Comprehensive and Integrated Genomic Characterization of Adult Soft Tissue Sarcomas.

Sarcomas are a broad family of mesenchymal malignancies exhibiting remarkable histologic diversity. We describe the multi-platform molecular landscape of 206 adult soft tissue sarcomas representing 6 major types. Along with novel insights into the biology of individual sarcoma types, we report three overarching findings: (1) unlike most epithelial malignancies, these sarcomas (excepting synovial sarcoma) are characterized predominantly by copy-number changes, with low mutational loads and only a few genes (TP53, ATRX, RB1) highly recurrently mutated across sarcoma types; (2) within sarcoma types, genomic and regulomic diversity of driver pathways defines molecular subtypes associated with patient outcome; and (3) the immune microenvironment, inferred from DNA methylation and mRNA profiles, associates with outcome and may inform clinical trials of immune checkpoint inhibitors. Overall, this large-scale analysis reveals previously unappreciated sarcoma-type-specific changes in copy number, methylation, RNA, and protein, providing insights into refining sarcoma therapy and relationships to other cancer types.

Transcriptomic profiles of myxofibrosarcoma and undifferentiated pleomorphic sarcoma correlate with clinical and genomic features.

Myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS) are two common and aggressive subtypes of soft tissue sarcoma. The aim of this study was to assess potential transcriptomic differences between MFS and UPS tumours and to evaluate the extent to which differences in gene expression profiles were associated with genomic and clinical features. The study included 162 patients with tumours diagnosed as MFS (N = 62) or UPS (N = 100). The patients had been diagnosed and treated at two Swedish sarcoma centres during a 30-year period. For gene expression profiling and gene fusion detection all tumours were analysed using RNA-sequencing and could be compared with data on clinical outcome (N = 155), global copy number profiles (N = 145), and gene mutations (N = 128). Gene expression profiling revealed three transcriptomic clusters (TCs) without any clear separation of MFS and UPS. One TC was associated with longer metastasis-free survival. These tumours had lower tumour mutation burden (TMB), were enriched for a copy number signature representative of focal LOH and chromosomal instability on a diploid background, and were relatively immune-depleted. MFS and UPS showed extensive genomic overlap, with whole genome doubling occurring more frequently among the latter. The results support the idea that MFS and UPS tumours have largely overlapping genomic and transcriptomic features, with UPS tumours showing more aggressive behaviour and more complex genomes. Independently of the tumour type, clinically relevant subgroups were revealed by gene expression analysis, and the finding of multiple genomic subgroups strongly suggest the existence of subgroups of relevance to treatment stratification. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

p53 as a Potential Actionable Target in Myxofibrosarcoma: A Molecular and Pathologic Review of a Single-Institute Series.

Myxofibrosarcoma (MFS) is a common adult soft tissue sarcoma characterized by high-local recurrence rate, poorly understood molecular pathogenesis, lack of specific prognostic markers, and effective targeted therapies. To gain further insights into the disease, we analyzed a well-defined group of 133 primary MFS cases. Immunohistochemical (IHC) staining for p53, MET, RET, and RB was performed. Twenty-five cases were analyzed by targeted resequencing of known cancer driver hotspot mutations, whereas 66 and 64 MFSs were examined for the presence of genetic variants in TP53 and MET gene, respectively. All clinical, histologic, immunostaining, and genetic variables were analyzed for their impact on 5-years overall survival (OS) and 5-years event-free survival (EFS). In our series, no grade I tumors relapsed and high grade are related to a positive MET immunostaining (P = .034). Both local recurrence (P = .038) and distal metastases (P = .016) correlated to the presence of "single nucleotide variant (SNV) plus copy number variation (CNV)" in TP53. Multivariate analysis revealed that age (>60 years), metastasis at presentation, and positive IHC-p53 signal are risk factors for a poor OS (P = .003, P = .000, and P = .002), whereas age (>60 years), synchronous metastasis, and tumor size (>10 cm) predict an unfavorable 5-years EFS (P = .011, P = .000, and P = .023). Considering the smaller series (n = 66) that underwent molecular screening, the presence of "SNV+CNV" in TP53 represents a risk factor for a worse 5-years EFS (hazard ratio, 2.5; P = .017). The present series confirms that TP53 is frequently altered in MFS (86.4% of cases), appearing to play an important role in MFS tumorigenesis and being a potentially drugable target. A positive p53 immunostainings is related to a poor diagnosis, and it is the presence of a single nucleotide genetic alterations in TP53 that is essential in conferring MFS an aggressive phenotype, thus supporting the use of molecular profiling in MFS to better define the role of p53 as a prognostic factor.

