Wei-Lien Wang

BCOR-CCNB3 fusions are frequent in undifferentiated sarcomas of male children.

The BCOR–CCNB3 fusion gene, resulting from a chromosome X paracentric inversion, was recently described in translocation-negative ‘Ewing-like’ sarcomas arising in bone and soft tissue. Genetic subclassification of undifferentiated unclassified sarcomas may potentially offer markers for reproducible diagnosis and substrates for therapy. Using whole transcriptome paired-end RNA sequencing (RNA-seq) we unexpectedly identified BCOR–CCNB3 fusion transcripts in an undifferentiated spindle-cell sarcoma. RNA-seq results were confirmed through direct RT-PCR of tumor RNA and cloning of the genomic breakpoints from tumor DNA. Five additional undifferentiated sarcomas with BCOR–CCNB3 fusions were identified in a series of 42 pediatric and adult unclassified sarcomas. Genomic breakpoint analysis demonstrated unique breakpoint locations in each case at the DNA level even though the resulting fusion mRNA was identical in all cases. All patients with BCOR–CCNB3 sarcoma were males diagnosed in mid childhood (7–13 years of age). Tumors were equally distributed between axial and extra-axial locations. Five of the six tumors were soft-tissue lesions with either predominant spindle-cell morphology or spindle-cell areas interspersed with ovoid to round cells. CCNB3 immunohistochemistry showed strong nuclear positivity in five tumors before oncologic therapy, but was patchy to negative in post-treatment tumor samples. An RT-PCR assay developed to detect the fusion transcript in archival formalin-fixed tissue was positive in all six cases, with high sensitivity and specificity in both pre- and post-treated samples. This study adds to recent reports on the clinicopathologic spectrum of BCOR–CCNB3 fusion-positive sarcomas, a newly emerging entity within the undifferentiated unclassified sarcoma category and describes a simple RT-PCR assay that in conjunction with CCNB3 immunohistochemistry can be useful in diagnosing these tumors.

The role of chemotherapy in advanced solitary fibrous tumors: a retrospective analysis

BackgroundPatients with advanced solitary fibrous tumors (SFTs) have a poor prognosis; treatment options for recurrent disease are particularly limited. Several novel targeted agents have recently shown promise against advanced SFTs, but the relative efficacy of new agents is difficult to assess because data on the efficacy of conventional chemotherapy for SFTs are limited. We thus sought to estimate the efficacy of conventional chemotherapy for SFTs by reviewing data on tumor response to therapy and progression-free survival from SFT patients who received this therapy.MethodsWe retrospectively analyzed the clinical outcomes of 21 patients with grossly measurable, advanced SFTs (unresectable metastatic disease or potentially resectable primary tumors) who received conventional chemotherapy and follow-up at The University of Texas MD Anderson Cancer Center between January 1994 and June 2007. Best tumor response to therapy was assessed using the Response Evaluation Criteria In Solid Tumors 1.1. The Kaplan-Meier method was used to estimate median progression-free survival (PFS) duration.ResultsOf 21 patients, 4 received more than 1 regimen of chemotherapy, for a total of 25 treatments. Doxorubicin-based chemotherapy was given in 15 cases (60%), gemcitabine-based therapy in 5 cases (20%), and paclitaxel in 5 cases (20%). First-line chemotherapy was delivered in 18 cases (72%). No patients had a complete or partial response, 16 (89%) had stable disease, and 2 (11%) had disease progression. Five patients (28%) maintained stable disease for at least 6 months after first-line treatment. The median PFS duration was 4.6 months. The median overall survival from diagnosis was 10.3 years.ConclusionConventional chemotherapy is effective in controlling or stabilizing locally advanced and metastatic SFTs. Our findings can serve as a reference for tumor response and clinical outcomes in the assessment of novel treatments for SFTs.

