.849); external validation cohort: AUC = 0.808 (95% CI, 0.673, 0.943)); 5-year CSS: (training cohort: AUC = 0.773 (95% CI, 0.741, 0.805); internal validation cohort: AUC = 0.768 (95% CI, 0.709, 0.827); external validation cohort: AUC = 0.829 (95% CI, 0.712, 0.945))). The calibration plots for the training, internal validation, and external validation cohorts at 1-, 3-, and 5-year OS and CSS indicated that the predicted survival rates closely correspond to the actual survival rates.

Conclusion

We constructed and externally validated an unprecedented nomogram prognostic model for patients with RPLs. The nomogram can be used as a potential, objective, and supplementary tool for clinicians to predict the prognosis of RPLs patients around the world.

Retroperitoneal Liposarcoma: An Unusual Presentation of a Rare Cancer

Retroperitoneal liposarcomas (RLPS) are rare tumors that have variable clinical behavior and complex treatment strategies based on presentation, histopathology, and genomics. Early identification is critical, and complete surgical resection remains the primary treatment, although chemotherapy and radiation are used on individual bases. Presenting symptoms are often nonspecific; therefore, a high degree of suspicion is essential for early diagnosis. In this report, the management of a 37-year-old otherwise healthy male with a large RLPS causing right groin/testicular pain is presented. After three evaluations in the emergency department, the patient was diagnosed and received two cycles of doxorubicin/ifosfamide/mesna (AIM) neoadjuvant chemotherapy. His physical exam on presentation for second opinion demonstrated a large palpable abdominal mass and fullness around the right spermatic cord. There was no appreciable change in tumor size or distant metastases on repeat scanning. Given some obstructive symptoms, a multidisciplinary team advised neoadjuvant radiation followed by radical resection of RLPS. Final pathology demonstrated a 31-cm grade II well-differentiated (WD) liposarcoma with low-grade dedifferentiation. Scattered foci of microscopic positive WD margins were noted, and the remainder of margins were negative. Genomic evaluation showed amplification of CDK4, MDM2, and FRS2. A concise literature review of common presentations, histopathology, genomics, and treatment information is discussed herein. Thorough physical exams, attention to subtle findings, appropriate medical imaging studies, and a high index of suspicion when evaluating vague symptomatology can lead to earlier diagnosis and treatment of RLPS, and ultimately better patient outcomes.

Targetable Pathways in the Treatment of Retroperitoneal Liposarcoma

Liposarcoma (LPS) is the most prevalent soft tissue sarcoma histological subtype. When it occurs in the abdomen the overall survival rate is as low as 10% at 10 years and is fraught with high rates of recurrence, particularly for the more aggressive dedifferentiated subtype. Surgery remains the mainstay of treatment. Systemic therapies for the treatment of metastatic or unresectable disease have low response rates. Deep understanding of well-differentiated and de-differentiated LPS (WDLPS and DDLPS, respectively) oncologic drivers is necessary for the development of new efficacious targeted therapies for the management of this disease. This review discusses the current treatments under evaluation for retroperitoneal DDLPS and the potential targetable pathways in DDLPS.

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.

Establishment and Characterization of NCC-DDLPS4-C1: A Novel Patient-Derived Cell Line of Dedifferentiated Liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly malignant sarcoma characterized by the co-amplification of MDM2 and CDK4. Although systemic chemotherapy is recommended for unresectable or metastatic cases, DDLPS is insensitive to conventional chemotherapy, leading to an unfavorable prognosis. Therefore, novel treatment methods are urgently required. Patient-derived cell lines are essential in preclinical studies. Recently, large-scale screening studies using a number of cell lines have been actively conducted for the development of new therapeutic drugs. However, the DDLPS cell line cannot be obtained from public cell banks owing to its rarity, hindering screening studies. As such, novel DDLPS cell lines need to be established. Accordingly, this study aimed to establish a novel DDLPS cell line from surgical specimens. The cell line was named NCC-DDLPS4-C1. NCC-DDLPS4-C1 cells retained copy number alterations corresponding to the original tumors. Further, the cells demonstrated constant growth, spheroid formation, and equivalent invasiveness to MG63 osteosarcoma cells. We also conducted drug screening and integrated the results with those of the previously reported DDLPS cell lines. Consequently, we identified the histone deacetylase inhibitor romidepsin as a novel candidate drug. In conclusion, the NCC-DDLPS4-C1 cell line is a useful tool for the basic study of DDLPS.