Localized Myxofibrosarcoma: A Retrospective Analysis of Primary Therapy and Prognostic Factors in 134 Patients in a Single Institution.

BACKGROUND: Primary therapy of localized myxofibrosarcoma (MFS) remains controversial. Primary resection is complicated by a high rate of local recurrence, and the refractoriness to non-surgical treatment results in a higher risk of metastasis. The aim of the present study was to contribute the findings of a single sarcoma-specialized center and encourage investigating new treatment options. PATIENTS AND METHODS: We analyzed 134 patients treated with localized MFS in our center regarding prognostic factors defining overall survival, local recurrence, and metastasis. We focused on multimodal treatment of localized MFS: surgery, radiation, chemotherapy, hyperthermia, and isolated limb perfusion. RESULTS: The 5-year OS was 74.9%. From a total of 134 patients: 74 (55.2%) stayed disease free, 48 (35.8%) had a local recurrence (LR), and 23 (17.2%) developed a distant metastasis (DM). The 5-year LR-free survival (LRFS) and DM-free survival (DMFS) were 66.1% and 80.8%, respectively. Older age, tumor size (cT) cT ≥ 2, non-extremity localization, and distant metastasis were adverse predictive factors for OS. Performing an incision biopsy, surgery in a sarcoma-center, wide local excision or compartment-oriented excision, negative margins, and radiotherapy were positive predictive factors for LR. Tumor size cT ≥ 3 was a negative predictive factor for DM. Grading was a negative predictive factor for LR (G ≥ 2) and for DM (G3) in the multivariable analysis. CONCLUSION: Adjuvant radiation had a positive impact on LRFS in all localized tumor stages, even in cT1 tumors. Chemotherapy did not have a significant impact on DMFS, regardless of tumor stage. Our findings indicate that myxofibrosarcoma may be a chemotherapy-resistant entity and a much closer monitoring is required, in case of neoadjuvant treatment.

The effect of radiation or chemotherapy on the local recurrence, overall survival, and distant metastasis in patients with myxofibrosarcoma: A systematic review.

BACKGROUND AND OBJECTIVES: Management of myxofibrosarcoma (MFS) is widely debated, and there is no consensus regarding the effect of adjuvant therapies on local recurrence (LR), distant metastasis (DM), or overall survival (OS). This study aims to determine the effect of adjuvant therapies on the aforementioned outcomes in patients with MFS. METHODS: We conducted a systematic review via Medline, PubMed, CINAHL, Cochrane, Embase, and Google Scholar. Therapeutic studies that reported LR, DM, and OS following adjuvant therapies in patients with MFS were included. Statistical analysis and creation of hazard ratios were performed using Revman 5.3 (Cochrane Collaboration). RESULTS: We identified 301 studies, 10 of which were included in the final analysis. Neither chemotherapy nor radiation affected the rate of LR (p = 0.73 and 0.17, respectively) or OS (p = 0.97 and 0.27, respectively). Chemotherapy was significantly associated with lower rates of DM (p = 0.03); however, there was no association between radiation and DM (p = 0.67). CONCLUSION: There is a lack of consensus regarding the effect of neoadjuvant and adjuvant therapies on LR, DM, and OS in patients with MFS. Our systematic review found that radiation and chemotherapy were not significantly associated with OS or LR in patients with MFS. However, we identified a significant association between chemotherapy and lower rates of DM.

