Optical Genome Mapping for Comprehensive Cytogenetic Analysis of Soft-Tissue and Bone Tumors for Diagnostic Purposes.

Soft-tissue and bone tumors represent a heterogeneous group of tumors encompassing more than 100 histologic subtypes today. Identifying genetic aberrations increasingly is important in these tumors for accurate diagnosis. Although gene mutations typically are detected by second-generation sequencing, the identification of structural variants (SVs) and copy number alterations (CNAs) remains challenging and requires various cytogenetic techniques including karyotyping, fluorescence in situ hybridization, and arrays, each with important limitations. Optical Genome Mapping (OGM), a non-sequencing-based technique for high-resolution detection of SVs and CNAs, was applied in a retrospective series of diagnostic soft-tissue and bone tumor samples. Sample preparation was successful in 38 of 53 cases, with the highest success rate in nonadipocytic soft-tissue tumors (24 of 27 cases; 89%). In 32 of 35 cases carrying a diagnostic SV or CNA, OGM identified the aberration (91%), including a POU2AF3::EWSR1 fusion in a round cell sarcoma and a translocation t(1;5)(p22;p15) in a myxoinflammatory fibroblastic sarcoma. Interestingly, OGM shed light on the genomic complexity underlying the various aberrations. In five samples, OGM showed that chains of rearrangements generated the diagnostic fusion, three of which involved chromoplexy. In addition, in nine samples, chromothripsis was causal to the formation of giant marker/ring/double-minute chromosomes. Finally, compared with standard-of-care cytogenetics, OGM revealed additional aberrations, requiring further investigation of their potential clinical relevance.

Case report: Cardiac intimal sarcoma in a young child.

Undifferentiated mesenchymal tumors from the intimal layer (intimal sarcomas) are rare within the ventricles and exceptional in children. A rare case of an intimal sarcoma located in the right ventricle in a young child is presented with need for urgent surgical resection due to mechanical flow obstruction. Tumor cells showed amplification of MDM2 gene and a homozygous loss of CDKN2A on 9p21. A review of the literature regarding primary cardiac malignancies and intimal sarcoma in children is provided.

Plocabulin, a Novel Tubulin Inhibitor, Has Potent Antitumour Activity in Patient-Derived Xenograft Models of Soft Tissue Sarcoma.

A clinically relevant subset of patients with soft tissue sarcoma presents with either locally advanced or upfront metastatic disease, or will develop distant metastases over time, despite successful treatment of their primary tumour. The currently available systemic agents to treat such advanced cases only provide modest disease control and are not active in all histological subtypes. Thus, there is an unmet need for novel and more efficacious agents to improve the outcome of this rare disease. In the current preclinical in vivo study, we evaluated plocabulin, a novel tubulin inhibitor, in five distinct histological subtypes of soft tissue sarcoma: dedifferentiated liposarcoma, leiomyosarcoma, undifferentiated sarcoma, intimal sarcoma and CIC-rearranged sarcoma. The efficacy was tested in seven patient-derived xenograft models, which were generated by the engraftment of tumour fragments from patients directly into nude mice. The treatment lasted 22 days, and the efficacy of the drug was assessed and compared to the doxorubicin and vehicle groups by volumetric analysis, histopathology and immunohistochemistry. We observed tumour volume control in all the tested histological subtypes. Additionally, in three sarcoma subtypes, extensive central necrosis, associated with significant tumour regression, was seen. This histological response is explained by the drug's vascular-disruptive properties, reflected by a decreased total vascular area in the xenografts. Our results demonstrate the in vivo efficacy of plocabulin in the preclinical models of soft tissue sarcoma and corroborate the findings of our previous study, which demonstrated similar vascular-disruptive effects in gastrointestinal stromal tumours-another subtype of soft tissue sarcoma. Our data provide a convincing rationale for further clinical exploration of plocabulin in soft tissue sarcomas.

Correlation of Immunological and Molecular Profiles with Response to Crizotinib in Alveolar Soft Part Sarcoma: An Exploratory Study Related to the EORTC 90101 "CREATE" Trial.