Targeted and immuno-based therapies in sarcoma: mechanisms and advances in clinical trials

Sarcomas represent a distinct group of rare malignant tumors with high heterogeneity. Limited options with clinical efficacy for the metastatic or local advanced sarcoma existed despite standard therapy. Recently, targeted therapy according to the molecular and genetic phenotype of individual sarcoma is a promising option. Among these drugs, anti-angiogenesis therapy achieved favorable efficacy in sarcomas. Inhibitors targeting cyclin-dependent kinase 4/6, poly-ADP-ribose polymerase, insulin-like growth factor-1 receptor, mTOR, NTRK, metabolisms, and epigenetic drugs are under clinical evaluation for sarcomas bearing the corresponding signals. Immunotherapy represents a promising and favorable method in advanced solid tumors. However, most sarcomas are immune "cold" tumors, with only alveolar soft part sarcoma and undifferentiated pleomorphic sarcoma respond to immune checkpoint inhibitors. Cellular therapies with TCR-engineered T cells, chimeric antigen receptor T cells, tumor infiltrating lymphocytes, and nature killer cells transfer show therapeutic potential. Identifying tumor-specific antigens and exploring immune modulation factors arguing the efficacy of these immunotherapies are the current challenges. This review focuses on the mechanisms, advances, and potential strategies of targeted and immune-based therapies in sarcomas.

Chaperonin-Containing TCP1 Complex (CCT) Promotes Breast Cancer Growth Through Correlations With Key Cell Cycle Regulators

Uncontrolled proliferation as a result of dysregulated cell cycling is one of the hallmarks of cancer. Therapeutically targeting pathways that control the cell cycle would improve patient outcomes. However, the development of drug resistance and a limited number of inhibitors that target multiple cell cycle modulators are challenges that impede stopping the deregulated growth that leads to malignancy. To advance the discovery of new druggable targets for cell cycle inhibition, we investigated the role of Chaperonin-Containing TCP1 (CCT or TRiC) in breast cancer cells. CCT, a type II chaperonin, is a multi-subunit protein-folding complex that interacts with many oncoproteins and mutant tumor suppressors. CCT subunits are highly expressed in a number of cancers, including breast cancer. We found that expression of one of the CCT subunits, CCT2, inversely correlates with breast cancer patient survival and is subject to copy number alterations through genomic amplification. To investigate a role for CCT2 in the regulation of the cell cycle, we expressed an exogenous CCT2-FLAG construct in T47D and MCF7 luminal A breast cancer cells and examined cell proliferation under conditions of two-dimensional (2D) monolayer and three-dimensional (3D) spheroid cultures. Exogenous CCT2 increased the proliferation of cancer cells, resulting in larger and multiple spheroids as compared to control cells. CCT2-expressing cells were also able to undergo spheroid growth reversal, re-attaching, and resuming growth in 2D cultures. Such cells gained anchorage-independent growth. CCT2 expression in cells correlated with increased expression of MYC, especially in spheroid cultures, and other cell cycle regulators like CCND1 and CDK2, indicative of a novel activity that could contribute to the increase in cell growth. Statistically significant correlations between CCT2, MYC, and CCND1 were shown. Since CCT2 is located on chromosome 12q15, an amplicon frequently found in soft tissue cancers as well as breast cancer, CCT2 may have the basic characteristics of an oncogene. Our findings suggest that CCT2 could be an essential driver of cell division that may be a node through which pathways involving MYC, cyclin D1 and other proliferative factors could converge. Hence the therapeutic inhibition of CCT2 may have the potential to achieve multi-target inhibition, overcoming the limitations associated with single agent inhibitors.