Wound vacuum-assisted closure temporization after tumor resection of soft tissue sarcomas-A cost analysis in a propensity-score matched population.

BACKGROUND: Vacuum-assisted closure (VAC) temporization is a technique associated with high local control rates used in myxofibrosarcoma. We sought to compare the costs and postoperative outcomes of VAC temporization and single-stage (SS) excision/reconstruction. METHODS: We conducted a retrospective analysis of patients with myxofibrosarcoma surgically treated at our institution between 2000 and 2022. Variables of interest included total, direct, and indirect costs for initial episode of care, 90 days and 1 year after initial admission, and postoperative outcomes. Costs were compared between the VAC temporization and SS groups. RESULTS: After matching, 13 patients in the SS group and 23 in the VAC group were analyzed. We found no difference in median and mean total inpatient costs, between the VAC temporization and SS group. While total 90-day and 1-year costs were higher in the VAC group compared to the SS group, mean costs were similar. There were no differences in postoperative complications between groups. A subanalysis of the entire cohort (n = 139) revealed lower local recurrence and overall death rates in the VAC temporization group. CONCLUSION: VAC temporization had similar inpatient costs and postoperative outcomes to SS excision/reconstruction. While median 90-day and 1-year costs were higher in the VAC group, mean costs did not differ.

The Role of Methylation Analysis in Distinguishing Cellular Myxoma from Low-Grade Myxofibrosarcoma.

Cellular myxoma is a benign soft tissue tumor frequently associated with GNAS mutation that may morphologically resemble low-grade myxofibrosarcoma. This study aimed to identify the undescribed methylation profile of cellular myxoma and compare it to myxofibrosarcoma. We performed molecular analysis on twenty cellular myxomas and nine myxofibrosarcomas and analyzed the results using the methylation-based DKFZ sarcoma classifier. A total of 90% of the cellular myxomas had GNAS mutations (four loci had not been previously described). Copy number variations were found in all myxofibrosarcomas but in none of the cellular myxomas. In the classifier, none of the cellular myxomas reached the 0.9 threshold. Unsupervised t-SNE analysis demonstrated that cellular myxomas form their own clusters, distinct from myxofibrosarcomas. Our study shows the diagnostic potential and the limitations of molecular analysis in cases where morphology and immunohistochemistry are not sufficient to distinguish cellular myxoma from myxofibrosarcoma, particularly regarding GNAS wild-type tumors. The DKFZ sarcoma classifier only provided a valid prediction for one myxofibrosarcoma case; this limitation could be improved by training the tool with a more considerable number of cases. Additionally, the classifier should be introduced to a broader spectrum of mesenchymal neoplasms, including benign tumors like cellular myxoma, whose distinct methylation pattern we demonstrated.

Pathological and radiological response following neoadjuvant treatments in primary localized resectable myxofibrosarcoma and undifferentiated pleomorphic sarcoma of the extremities and trunk wall.