Alveolar soft part sarcoma (ASPS) is a rare subtype of soft tissue sarcoma characterized by an unbalanced translocation, resulting in ASPSCR1-TFE3 fusion that transcriptionally upregulates MET expression. The European Organization for Research and Treatment of Cancer (EORTC) 90101 "CREATE" phase II trial evaluated the MET inhibitor crizotinib in ASPS patients, achieving only limited antitumor activity. We performed a comprehensive molecular analysis of ASPS tissue samples collected in this trial to identify potential biomarkers correlating with treatment outcome. A tissue microarray containing 47 ASPS cases was used for the characterization of the tumor microenvironment using multiplex immunofluorescence. DNA isolated from 34 available tumor samples was analyzed to detect recurrent gene copy number alterations (CNAs) and mutations by low-coverage whole-genome sequencing and whole-exome sequencing. Pathway enrichment analysis was used to identify diseased-associated pathways in ASPS sarcomagenesis. Kaplan-Meier estimates, Cox regression, and the Fisher's exact test were used to correlate histopathological and molecular findings with clinical data related to crizotinib treatment, aiming to identify potential factors associated with patient outcome. Tumor microenvironment characterization showed the presence of PD-L1 and CTLA-4 in 10 and 2 tumors, respectively, and the absence of PD-1 in all specimens. Apart from CD68, other immunological markers were rarely expressed, suggesting a low level of tumor-infiltrating lymphocytes in ASPS. By CNA analysis, we detected a number of broad and focal alterations. The most common alteration was the loss of chromosomal region 1p36.32 in 44% of cases. The loss of chromosomal regions 1p36.32, 1p33, 1p22.2, and 8p was associated with shorter progression-free survival. Using whole-exome sequencing, 13 cancer-associated genes were found to be mutated in at least three cases. Pathway enrichment analysis identified genetic alterations in NOTCH signaling, chromatin organization, and SUMOylation pathways. NOTCH4 intracellular domain dysregulation was associated with poor outcome, while inactivation of the beta-catenin/TCF complex correlated with improved outcome in patients receiving crizotinib. ASPS is characterized by molecular heterogeneity. We identify genetic aberrations potentially predictive of treatment outcome during crizotinib therapy and provide additional insights into the biology of ASPS, paving the way to improve treatment approaches for this extremely rare malignancy.

Detection of MDM2 amplification by shallow whole genome sequencing of cell-free DNA of patients with dedifferentiated liposarcoma.

High-level amplification of MDM2 and other genes in the 12q13-15 locus is a hallmark genetic feature of well-differentiated and dedifferentiated liposarcomas (WDLPS and DDLPS, respectively). Detection of this genomic aberration in plasma cell-free DNA may be a clinically useful assay for non-invasive distinction between these liposarcomas and other retroperitoneal tumors in differential diagnosis, and might be useful for the early detection of disease recurrence. In this study, we performed shallow whole genome sequencing of cell-free DNA extracted from 10 plasma samples from 3 patients with DDLPS and 1 patient with WDLPS. In addition, we studied 31 plasma samples from 11 patients with other types of soft tissue tumors. We detected MDM2 amplification in cell-free DNA of 2 of 3 patients with DDLPS. By applying a genome-wide approach to the analysis of cell-free DNA, we also detected amplification of other genes that are known to be recurrently affected in DDLPS. Based on the analysis of one patient with DDLPS with longitudinal plasma samples available, we show that tracking MDM2 amplification in cell-free DNA may be potentially useful for evaluation of response to treatment. The patient with WDLPS and patients with other soft tissue tumors in differential diagnosis were negative for the MDM2 amplification in cell-free DNA. In summary, we demonstrate the feasibility of detecting amplification of MDM2 and other DDLPS-associated genes in plasma cell-free DNA using technology that is already routinely applied for other clinical indications. Our results may have clinical implications for improved diagnosis and surveillance of patients with retroperitoneal tumors.