Molecular prognosticators of complex karyotype soft tissue sarcoma outcome: a tissue microarray-based study

BACKGROUNDnMolecular markers are currently being utilized as sensitive prognosticators of cancer patient outcome. We sought to identify prognostic biomarkers for complex karyotype soft tissue sarcoma (STS).nnnMATERIALS AND METHODSnA large (n = 205) clinically annotated tissue microarray (TMA) was constructed and immunostained for several tumor-related markers. Staining was scored via an automated Ariol image analysis system; data were statistically analyzed to evaluate the correlation of clinicopathological and molecular variables with overall survival (OS) and local recurrence.nnnRESULTSnMultivariable analysis identified older age [hazard ratio (HR) 1.62, P < 0.0001], nonextremity location (HR 2.95, P = 0.001), high tumor grade (HR 2.5, P = 0.02), and increased matrix metalloproteinase (MMP) 2 expression (HR 1.74, P = 0.04) as predictors for poor OS. Similarly, older age (HR 1.51, P = 0.008), nonextremity location (HR 4.09, P = 0.001), and increased MMP2 expression (HR 6.28, P = 0.006) were all found to correlate with shorter local recurrence-free interval. High nuclear p53 expression was associated with shorter STS local recurrence-free interval, with a trend toward significance.nnnCONCLUSIONSnData presented indicate that a clinically annotated TMA can be utilized to identify STS-related prognostic markers. Specifically, MMP2 and nuclear p53 should be further evaluated for their potential inclusion in complex karyotype STS staging systems.

Extensive adipocytic maturation can be seen in myxoid liposarcomas treated with neoadjuvant doxorubicin and ifosfamide and pre-operative radiation therapy

BackgroundTrabectedin and thioglitazones have been documented to induce adipocytic maturation in myxoid liposarcoma; we have noted this in our experience as well. Intriguingly, we have also encountered this same phenomenon in myxoid liposarcomas exposed to various combinations of neoadjuvant doxorubicin and ifosfamide systemic chemotherapy with preoperative radiation, where the pathological effects have been less characterized. We examined the histological changes, including adipocytic maturation, associated with this treatment in patients with myxoid liposarcoma and evaluated for prognostic significance.MethodsTwenty-two patients were identified with histologically confirmed myxoid liposarcomas (9 with variable hypercellular areas) who were treated with neoadjuvant doxorubicin (75-90 mg/m2/continous infusion over 72h every 3 week) and ifosfamide (2.5 g/m2 daily x 4 every 3 weeks) for 4-6 cycles. Twenty-one patients received pre-operative radiation including 5 with concurrent gemcitabine. Pre- and post-treatment MRI studies were compared for changes in tumor area, fat content and contrast uptake, with the latter two estimated as: none, <25%, 25-49% and >50%. Post-treatment specimens were evaluated for hyalinization, necrosis and adipocytic maturation. Clinical follow-up was obtained.ResultsMedian age was 45 (26-72) years with a median tumor size of 11 (2-18) cm. All occurred in the lower extremities except for one case in the neck. As is common in myxoid liposarcoma, all had extensive treatment changes (>90%) with extensive hyalinization (nu2009=u200916; >90%) or prominent adipocytic maturation (nu2009=u20096; >50%) including 2 cases composed almost entirely of mature-appearing adipose tissue. Variable necrosis was identified (5-30%). MRI revealed a decrease in tumor area in all but one tumor (median, 65%), an increase in fat content in 7 tumors (nu2009=u20092, >50%;nu2009=u20092, 25-50%;nu2009=u20093,<25%), and a decrease in contrast enhancement in most tumors (nu2009=u20095, >50%; nu2009=u20099, 25-49%; nu2009=u20097, <25%). Median follow-up was 57 (12-96) months with 17 alive with no disease/metastases, 3 alive with disease and 2 dead of disease. Six patients developed metastases with median interval of 26 (22-51) months post resection. Four of 6 tumors with increased adipocytic maturation >50% on histology had increased fat detected by MRI (>25%). All 6 are alive but 2 developed metastases. In the remaining patients, 4 developed metastases with 14 alive and 2 dead of disease.ConclusionMyxoid liposarcoma exposed to neoadjuvant doxorubicin and ifosfamide and pre-operative radiation can have prominent adipocytic maturation similar to trabectedin treatment. Myxoid liposarcomas exhibit extensive treatment changes with prominent hyalinization being the most common histological change. Despite this, patients develop metastases regardless of adipocytic maturation. While of unclear significance, no patient with fatty maturation died of disease.