BACKGROUND: To explore the correlation between pathological and radiological response to preoperative treatments and outcome in surgically treated patients with myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS). METHODS: All consecutive patients with primary localized MFS and UPS of the extremities and trunk wall surgically treated with curative intent at our center (2005-2021) were included. Clinical data including residual visible tumor (VT%) on surgical specimen and Response Evaluation Criteria in Solid Tumor (RECIST) were retrieved. Kaplan-Meier curves for overall survival and disease-free survival, and cumulative incidence of local relapse and distant metastasis were estimated in a competing risk framework according to RECIST and VT%, overall and by treatment group. Cox and Fine and Gray multivariable models were performed. RESULTS: Of 693 patients affected by primary MFS and UPS, 233 (66 MFS and 167 UPS) were treated by neoadjuvant chemotherapy (naChT), radiotherapy (naRT), or both (naChT-RT). VT% was ≤5% in 13/46 (28.2%), 24/99 (24.2%), and 40/88 (45.4%) patients, respectively. There were 11/46 (29.7%), 22/99 (22.7%), and 23/88 (26.1%) RECIST partial responses and 18/46 (48.6%), 59/99 (60.8%), and 60/88 (68.2%) RECIST stable disease, respectively. In naChT, a trend for a better survival was observed when VT% ≤5% (p = .09), whereas RECIST partial responses and stable disease had the same outcome. VT% was not associated with outcome in naRT or naChT-RT, whereas RECIST response was. CONCLUSION: In primary localized MFS and UPS treated with neoadjuvant therapies, VT% seems more relevant than size reduction after naChT, whereas the opposite is true when naRT is administered alone or concurrent to ChT.

A novel patient-derived immortalised cell line of myxofibrosarcoma: a tool for preclinical drugs testing and the generation of near-patient models.

BACKGROUND: Myxofibrosarcoma is a rare malignant soft tissue sarcoma characterised by multiple local recurrence and can become of higher grade with each recurrence. Consequently, myxofibrosarcoma represents a burden for patients, a challenge for clinicians, and an interesting disease to study tumour progression. Currently, few myxofibrosarcoma preclinical models are available. METHODS: In this paper, we present a spontaneously immortalised myxofibrosarcoma patient-derived cell line (MF-R 3). We performed phenotypic characterization through multiple biological assays and analyses: proliferation, clonogenic potential, anchorage-independent growth and colony formation, migration, invasion, AgNOR staining, and ultrastructural evaluation. RESULTS: MF-R 3 cells match morphologic and phenotypic characteristics of the original tumour as 2D cultures, 3D aggregates, and on the chorioallantoic membrane of chick embryos. Overall results show a clear neoplastic potential of this cell line. Finally, we tested MF-R 3 sensitivity to anthracyclines in 2D and 3D conditions finding a good response to these drugs. CONCLUSIONS: In conclusion, we established a novel patient-derived myxofibrosarcoma cell line that, together with the few others available, could serve as an important model for studying the molecular pathogenesis of myxofibrosarcoma and for testing new drugs and therapeutic strategies in diverse experimental settings.

The Biological Assessment of Shikonin and ß,ß-dimethylacrylshikonin Using a Cellular Myxofibrosarcoma Tumor Heterogeneity Model.

Myxofibrosarcoma (MFS) is a subtype of soft tissue sarcoma of connective tissue, which is characterized by large intra-tumor heterogeneity. Therapy includes surgical resection. Additional chemotherapy is of limited effect. In this study, we demonstrated the potent anticancer activity of shikonin derivatives in our MFS cellular model of tumor heterogeneity for developing a new therapeutic approach. The impact of shikonin and ß,ß-dimethylacrylshikonin (DMAS) on viability, apoptotic induction, MAPK phosphorylation, and DNA damage response were analyzed by means of two human MFS cell lines, MUG-Myx2a and MUG-Myx2b, derived from a singular tumor tissue specimen. MFS cells showed a dose-dependent inhibition of cell viability and a significant induction of apoptosis. Treatment with shikonin derivatives caused an inhibition of pSTAT3 and an increase in pAKT, pERK, pJNK, and pp38. DMAS and shikonin inhibited the activation of the two master upstream regulators of the DNA damage response, ATR and ATM. MUG-Myx2b, which contains an additional PTEN mutation, was more sensitive in some targets. These data demonstrate the significant antitumorigenic effect of shikonin derivatives in MFS and highlight the importance of intra-tumor heterogeneity in treatment planning.

Unveiling the Genomic Basis of Chemosensitivity in Sarcomas of the Extremities: An Integrated Approach for an Unmet Clinical Need.