Histopathological and Molecular Profiling of Clear Cell Sarcoma and Correlation with Response to Crizotinib: An Exploratory Study Related to EORTC 90101 "CREATE" Trial.

Clear cell sarcoma (CCSA) is characterized by a chromosomal translocation leading to EWSR1 rearrangement, resulting in aberrant transcription of multiple genes, including MET. The EORTC 90101 phase II trial evaluated the MET inhibitor crizotinib in CCSA but resulted in only sporadic responses. We performed an in-depth histopathological and molecular analysis of archival CCSA samples to identify alterations potentially relevant for the treatment outcome. Immunohistochemical characterization of MET signaling was performed using a tissue microarray constructed from 32 CCSA cases. The DNA from 24 available tumor specimens was analyzed by low-coverage whole-genome sequencing and whole-exome sequencing for the detection of recurrent copy number alterations (CNAs) and mutations. A pathway enrichment analysis was performed to identify the pathways relevant for CCSA tumorigenesis. Kaplan-Meier estimates and Fisher's exact test were used to correlate the molecular findings with the clinical features related to crizotinib treatment, aiming to assess a potential association with the outcomes. The histopathological analysis showed the absence of a MET ligand and MET activation, with the presence of MET itself in most of cases. However, the expression/activation of MET downstream molecules was frequently observed, suggesting the role of other receptors in CCSA signal transduction. Using sequencing, we detected a number of CNAs at the chromosomal arm and region levels. The most common alteration was a gain of 8q24.21, observed in 83% of the cases. The loss of chromosomes 9q and 12q24 was associated with shorter survival. Based on exome sequencing, 40 cancer-associated genes were found to be mutated in more than one sample, with SRGAP3 and KMT2D as the most common alterations (each in four cases). The mutated genes encoded proteins were mainly involved in receptor tyrosine kinase signaling, polymerase-II transcription, DNA damage repair, SUMOylation and chromatin organization. Disruption in chromatin organization was correlated with longer progression-free survival in patients receiving crizotinib. Conclusions: The infrequent activation of MET may explain the lack of response to crizotinib observed in the majority of cases in the clinical trial. Our work describes the molecular heterogeneity in CCSA and provides further insight into the biology of this ultra-rare malignancy, which may potentially lead to better therapeutic approaches for CCSA.

Comprehensive Molecular Analysis of Inflammatory Myofibroblastic Tumors Reveals Diverse Genomic Landscape and Potential Predictive Markers for Response to Crizotinib.

PURPOSE: The European Organization for Research and Treatment of Cancer (EORTC) clinical phase II trial 90101 "CREATE" showed high antitumor activity of crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK)/ROS1, in patients with advanced inflammatory myofibroblastic tumor (IMFT). However, recent findings suggested that other molecular targets in addition to ALK/ROS1 might also contribute to the sensitivity of this kinase inhibitor. We therefore performed an in-depth molecular characterization of archival IMFT tissue, collected from patients enrolled in this trial, with the aim to identify other molecular alterations that could play a role in the response to crizotinib. EXPERIMENTAL DESIGN: Twenty-four archival IMFT samples were used for histopathological assessment and DNA/RNA evaluation to identify gene fusions, copy-number alterations (CNA), and mutations in the tumor tissue. Results were correlated with clinical parameters to assess a potential association between molecular findings and clinical outcomes. RESULTS: We found 12 ALK fusions with 11 different partners in ALK-positive IMFT cases by Archer analysis whereas we did not identify any ROS1-rearranged tumor. One ALK-negative patient responding to crizotinib was found to have an ETV6-NTRK fusion in the tumor specimen. The CNA profile and mutational landscape of IMFT revealed extensive molecular heterogeneity. Loss of chromosome 19 (25% of cases) and PIK3CA mutations (9% of cases) were associated with shorter progression-free survival in patients receiving crizotinib. CONCLUSIONS: We identified multiple genetic alterations in archival IMFT material and provide further insight into the molecular profile of this ultra-rare, heterogeneous malignancy, which may potentially translate into novel treatment approaches for this orphan disease.