Progressive loss of myogenic differentiation in leiomyosarcoma has prognostic value.

Well‐differentiated leiomyosarcomas show morphologically recognizable smooth muscle differentiation, whereas poorly differentiated tumours may form a spectrum with a subset of undifferentiated pleomorphic sarcomas. The expression of certain muscle markers has been reported to have prognostic impact. We investigated the correlation between the morphological spectrum and the muscle marker expression profile of leiomyosarcoma, and the impact of these factors on patient outcomes.

Cytotoxic and targeted therapy for treatment of pseudomyogenic hemangioendothelioma

Pseudomyogenic hemangioendothelioma (PMH) is a recently described, indolent vascular tumor that usually presents in the distal extremities. PMH typically has a multi-focal presentation and can involve several tissue planes including the dermis, subcutis, muscle, and bone. This soft tissue tumor predominantly affects men between 20 and 50xa0years of age. PMH tumors typically are resected but frequently recur locally; thus, more efficacious treatment options are needed. Herein, we report two cases of patients with PMH who were treated with systemic therapy. To the best of our knowledge, our report is the first to describe a response of PMH either to gemcitabine/taxane cytotoxic chemotherapy or to a mammalian target of rapamycin inhibitor. In the first case, a 45-year-old man with PMH of the right ilium was treated with gemcitabine plus docetaxel. Although chemotherapy was ultimately halted owing to gemcitabine-induced pulmonary toxicity, positron emission tomography-computer tomography scans taken after three cycles of gemcitabine plus docetaxel illustrated a noticeable response to the regimen. In the second case, a 22-year-old man with PMH of the right distal femur and metastases in the left ilium showed no response to gemcitabine plus docetaxel therapy, but underwent surgical resection after cisplatin and doxorubicin resulted in stable disease. DNA sequencing of his tumor revealed the presence of a tuberous sclerosis 1 (TSC1) mutation, so daily everolimus, which inhibits mammalian target of rapamycin, was started. Two months after beginning everolimus, the patient underwent magnetic resonance imaging of the pelvis, which revealed mild shrinkage of PMH metastases in the left iliac bone. Despite the apparent heterogeneity of response to gemcitabine/taxane chemotherapy in our two patients, these two cases indicate that gemcitabine/taxane and mammalian target of rapamycin inhibitor may serve as systemic treatment options for PMH and warrant further investigation.

Positive Tumor Response to Combined Checkpoint Inhibitors in a Patient With Refractory Alveolar Soft Part Sarcoma: A Case Report

A 29-year-old man was initially diagnosed with alveolar soft part sarcoma (ASPS) inMay2011after presenting with acute abdominal pain requiring an exploratory laparotomy for an incarcerated internal jejunal hernia and an inflamed appendix. A 5.4-cm subdiaphragmatic mass was incidentally found during this procedure. The mass was removed. The patient had disease recurrence in May 2012 with distant metastases involving the lung, liver, pericardium, and omentum. The patient underwent surgical extirpation of liver and pericardial lesions. Further progression in lung metastases was noted by September 2012, and the patient underwent a right lung wedge resection. Between December 2012 and June 2015, he received multiple lines of vascular endothelial growth factor receptor (VEGFR)–targetedkinase inhibitors, including sunitinib, pazopanib, and axitinib, but the disease eventually progressed. Stable disease was the best response noted for each of these regimens before progression. Beginning in November 2015, he was treated with two cycles of liposomal doxorubicin with progression of disease.