Myxofibrosarcoma (MFS) and undifferentiated pleomorphic sarcoma (UPS) can be considered as a spectrum of the same disease entity, representing one of the most common adult soft tissue sarcoma (STS) of the extremities. While MFS is rarely metastasizing, it shows an extremely high rate of multiple frequent local recurrences (50-60% of cases). On the other hand, UPS is an aggressive sarcoma prone to distant recurrence, which is correlated to a poor prognosis. Differential diagnosis is challenging due to their heterogeneous morphology, with UPS remaining a diagnosis of exclusion for sarcomas with unknown differentiation lineage. Moreover, both lesions suffer from the unavailability of diagnostic and prognostic biomarkers. In this context, a genomic approach combined with pharmacological profiling could allow the identification of new predictive biomarkers that may be exploited for differential diagnosis, prognosis and targeted therapy, with the aim to improve the management of STS patients. RNA-Seq analysis identified the up-regulation of MMP13 and WNT7B in UPS and the up-regulation of AKR1C2, AKR1C3, BMP7, and SGCG in MFS, which were confirmed by in silico analyses. Moreover, we identified the down-regulation of immunoglobulin genes in patient-derived primary cultures that responded to anthracycline treatment compared to non-responder cultures. Globally, the obtained data corroborated the clinical observation of UPS as an histotype refractory to chemotherapy and the key role of the immune system in determining chemosensitivity of these lesions. Moreover, our results confirmed the validity of genomic approaches for the identification of predictive biomarkers in poorly characterized neoplasms as well as the robustness of our patient-derived primary culture models in recapitulating the chemosensitivity features of STS. Taken as a whole, this body of evidence may pave the way toward an improvement of the prognosis of these rare diseases through a treatment modulation driven by a biomarker-based patient stratification.

Usefulness of SynCAM3 and cyclin D1 immunohistochemistry in distinguishing superficial CD34-positive fibroblastic tumor from its histological mimics.

Superficial CD34-positive fibroblastic tumor (SCPFT) is a fibroblastic/myofibroblastic soft tissue tumor of rarely metastasizing intermediate malignancy. Some recent studies have described a relationship between SCPFT and PRDM10-rearranged soft tissue tumor (PRT) based on SynCAM3 and PRDM10 expression on immunohistochemistry. We performed CD34, cytokeratin AE1/AE3, SynCAM3, and PRDM10 immunohistochemistry in SCPFT and its histological mimics, including myxoinflammatory fibroblastic sarcoma (MIFS), superficially localized myxofibrosarcoma (MFS), and undifferentiated pleomorphic sarcoma. We also examined cyclin D1 expression because it is expressed in MIFS and MFS. We conducted fluorescence in situ hybridization (FISH) of PRDM10 rearrangement in SCPFT cases. On immunohistochemistry, only SCPFT showed strong and diffuse SynCAM3 expression. SCPFT also exhibited strong nuclear and weak cytoplasmic cyclin D1 expression, which was similar to that observed in MIFS. Two of five SCPFT cases exhibited nuclear PRDM10 expression. FISH revealed PRDM10 split signals in 44% and 24% of tumor cells in two SCPFT cases showing nuclear PRDM10 expression on immunohistochemistry, respectively. A minority of non-SCPFT cases showed focal SynCAM3 expression, but a combination of SynCAM3 and cyclin D1 in addition to CD34 and cytokeratin AE1/AE3 may be useful for the differential diagnosis of SCPFT and its histological mimics.

A pulmonary mass extending into the left atrium through the pulmonary vein: a rare diagnosis with an unusual origin.