Long-term efficacy update of crizotinib in patients with advanced, inoperable inflammatory myofibroblastic tumour from EORTC trial 90101 CREATE.

PURPOSE: European Organisation for Research and Treatment of Cancer (EORTC) 90101 (CREATE) was a prospective, multicentric, non-randomised, open-label phase II basket trial to assess the efficacy and safety of crizotinib in patients with different types of cancers, including advanced inflammatory myofibroblastic tumour (IMT) with or without anaplastic lymphoma kinase (ALK) rearrangements. Here, we report updated results with long-term follow-up. PATIENTS/METHODS: After central reference pathology, eligible ALK-positive and ALK-negative patients with advanced/metastatic IMT deemed incurable with surgery, radiotherapy or systemic therapy received oral crizotinib 250 mg twice daily. The ALK status was assessed centrally using immunohistochemistry and fluorescence in situ hybridisation. The primary end-point was the proportion of patients who achieved an objective response (i.e. complete or partial response). If ≥6 ALK-positive patients achieved a confirmed response, the trial would be deemed successful. RESULTS: At data cut-off on 28th January 2021, we performed the final analysis of this trial. Of the 20 eligible and treated patients (19 of whom were evaluable for efficacy), with a median follow-up of 50 months, five were still on crizotinib treatment (4/12 ALK-positive and 1/8 ALK-negative patients). The updated objective response rate (ORR) was 66.7% (95% confidence interval [CI] 34.9-90.1%) in ALK-positive patients and 14.3% (95% CI 0.0-57.9%) in ALK-negative patients. In the ALK-positive and ALK-negative patients, the median progression-free survival was 18.0 months (95% CI 4.0-NE) and 14.3 months (95% CI 1.2-31.1), respectively; 3-year overall survival rates were 83.3% (95% CI 48.2-95.6) and 34.3% (95% CI 4.8-68.5). Safety results were consistent with previously reported data. CONCLUSION: These updated results confirm previous findings that crizotinib is effective, with durable responses, in patients with locally advanced or metastatic ALK-positive IMT. With further follow-up after the original primary analysis, the ORR increased, as patients derived long-term benefit and some responses converted from stable disease to partial responses. CLINICAL TRIAL NUMBER: EORTC 90101, NCT01524926.

Management of Synovial Sarcoma in a Tertiary Referral Center: A Retrospective Analysis of 134 Patients.

BACKGROUND: Synovial sarcomas (SS) are malignant mesenchymal neoplasms that account for about 10% of all sarcomas. Complete surgical excision is the mainstay of primary treatment for localized disease, but SS have a high tendency for local relapse and metastases. Metastatic disease is commonly treated with systemic chemotherapy. METHODS: We designed a retrospective analysis to describe the clinical presentation, course of treatment, outcome, and prognosis of patients with SS. Univariate and multivariate analyses were performed for potential prognostic factors. RESULTS: We identified 134 patients treated between 1987 and 2018, with a cutoff date of December 2018. Demographics, disease characteristics, treatment, and survival rates were collected and analyzed. The median overall survival (mOS) from the date of diagnosis was 96.7 months. The median progression-free survival was 6.37 months. Disease-free survival was 26 months. Age over 65 years was found to be a prognostic factor with statistically significant value in the univariate analysis regarding mOS (p = 0.015) and mOS after local relapse (p = 0.0228). CONCLUSIONS: Even though our study is limited by the retrospective nature of the analysis, it adds an important amount of clinical data regarding the treatment and outcome of SS.

Loss of 9p21 Regulatory Hub Promotes Kidney Cancer Progression by Upregulating HOXB13.