The SS18-SSX Fusion Oncoprotein Hijacks BAF Complex Targeting and Function to Drive Synovial Sarcoma

Synovial sarcoma (SS) is defined by the hallmark SS18-SSX fusion oncoprotein, which renders BAF complexes aberrant in two manners: gain of SSX to the SS18 subunit and concomitant loss of BAF47 subunit assembly. Here we demonstrate that SS18-SSX globally hijacks BAF complexes on chromatin to activate an SS transcriptional signature that we define using primary tumors and cell lines. Specifically, SS18-SSX retargets BAF complexes from enhancers to broad polycomb domains to oppose PRC2-mediated repression and activate bivalent genes. Upon suppression of SS18-SSX, reassembly of BAF47 restores enhancer activation, but is not required for proliferative arrest. These results establish a global hijacking mechanism for SS18-SSX on chromatin, and define the distinct contributions of two concurrent BAF complex perturbations.

Clinical characteristics and treatment outcome in a large multicentre observational cohort of PDGFRA exon 18 mutated gastrointestinal stromal tumour patients

PURPOSEnPatients, platelet-derived growth factor receptor alpha (PDGFRA) D842V-mutated gastrointestinal stromal tumours (GISTs) are known for their insensitivity to imatinib. However, in clinical practice responses have been observed in some patients. We describe the natural history and treatment outcomes in a cohort of PDGFRA exon 18 mutated GIST patients.nnnPATIENTS AND METHODSnA retrospective cohort study was conducted in PDGFRA exon 18 mutation GIST patients treated in six expert centres in the Netherlands and the United States. Two independent radiologists assessed radiological response to imatinib according to Chois criteria in all patients with measurable disease treated with imatinib in neo-adjuvant or palliative intent.nnnRESULTSnSeventy-one patients with PDGFRA exon 18 mutation were identified of whom 48 patients (69%) had a D842V mutation. Twenty-two (45.8%) D842V-mutated GIST patients received imatinib treatment, 16 had measurable disease. Fourteen out of the 23 (60.9%) patients with non-D842V mutations received imatinib treatment, eight had measurable disease. Two out of 16 (12.5%) D842V-mutated GIST patients had partial response, 3 patients (18.8%) had stable disease and 9 patients (56.3%) had progressive disease as best response. Two patients did not have follow-up computed tomography scans to assess response. Six out of 8 (75%) patients with non-D842V exon 18 mutations had partial response and two (25%) had stable disease as best response.nnnCONCLUSIONnPatients with D842V-mutated GISTs can occasionally respond to imatinib. In the absence of better therapeutic options, imatinib should therefore not be universally withheld in patients with this mutation.

AXL is a potential therapeutic target in dedifferentiated and pleomorphic liposarcomas

BackgroundAXL is a well-characterized, protumorigenic receptor tyrosine kinase that is highly expressed and activated in numerous human carcinomas and sarcomas, including aggressive subtypes of liposarcoma. However, the role of AXL in the pathogenesis of well-differentiated (WDLPS), dedifferentiated (DDLPS), and pleomorphic liposarcoma (PLS) has not yet been determined.MethodsImmunohistochemical analysis of AXL expression was conducted on two tissue microarrays containing patient WDLPS, DDLPS, and PLS samples. A panel of DDLPS and PLS cell lines were interrogated via western blot for AXL expression and activity and by ELISA for growth arrest-specific 6 (GAS6) production. AXL knockdown was achieved by siRNA or shRNA. The effects of AXL knockdown on cell proliferation, migration, and invasion were measured in vitro. In addition, AXL shRNA-containing DDLPS cells were assessed for their tumor-forming capacity in vivo.ResultsIn this study, we determined that AXL is expressed in a subset of WDLPS, DDLPS, and PLS patient tumor samples. In addition, AXL and its ligand GAS6 are expressed in a panel of DDLPS and PLS cell lines. We show that the in vitro activation of AXL via stimulation with exogenous GAS6 resulted in a significant increase in cell proliferation, migration, and invasion in DDLPS and PLS cell lines. Transient knockdown of AXL resulted in attenuation of these protumorigenic phenotypes in vitro. Stable AXL knockdown not only decreased migratory and invasive characteristics of DDLPS and PLS cells in vitro but also significantly diminished tumorigenicity of two dedifferentiated liposarcoma xenograft models in vivo.ConclusionsOur results suggest that AXL signaling contributes to the aggressiveness of DDLPS and PLS, and that AXL is therefore a potential therapeutic target for treatment of these rare, yet devastating tumors.