INTRODUCTION: Myxofibrosarcoma usually occurs in the extremities of middle-aged to older adults. Metastatic myxofibrosarcomas generally emerge in the lung. In this case report, we aim to present a case of primary pulmonary myxofibrosarcoma with tumor thrombus extending into the left atrium without pulmonary vein or atrial invasion. CASE PRESENTATION: A 55-year-old male who was being followed up due to a pulmonary nodule presented with a mass extending from the left lower lobe to the left atrium. No extrathoracic malignancy was detected in the pre-operative examination. The mass extending into the left atrium without invasion was excised with the lower lobe of the left lung. A post-operative histopathological examination revealed myxofibrosarcoma. CONCLUSION: Very few cases of cervical, thoracic wall, mediastinum and cardiac primary myxofibrosarcoma have been documented, and to the best of our knowledge, only one primary pulmonary myxofibrosarcoma case has previously been reported in the English literature. Here, we present a case of primary pulmonary myxofibrosarcoma that extended to the left atrium through the pulmonary vein. In such rare clinical presentations, intracardiac tumor resection should precede pulmonary resection due to the possibility of catastrophic tumor embolisms.

Epidemiology and survival factors of appendicular myxofibrosarcoma: a SEER-retrospective study.

Background: The low incidence of myxofibrosarcoma (MFS) makes high power studies difficult to perform. Demographic and prognostic factors for MFS and how they differ from all extremity soft tissue sarcomas (STS) are not well understood. The purpose of this study was to characterize a large cohort of patients with MFS and evaluate epidemiologic and survival factors when compared to all STS. Materials and methods: We performed a retrospective review of the Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2015 to identify 1,440 patients diagnosed with MFS and 12,324 with STS. Survival curves were creased using Kaplan-Meier, and Cox regression analyses were performed to identify hazard ratios (HRs). Results: Overall survival was greater for STS than MFS (79% vs. 67%). Patients with MFS had a higher average age at diagnosis than STS (62 vs. 56), and older age was strongly associated with decreased survivorship for MFS (HR = 7.94). A greater proportion of patients under 30 diagnosed with MFS were female when compared to STS (49.6% vs. 45.4%). The incidence of MFS and STS increased over the 15-year period, with MFS increasing at a greater rate than STS (1.25% vs. 2.59%). Survival increased for patients diagnosed after 2008 for both STS (9.4%) and MFS (13.2%). Conclusions: There are differences between patient demographics and survival factors when comparing MFS to all STS. Monitoring changes in demographic and survival trends for rare STS subtypes like MFS is important to improve diagnostic algorithms and treatment options.

The landscape of genetic aberrations in myxofibrosarcoma.

Myxofibrosarcoma (MFS) is a rare subtype of sarcoma, whose genetic basis is poorly understood. We analyzed 69 MFS cases using whole-genome (WGS), whole-exome (WES) and/or targeted-sequencing (TS). Newly sequenced genomic data were combined with additional deposited 116 MFS samples. WGS identified a high number of structural variations (SVs) per tumor most frequently affecting the TP53 and RB1 loci, 40% of tumors showed a BRCAness-associated mutation signature, and evidence of chromothripsis was found in all cases. Most frequently mutated/copy number altered genes affected known disease drivers such as TP53 (56.2%), CDKN2A/B (29.7%), RB1 (27.0%), ATRX (19.5%) and HDLBP (18.9%). Several previously unappreciated genetic aberrations including MUC17, FLG and ZNF780A were identified in more than 20% of patients. Longitudinal analysis of paired diagnosis and relapse time points revealed a 1.2-fold mutation number increase accompanied with substantial changes in clonal composition over time. Our study highlights the genetic complexity underlying sarcomagenesis of MFS.

Ultrasonography in the assessment of primary myxofibrosarcoma in the left atrium: a case report.