Loss of chromosome 9p21 is observed in one-thirds of clear-cell renal cell carcinoma (ccRCC) and is associated with poorer patient survival. Unexpectedly, 9p21 LOH does not lead to decreased expression of the 9p21 tumor suppressor genes, CDKN2A and CDKN2B, suggesting alternative mechanisms of 9p-mediated tumorigenesis. Concordantly, CRISPR-mediated 9p21 deletion promotes growth of immortalized human embryonic kidney epithelial cells independently of the CDKN2A/B pathway inactivation. The 9p21 locus has a highly accessible chromatin structure, suggesting that 9p21 loss might contribute to kidney cancer progression by dysregulating genes distal to the 9p21 locus. We identified several 9p21 regulatory hubs by assessing which of the 9p21-interacting genes are dysregulated in 9p21-deleted kidney cells and ccRCCs. By focusing on the analysis of the homeobox gene 13 (HOXB13) locus, we found that 9p21 loss relieves the HOXB13 locus, decreasing HOXB13 methylation and promoting its expression. Upregulation of HOXB13 facilitates cell growth and is associated with poorer survival of patients with ccRCC. IMPLICATIONS: The results of our study propose a novel tumor suppressive mechanism on the basis of coordinated expression of physically associated genes, providing a better understanding of the role of chromosomal deletions in cancer.

Comprehensive targeted next-generation sequencing approach in the molecular diagnosis of gastrointestinal stromal tumor.

Mutational analysis guides therapeutic decision making in patients with advanced-stage gastrointestinal stromal tumors (GISTs). We evaluated three targeted next-generation sequencing (NGS) assays, consecutively used over 4 years in our laboratory for mutational analysis of 162 primary GISTs: Agilent GIST MASTR, Illumina TruSight 26 and an in-house developed 96 gene panels. In addition, we investigated the feasibility of a more comprehensive approach by adding targeted RNA sequencing (Archer FusionPlex, 11 genes) in an attempt to reduce the number of Wild Type GISTs. We found KIT or PDGFRA mutations in 149 out of 162 GISTs (92.0%). Challenging KIT exon 11 alterations were initially missed by different assays in seven GISTs and typically represented deletions at the KIT intron 10-exon 11 boundary or large insertions/deletions (>24 base pairs). Comprehensive analysis led to the additional identification of driver alterations in 8/162 GISTs (4.9%): apart from BRAF and SDHA mutations (one case each), we found five GISTs harboring somatic neurofibromatosis type 1 (NF1) alterations (3.1%) and one case with an in-frame TRIM4-BRAF fusion not reported in GIST before. Eventually, no driver alteration was found in two out of 162 GISTs (1.2%) and three samples (1.9%) failed analysis. Our study shows that a comprehensive targeted NGS approach is feasible for routine mutational analysis of GIST, thereby substantially reducing the number of Wild Type GISTs, and highlights the need to optimize assays for challenging KIT exon 11 alterations.

Main Repositories and Databases Used in Ewing Sarcoma Research.

Within sarcomas 50 different histological subtypes exist, each with their own molecular and clinical characteristics. The combination of tumor subtype heterogeneity and often a limited number of clinical cases make detailed molecular sarcoma studies challenging, particularly when focusing on individual cohorts. However, the increasing number of publicly available genomics data opens inroads to overcome this obstacle. The international public repositories for high-throughput microarray and next-generation sequence functional genomic data sets submitted by the research community create resources that are freely available for download in a variety of formats. Here, we describe the selected web resources for sarcoma genomics research. These resources support archiving of raw data, processed data, and metadata which are indexed, cross-linked, and searchable.

Plocabulin, a novel tubulin inhibitor, has potent antitumor activity in patient-derived xenograft models of gastrointestinal stromal tumors.