A single institutional experience treating adipocytic tumors: incidence, disease-related outcomes, and the clinical significance of MDM2 analysis

Adipocytic tumors exist either as a benign or malignant form. The benign variant, lipoma, is composed of normal fat tissue. Lipomas typically develop from superficial fat cells beneath the skin or mucous membranes. Liposarcoma, the malignant counterpart, often develops in deeper tissues and is the most commonly diagnosed Soft Tissue Sarcoma (STS), comprising at least 20% of adult STS. However, malignant tumors of fatty origin exist as a spectrum of diagnoses, each carrying a unique risk of recurrence, metastasis, and longterm survival. The World Health Organization classifies liposarcomas into five categories: i) Atypical Lipomatous Tumors/Well Differentiated (ALT/WD); Ii) Dedifferentiated (ALT/DD); Iii) Myxoid; Iv) Round cell; and v) Pleomorphic. Lipomatous tumors often exhibit different immunohistochemical patterns. Benign lipomas are distinguished by the absence of Murine Double-Minute 2 (MDM2) amplification. Similarly, ALT/WD, classically defined as a low-grade and locally aggressive tumor, demonstrates consistent patterns of MDM2 amplification. Some studies suggest 10% of ALT/WD progress to the highgrade DD form, with others report a dedifferentiation rate of as high as 20% for primary ALT/WD based on location. The ALT/DD subtype is aggressive and has a high capacity to metastasize. While the mechanism of pathogenesis of ALT/DD metastasis is unknown, previous studies suggest that increased MDM2 amplification may play a role. This study sought to evaluate a single institutional experience treating the entire spectrum of lipomatous tumors and describe utilization patterns of MDM2 testing. The group hypothesized: i) Atypical Lipomatous Tumors (ALT), which include ALT/DD and ALT/WD, would exhibit a higher rate of local recurrence than lipomas with no significantly increased incidence of metastases; and ii) at least 50% of our MDM2 testing of ALT would prove positive for the MDM2 overamplification. This study retrospectively reviewed 105 cases (66 lipomas, 27 ALTs, 12 liposarcomas) of patients who underwent lipomatous tumor excision at our institution from 2013 to 2017. Twenty-five tumors (6 lipomas, 18 ALT, 1 liposarcoma) were tested for MDM2 amplification. Three of the tested tumors recurred (2 ALT, 1 liposarcoma), and each exhibited MDM2 overamplification. Five tumors (5 liposarcoma) developed late metastases. These data suggest that although ALT is associated with a higher rate of local recurrence, metastases are quite rare. Additionally, the data demonstrate a high rate of positive MDM2 testing (76%) based on clinical and imaging characteristics of the tumors.

Clinical features of multiply recurrent retroperitoneal liposarcoma: A single-center experience

BACKGROUND

To elucidate the clinicopathological features of multiply recurrent retroperitoneal liposarcoma referred to a tertiary center.

METHODS

We retrospectively analyzed the clinical data of 40 patients with pathologically proven primary retroperitoneal liposarcoma treated between January 2015 and June 2019.

