Sarcomas With RAD51B Fusions Are Associated With a Heterogeneous Phenotype

RAD51B-rearranged sarcomas are rare neoplasms that exhibit a heterogeneous morphology. To date, 6 cases have been reported, all involving the uterus, including 4 perivascular epithelioid cell tumors (PEComas) and 2 leiomyosarcomas (LMS). In this study, we describe the morphologic, immunohistochemical, and molecular features of 8 additional sarcomas with RAD51B rearrangement, including the first extrauterine example. All patients were women with a median age of 57 years at presentation. Seven tumors originated in the uterus, and one in the lower extremity soft tissue, with a median tumor size of 12 cm. Histologically, 4 tumors showed predominantly spindle cell morphology with eosinophilic fibrillary cytoplasm, with or without nuclear pleomorphism, whereas 2 tumors exhibited pleomorphic epithelioid cells, featuring clear to eosinophilic, granular cytoplasm. Two neoplasms exhibited undifferentiated cytomorphology, including one with uniform small blue round cells. All tumors showed high-grade cytologic atypia and high mitotic activity (median: 30/10 high-power fields), whereas coagulative necrosis was noted in 6 cases and lymphovascular invasion in 2. By immunohistochemistry, 2 showed myoid and melanocytic markers in keeping with PEComa, whereas 4 cases were only positive for smooth muscle markers consistent with LMS (including 3 myxoid). The remaining 2 cases had a nonspecific immunoprofile. Five cases tested by targeted RNA sequencing (Archer FusionPlex, Illumina TruSight) showed different fusion partners (HMGA2, PDDC1, and CEP170). RAD51B rearrangements were identified by FISH in the remaining 3 cases. Targeted DNA sequencing in 2 cases was negative for TSC gene alterations. Clinical outcome, available in 5 patients (median follow-up, 19 months), revealed 3 local recurrences, 2 lung metastases, and 4 deaths due to disease. Our results expand the spectrum of sarcomas with RAD51B fusions, demonstrating variable clinical presentations, morphologic spectrum, and fusion partners. These tumors have a predilection for a uterine location, with either LMS, PEComa, or undifferentiated phenotypes, and are associated with an aggressive clinical course.

Adamantinoma-like Ewing Sarcoma (ALES) May Harbor FUS Rearrangements : A Potential Diagnostic Pitfall

Adamantinoma-like Ewing sarcoma (ALES) is a rare malignancy currently considered a variant of Ewing sarcoma with most known cases harboring EWSR1 rearrangements. Herein we present a series of 6 cases of EWSR1 -negative ALES. The tumors arose in the sinonasal tract (n=3), major salivary glands (submandibular gland=1; parotid=1), and anterior mediastinum (n=1) in patients ranging from 25 to 79 years of age. Most tumors were basaloid in appearance, growing in large nests separated by interlobular fibrosis without overt squamous pearls. However, 1 case closely resembled a well-differentiated neuroendocrine tumor with uniformly round nuclei, eosinophilic cytoplasm, and trabecular architecture. All cases were diffusely positive for pan-cytokeratin, p40 or p63, and CD99. A subset of cases showed diffuse reactivity for synaptophysin, including 1 sinonasal tumor which also demonstrated sustentacular S100 protein expression. Molecular testing showed FUS rearrangements in all cases. Gene partners included known ETS family members FEV (n=2) and FLI1 (n=1). Our results expand the molecular diagnostic considerations for ALES to include FUS rearrangements. We also show that ALES may harbor FUS :: FLI1 fusion, which has not been previously reported in the Ewing family of tumors. Furthermore, ALES may show unusual histologic and immunophenotypic features that can overlap with olfactory carcinoma including S100-positive sustentacular cells. ALES should be considered in the diagnostic differential of small round cell tumors and tumors with neuroendocrine differentiation with immunohistochemical workup to include p40 and CD99/NKX2.2.