The majority of patients with gastrointestinal stromal tumors (GIST) eventually become resistant with time due to secondary mutations in the driver receptor tyrosine kinase. Novel treatments that do not target these receptors may therefore be preferable. For the first time, we evaluated a tubulin inhibitor, plocabulin, in patient-derived xenograft (PDX) models of GIST, a disease generally considered to be resistant to cytotoxic agents. Three PDX models of GIST with different KIT genotype were generated by implanting tumor fragments from patients directly into nude mice. We then used these well characterized models with distinct sensitivity to imatinib to evaluate the efficacy of the novel tubulin inhibitor. The efficacy of the drug was assessed by volumetric analysis of the tumors, histopathology, immunohistochemistry and Western blotting. Plocabulin treatment led to extensive necrosis in all three models and significant tumor shrinkage in two models. This histological response can be explained by the drug's vascular-disruptive properties, which resulted in a shutdown of tumor vasculature, reflected by a decreased total vascular area in the tumor tissue. Our results demonstrated the in vivo efficacy of the novel tubulin inhibitor plocabulin in PDX models of GIST and challenge the established view that GIST are resistant to cytotoxic agents in general and to tubulin inhibitors in particular. Our findings provide a convincing rationale for early clinical exploration of plocabulin in GIST and warrant further exploration of this class of drugs in the management of this common sarcoma subtype.

Myxoinflammatory fibroblastic sarcoma: an immunohistochemical and molecular genetic study of 73 cases.

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade soft tissue neoplasm preferentially arising in the extremities of young to middle-aged adults characterized histologically by a variegated appearance and absence of a distinctive immunophenotype. Herein we have evaluated a series of 73 cases of MIFS to define potential features and markers that may facilitate diagnosis. An immunohistochemical study with a large panel of antibodies showed strong positivity of the tumor cells for bcl-1 (94.5%), FXIIIa (89%), CD10 (80%), and D2-40 (56%). FISH and array comparative genomic hybridization (aCGH) were performed in a large subset of cases to investigate the utility for detecting the TGFBR3 and OGA t(1;10) rearrangement and BRAF abnormalities. Using a combination of FISH and/or aCGH, t(1;10) was detected in only 3 of 54 cases (5.5%). The aCGH study also demonstrated amplification of VGLL3 on chromosome 3 that was detected in 8 of 20 cases (40%). BRAF alterations were observed by FISH in 4 of 70 cases (5.7%) and correlated with gain of chromosome 3p12 (VGLL3). A novel fusion transcript involving exon 6 of ZNF335 and exon 10 of BRAF was identified in one case. Demonstration of amplification of VGLL3 on chromosome 3 in combination with expression of bcl-1 and FXIIIa may help support the diagnosis, however, due to their low specificity these markers are not sufficient for a definitive diagnosis in the absence of the appropriate clinical-pathological context. Until a more robust genetic or immunohistochemical signature is identified, the diagnosis of MIFS rests on its characteristic clinicopathological features.

Differential antitumor activity of compounds targeting the ubiquitin-proteasome machinery in gastrointestinal stromal tumor (GIST) cells.

The majority of gastrointestinal stromal tumors (GISTs) are driven by oncogenic KIT signaling and can therefore be effectively treated with the tyrosine kinase inhibitor (TKI) imatinib mesylate. However, most GISTs develop imatinib resistance through secondary KIT mutations. The type of resistance mutation determines sensitivity to approved second-/third-line TKIs but shows high inter- and intratumoral heterogeneity. Therefore, therapeutic strategies that target KIT independently of the mutational status are intriguing. Inhibiting the ubiquitin-proteasome machinery with bortezomib is effective in GIST cells through a dual mechanism of KIT transcriptional downregulation and upregulation of the pro-apoptotic histone H2AX but clinically problematic due to the drug's adverse effects. We therefore tested second-generation inhibitors of the 20S proteasome (delanzomib, carfilzomib and ixazomib) with better pharmacologic profiles as well as compounds targeting regulators of ubiquitination (b-AP15, MLN4924) for their effectiveness and mechanism of action in GIST. All three 20S proteasome inhibitors were highly effective in vitro and in vivo, including in imatinib-resistant models. In contrast, b-AP15 and MLN4924 were only effective at high concentrations or had mostly cytostatic effects, respectively. Our results confirm 20S proteasome inhibitors as promising strategy to overcome TKI resistance in GIST, while highlighting the complexity of the ubiquitin-proteasome machinery as a therapeutic target.

The prognostic role of BRAF and WNT pathways activation in kinase inhibitors-naïve clinical stage III cutaneous melanoma.