RESULTS

The initial pathology was well-differentiated liposarcoma (WDLS) in 23 patients, dedifferentiated liposarcoma (DDLS) in 15 patients, and myxoid liposarcoma in two patients. Before and after referral to our hospital, the patients underwent 142 surgeries (median number of surgeries: 3) for initial and recurrent tumors. Of these, 35 (87.5%) patients underwent surgeries for recurrent tumors. In 11 (47.8%) of the 23 patients with initial WDLS, pathological progression (PP) to DDLS was observed in recurrent tumors at the median interval of 7.8 years. In eight patients (72.7%), the PP occurred at the first recurrence. In contrast, all 15 patients with DDLS recurred as DDLS. Distant metastases developed in eight patients (34.8%) with WDLS and five patients (29.4%) with DDLS/myxoid subtype. All eight WDLS patients who developed metastasis were alive with disease at the median interval of 3.6 years, whereas four of the five patients with primary diagnosis of DDLS/myxoid subtype died at the median interval of 5.6 months from the development of metastasis. The 5-year overall survival of the patients with initial WDLS and those with DDLS/myxoid subtype were 100% and 67.4% (p = 0.0006), respectively.

CONCLUSIONS

The prognosis of the initial-WDLS patients was favorable despite multiple recurrences. In WDLS patients, if distant metastases develop, it is possible to remain alive with disease for years.

Recurrent giant retroperitoneal liposarcoma with 10 years follow up. Case report and review of literature

INTRODUCTION

This case is of a patient with a recurrent giant retroperitoneal liposarcoma, followed-up and operated multiple times over 10 years. We report this case because of its rarity and review all previous articles reporting "Giant Retroperitoneal Liposarcoma" in the English literature.

CASE DESCRIPTION

A 70 years old man presented to our clinic for dizziness and fatigue. He was incidentally found to have a large retroperitoneal mass filling all the length of the abdominal cavity and shifting all intraabdominal viscera and kidney to the left side. En bloc excision of a 50 × 30 × 18 cm, 9 kg tumor was performed. Final pathology revealed a well-differentiated liposarcoma. Five years later, the patient was reoperated for recurrence and a well-differentiated liposarcoma was excised in 2 pieces (the biggest measuring 14 × 11 × 7 cm) along with the appendix. Four years later the patient was operated on again for a second recurrence, and again a well-differentiated liposarcoma (16 × 10 × 7 cm) extending into the right inguinal canal was excised. One year thereafter, the patient was diagnosed with a third recurrence (22 × 12 cm).

DISCUSSION

Retroperitoneal Liposarcomas are rare tumors, presenting with different histological differentiation. They are diagnosed using multiple imaging modality, mainly CT scan, and it is confirmed by percutaneous large core needle biopsy. R0 Surgical excision remains the proper treatment for non-metastatic tumors, which may necessicate multiorgan resection. They rarely grow to reach a large size and be labled as "Giant Retroperitoneal Liposarcoma".

Single centre 30-year experience in treating retroperitoneal liposarcomas

BACKGROUND AND OBJECTIVES

Liposarcomas form a diverse group of tumors that represent the majority of retroperitoneal soft tissue sarcomas. Radical excision of these retroperitoneal liposarcomas is often challenging due to their large size and proximity to visceral organs and major vessels. Here we present the 30-year experience of our multidisciplinary sarcoma team in the treatment of these tumors and analysis of factors influencing survival.

METHODS

Patients with retroperitoneal liposarcomas treated in Helsinki University Hospital from 1987 to 2017 were reviewed. Local recurrence-free survival, metastases-free survival, and disease-specific survival were assessed with Kaplan-Meier analysis, and factors influencing survival were evaluated with Cox regression.

RESULTS

A total of 107 patients were identified. The median follow-up time was 5.4 years (interquartile range: 2.2-8.8 years). Local recurrence developed in 72% and metastases in 15% during follow-up. The 5-year disease-free survival was 31% and disease-specific survival was 66%. The multifactorial analysis revealed histological type and grade as predictors of disease-specific survival (P < .01) while multifocality carried a poor prognosis for local recurrence (P = .02) and higher histological grade for metastases (P < .01).

CONCLUSIONS

Retroperitoneal liposarcomas rarely metastasize but tend to recur locally. For tumors that have been resected with macroscopically clear margins, histological, type, and grade are significant predictors of survival.