BACKGROUND: Cardiac myxofibrosarcoma is a rare cardiac malignant tumor, whose diagnosis is challenging due to its rare and non-specific manifestations. Ultrasound is the most important tool for detecting cardiac tumors. Yet, its diagnostic value in cardiac myxoidfibrosarcoma is rarely reported. Herein, we summarized the ultrasonic manifestations of myxofibrosarcoma in a 72-year-old Han woman. CASE PRESENTATION: The patient presented with crushing chest pain without obvious inducement, lasting 3-5 min each time, which would be relieved after rest, accompanied by palpitation, chest tightness, shortness of breath, dizziness, and syncope. The electrocardiogram (ECG) suggested atrial fibrillation. Ultrasound found two moderate echogenic masses in the left atrium; one was about 48 × 31 mm in size, and the other was about 25 × 24 mm in size. The clinical diagnosis was atrial mass and atrial fibrillation. The patient underwent the operation of left atrial tumor resection + mitral valvuloplasty + atrial fibrillation radiofrequency ablation + left atrial appendectomy. The tumor was completely removed, and the patient did not receive radiotherapy or chemotherapy after surgery. The patient was reexamined by ultrasound at 6, 42, and 91 days after surgery, and no obvious abnormalities were found. On day 115, moderate echoic mass was detected on the posterior wall of the left atrium, nearing the mitral valve ring, with a size of about 28 × 23 mm. Currently, the patient is under follow-up care. CONCLUSION: As the most important examination method for cardiac tumors, cardiac ultrasound has good diagnostic and differential diagnosis value and can be used regularly due to its simplicity and safety. The diagnosis rate of cardiac myxofibrosarcoma can be greatly improved by summarizing the ultrasonographic manifestations of cardiac myxofibrosarcoma and differentiating them from other lesions.

Ultrasound of myxofibrosarcoma.

The ultrasound appearance of myxofibrosarcoma is highly variable corresponding to its variable and at times heterogeneous histopathologic appearance. Myxofibrosarcomas may mimic a benign process and the infiltrative tumor margins may be difficult to precisely delineate on ultrasound imaging. These tumor characteristics pose a diagnostic challenge on ultrasound evaluation. The radiologist should be aware of the variable morphologic presentation and infiltrative nature of myxofibrosarcoma and the limitations of ultrasound in the initial diagnosis, biopsy guidance, and post-surgical follow-up of this tumor.

Individualized Mini-Panel Sequencing of ctDNA Allows Tumor Monitoring in Complex Karyotype Sarcomas.

Soft tissue sarcomas (STS) are rare tumors of mesenchymal origin with high mortality. After curative resection, about one third of patients suffer from distant metastases. Tumor follow-up only covers a portion of recurrences and is associated with high cost and radiation burden. For metastasized STS, only limited inferences can be drawn from imaging data regarding therapy response. To date there are no established and evidence-based diagnostic biomarkers for STS due to their rarity and diversity. In a proof-of-concept study, circulating tumor DNA (ctDNA) was quantified in (n = 25) plasma samples obtained from (n = 3) patients with complex karyotype STS collected over three years. Genotyping of tumor tissue was performed by exome sequencing. Patient-individual mini-panels for targeted next-generation sequencing were designed encompassing up to 30 mutated regions of interest. Circulating free DNA (cfDNA) was purified from plasma and ctDNA quantified therein. ctDNA values were correlated with clinical parameters. ctDNA concentrations correlated with the tumor burden. In case of full remission, no ctDNA was detectable. Patients with a recurrence at a later stage showed low levels of ctDNA during clinical remission, indicating minimal residual disease. In active disease (primary tumor or metastatic disease), ctDNA was highly elevated. We observed direct response to treatment, with a ctDNA decline after tumor resections, radiotherapy, and chemotherapy. Quantification of ctDNA allows for the early detection of recurrence or metastases and can be used to monitor treatment response in STS. Therapeutic decisions can be made earlier, such as the continuation of a targeted adjuvant therapy or the implementation of extended imaging to detect recurrences. In metastatic disease, therapy can be adjusted promptly in case of no response. These advantages may lead to a survival benefit for patients in the future.

RSF1 requires CEBP/ß and hSNF2H to promote IL-1ß-mediated angiogenesis: the clinical and therapeutic relevance of RSF1 overexpression and amplification in myxofibrosarcomas.