The results of local-regional advanced melanoma (stage III) management are still not satisfactory. Particularly, there is no personalized treatment in stage III melanoma patients due to the lack of useful classical pathological markers for prognostication of indolent or aggressive course of the disease. The aim of this study was to explore melanoma genomic landscape by means of the mutational profiling of 50 genes influencing carcinogenesis pathways in the randomly selected 93 kinase inhibitor-naïve (KI-naïve) stage III patients. The genomic alterations were found in 27 out of 50 tested genes and at least one pathogenic variant was detected in 77 out of 93 cases (82.7%). Survival rate was negatively affected by the presence of the somatic mutations in AKT1, ATM, CDH1 and SMARCB1, while the BRAF+ status in KI-naïve stage III population correlated with the longer median overall survival. Genomic alterations in WNT pathway correlated with extranodal adipocyte tissue involvement (P = 0.027) and higher number of metastatic lymph nodes (P = 0.045). In terms of survival, the Cox model confirmed the worse prognosis in patients with mutation in the WNT pathway [hazard ratio (HR) = 2.9, P = 0.017], and better prognosis in cases with mutations in BRAF pathway (HR = 0.5, P = 0.004). WNT/ß-catenin pathway alteration was associated with more advanced/aggressive disease. From this perspective, the concept of blocking the activity of the WNT pathway in selected cases appears promising and complementary to the BRAF inhibition therapeutic option for the future.

[Cardiac intimal sarcoma: A case report of a rare tumor with peculiar histopathological findings]. / Le sarcome intimal cardiaque : tumeur rare illustrée par un cas de présentation histopathologique inhabituelle.

Primary cardiac sarcomas are rare tumors with poor prognosis. Intimal sarcoma, a mesenchymal malignant tumor described mainly in the great vessels, may rarely involve the heart. Herein we describe the case of a 70-years-old female who was found to have a left atrial mass during an investigation of a new onset dyspnea. The patient underwent surgery and the resected mass was found to be an intimal sarcoma. The objectives of this report were to describe a case of this rare disease entity and to discuss its pathological and molecular findings based on relevant literature.

Assessment of the platelet-derived growth factor receptor alpha antibody olaratumab in a panel of patient-derived soft tissue sarcoma xenografts.

BACKGROUND: Soft tissue sarcoma (STS) comprises a family of rare, heterogeneous tumors of mesenchymal origin. Single-agent doxorubicin remains the first-line standard-of-care treatment for advanced and inoperable STS, but response rates are only around 15%. In 2016, phase Ib/II clinical trial results reported an overall survival benefit of 11.8 months when combining doxorubicin and the platelet-derived growth factor receptor alpha (PDGFRA)-directed antibody olaratumab compared to doxorubicin alone, without providing a scientific rationale for such unprecedented therapeutic effect. We decided to evaluate the efficacy of olaratumab in a panel of STS patient-derived xenografts (PDX). METHODS: NMRI nu/nu mice were bilaterally transplanted with tumor tissue of patient-derived xenograft models expressing PDGFRA, including models of leiomyosarcoma (UZLX-STS22), malignant peripheral nerve sheath tumor (UZLX-STS39), myxofibrosarcoma (UZLX-STS59) and undifferentiated pleomorphic sarcoma (UZLX-STS84). Mice were randomly divided into four different treatment groups: (1) control, (2) doxorubicin (3 mg/kg once weekly), (3) anti-PDGFRA [olaratumab (60 mg/kg twice weekly) + mouse anti-PDGFRA antibody 1E10 (20 mg/kg twice weekly)] and (4) the combination of doxorubicin and anti-PDGFRA (same dose/schedule as in the single treatment arms). Tumor volume, histopathology and Western blotting were used to assess treatment efficacy. RESULTS: Anti-PDGFRA treatment as a single agent did not reduce tumor growth and did not result in significant anti-proliferative or pro-apoptotic activity. Combining doxorubicin and anti-PDGFRA did not reduce tumor burden, though a mild inhibition of proliferation was observed in UZLX-STS39 and -STS59. A pro-apoptotic effect was observed in all models except UZLX-STS22. Antitumor effects on histology were not significantly different comparing doxorubicin and the combination treatment. Moreover, anti-PDGFRA treatment, both as a single agent as well as combined with doxorubicin, did not result in inhibition of the downstream MAPK and PI3K/AKT signaling pathways. CONCLUSIONS: We were not able to demonstrate significant antitumor effects of anti-PDGFRA treatment in selected STS PDX models, neither alone nor in combination with doxorubicin. This is in line with the very recent results of the phase III clinical trial NCT02451943 ANNOUNCE, which did not confirm the clinical benefit of olaratumab in combination with doxorubicin over single agent doxorubicin.

Molecular Comparison of Imatinib-Naïve and Resistant Gastrointestinal Stromal Tumors: Differentially Expressed microRNAs and mRNAs.

Despite the success of imatinib in advanced gastrointestinal stromal tumor (GIST) patients, 50% of the patients experience resistance within two years of treatment underscoring the need to get better insight into the mechanisms conferring imatinib resistance. Here the microRNA and mRNA expression profiles in primary (imatinib-naïve) and imatinib-resistant GIST were examined. Fifty-three GIST samples harboring primary KIT mutations (exon 9; n = 11/exon 11; n = 41/exon 17; n = 1) and comprising imatinib-naïve (IM-n) (n = 33) and imatinib-resistant (IM-r) (n = 20) tumors, were analyzed. The microRNA expression profiles were determined and from a subset (IM-n, n = 14; IM-r, n = 15) the mRNA expression profile was established. Ingenuity pathway analyses were used to unravel biochemical pathways and gene networks in IM-r GIST. Thirty-five differentially expressed miRNAs between IM-n and IM-r GIST samples were identified. Additionally, miRNAs distinguished IM-r samples with and without secondary KIT mutations. Furthermore 352 aberrantly expressed genes were found in IM-r samples. Pathway and network analyses revealed an association of differentially expressed genes with cell cycle progression and cellular proliferation, thereby implicating genes and pathways involved in imatinib resistance in GIST. Differentially expressed miRNAs and mRNAs between IM-n and IM-r GIST were identified. Bioinformatic analyses provided insight into the genes and biochemical pathways involved in imatinib-resistance and highlighted key genes that may be putative treatment targets.

Retrospective Analysis of Patients with Advanced Liposarcoma in a Tertiary Referral Center.

BACKGROUND: Liposarcoma (LPS) is a common subtype of soft tissue sarcoma. We describe the clinical outcome of patients with advanced LPS treated in a tertiary referral center and explore potential prognostic factors. PATIENTS AND METHODS: We retrospectively reviewed the records of patients with inoperable or metastatic dedifferentiated liposarcoma (DDLPS), myxoid/round cell liposarcoma (MLPS), and pleomorphic liposarcoma (PLPS) diagnosed and/or treated at the University Hospitals Leuven, Leuven, Belgium, between 2000 and 2014. RESULTS: We identified 100 patients with LPS (67 DDLPS, 25 MLPS, and 8 PLPS). Median overall survival from diagnosis of inoperable or metastatic disease was 13.0 months, without substantial variation between histological subtypes. Sixty-seven patients were treated with systemic chemotherapy. The most common first-line chemotherapeutic agents used were doxorubicin (n = 32), doxorubicin + alkylating agent (n = 16), and trabectedin (n = 5). Best response upon first-line treatment was partial/complete response, stable disease, or progressive disease in 17, 25, and 46% of patients, respectively. On multivariate analysis, metastasectomy and objective response or stable disease achieved with first-line chemotherapy were indicators for better overall survival. CONCLUSION: The LPS subtypes analyzed have a poor prognosis and low response rates to chemotherapy. The prognostic factors identified support the concept of offering systemic chemotherapy to patients with inoperable, advanced disease and of considering metastasectomy in eligible patients.