Myxofibrosarcoma is genetically complex and lacks effective nonsurgical treatment strategies; thus, elucidation of novel molecular drivers is urgently needed. Reanalyzing public myxofibrosarcoma datasets, we identified mRNA upregulation and recurrent gain of RSF1 and characterized this chromatin remodeling gene. Myxofibrosarcoma cell lines were employed to elucidate the oncogenic mechanisms of RSF1 by genetic manipulation and two IL-1ß-neutralizing antibodies (RD24, P2D7KK), highlighting the regulatory basis and targetability of downstream IL-1ß-mediated angiogenesis. Tumor samples were assessed for RSF1, IL-1ß, and microvascular density (MVD) by immunohistochemistry and for RSF1 gene status by FISH. In vivo, RSF1-silenced and P2D7KK-treated xenografts were analyzed for tumor-promoting effects and the IL-1ß-linked therapeutic relevance of RSF1, respectively. In vitro, RSF1 overexpression promoted invasive and angiogenic phenotypes with a stronger proangiogenic effect. RT-PCR profiling identified IL1B as a top-ranking candidate upregulated by RSF1. RSF1 required hSNF2H and CEBP/ß to cotransactivate the IL1B promoter, which increased the IL1B mRNA level, IL-1ß secretion and angiogenic capacity. Angiogenesis induced by RSF1-upregulated IL-1ß was counteracted by IL1B knockdown and both IL-1ß-neutralizing antibodies. Clinically, RSF1 overexpression was highly associated with RSF1 amplification, IL-1ß overexpression, increased MVD and higher grades (all P ≤ 0.01) and independently predicted shorter disease-specific survival (P = 0.019, hazard ratio: 4.556). In vivo, both RSF1 knockdown and anti-IL-1ß P2D7KK (200 µg twice weekly) enabled significant growth inhibition and devascularization in xenografts. In conclusion, RSF1 overexpression, partly attributable to RSF1 amplification, contributes a novel proangiogenic function by partnering with CEBP/ß to cotransactivate IL1B, highlighting its prognostic, pathogenetic, and therapeutic relevance in myxofibrosarcomas.

Pazopanib-related secondary polycythemia in metastatic myxofibrosarcoma: A case report and review of the literature.

INTRODUCTION: Pazopanib, a tyrosine kinase inhibitor (TKI), is a standard treatment for various tumours, including metastatic non-adipocytic soft-tissue sarcomas. In literature, erythrocytosis has been described as a TKI-related condition. CASE REPORT: A 59-year-old man underwent surgical removal of a sub-scapular mass consistent with myxofibrosarcoma. After distant relapse, he first started chemotherapy, and then Pazopanib. He was found to have increased levels of hemoglobin (Hb) and hematocrit (Hct). He was asymphtomatic, with no history of pulmonary disease nor smoking habit. Erythropoietin (EPO) level was higher than normal. A polycythemia vera was ruled out.Management & outcome: The patient started a prophylactic therapy with lysine acetylsalicylate, and we observed a reduction of Hb, but not Hct. Due to disease progression, we interrupted Pazopanib. After a week from drug discontinuation, Hb levels got back to the normal range, Hct was lowering. We decided not to perform phlebotomy, considering the declining trend in Hb and Hct values and the absence of symptoms. DISCUSSION: We postulated a Pazopanib-related secondary erythrocytosis, since Hb and Hct levels increased from baseline during treatment, then normalized when Pazopanib was discontinued. We used the Naranjo Nomogram to assess the correlation between the adverse effect and Pazopanib, the correlation was "Probable", a score of 5. To the best of our knowledge, this is the first case report of Pazopanib-related secondary polycythemia in a patient with sarcoma. It is important to pay attention to blood count and to any symptoms potentially related to erythrocytosis in patients treated with TKIs.