Embryonic stem cell factor FOXD3 (Genesis) defects in gastrointestinal stromal tumors

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms, believed to originate from the interstitial cells of Cajal (ICC), often caused by overexpression of tyrosine kinase receptors (TKR) KIT or PDGFRA. Here, we present evidence that the embryonic stem cell factor FOXD3, first identified as 'Genesis' and involved in both gastrointestinal and neural crest cell development, is implicated in GIST pathogenesis; its involvement is investigated both in vitro and in zebrafish and a mouse model of FOXD3 deficiency. Samples from a total of 58 patients with wild-type GISTs were used for molecular analyses, including Sanger sequencing, comparative genomic hybridization, and methylation analysis. Immunohistochemistry and western blot evaluation were used to assess FOXD3 expression. Additionally, we conducted in vitro functional studies in tissue samples and in transfected cells to confirm the pathogenicity of the identified genetic variants. Germline partially inactivating FOXD3 sequence variants (p.R54H and p.Ala88_Gly91del) were found in patients with isolated GISTs. Chromosome 1p loss was the most frequent chromosomal abnormality identified in tumors. In vitro experiments demonstrate the impairment of FOXD3 in the presence of those variants. Animal studies showed disruption of the GI neural network and changes in the number and distribution in the ICC. FOXD3 suppresses KIT expression in human cells; its inactivation led to an increase in ICC in zebrafish, as well as mice, providing evidence for a functional link between FOXD3 defects and KIT overexpression leading to GIST formation.

Abstract B008: Investigating the evolution of undifferentiated soft tissue sarcomas in a genetically engineered mouse model

Undifferentiated soft tissue sarcomas (USTS) are an aggressive class of sarcomas with few effective treatment options. Because of the rarity of these sarcomas and the paucity of representative disease models, little is known about how they develop. We used single cell transcriptomics to study the initiation and evolution of an USTS in an autochthonous genetically engineered mouse model. We profiled multiple stages of tumor development and identified intermediary cell states that define sarcomagenesis. Interestingly, we identify two discrete evolutionary pathways that arise in parallel in the mouse model. To determine the human relevance of our findings, we are developing machine learning approaches to compare cell states between the mouse model with single-cell transcriptomes that we generated from patient-derived xenografts. This cross-species comparison will uncover core USTS cell states and define their ancestral state transitions. Our ultimate goal is to identify essential molecular features of USTS, which may represent entry points for future therapeutic strategies.

Citation Format: Jason E. Chan, Jonathan Rub, Carleigh Sussman, Olivera Grbovic-huezo, William D. Tap, Cristina Antonescu, Sam Singer, Doron Betel, Tuomas Tammela. Investigating the evolution of undifferentiated soft tissue sarcomas in a genetically engineered mouse model [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr B008.

Abstract PR012: Targeted sequencing of 2,138 bone and soft tissue sarcomas reveals commonly altered pathways, subtype-independent genetic clusters, and potential therapeutic targets

A hallmark of sarcomas is genetic, biologic, and clinical heterogeneity, which is a challenge for preclinical development of therapeutic targets, clinical trial design, and patient care. Because sarcomas comprise over 100 subtypes, a broad comparative genetic analysis of subtypes has been lacking and sarcoma genetic studies have by necessity focused on one or a few subtypes. We will report the results of a comprehensive analysis of somatic genetic alterations detected by a targeted sequencing platform in a single institution cohort of 2,138 patient-specific samples of soft tissue and bone sarcoma representing 45 distinct pathological entities. We determined subtype-specific mutation and copy number (arm and gene level) events with a focus on pathways in which there are therapeutic targets under clinical or preclinical investigation. The most commonly altered pathways are cell cycle control, TP53, PI3K, receptor tyrosine kinase/RAS, and epigenetic regulators (e.g. >40% of uterine leiomyosarcoma [n=165], undifferentiated pleomorphic sarcoma [UPS, n=145] and pleomorphic liposarcoma [n=22]). Subtype-specific associations in rare subtypes include TERT amplification in 41% of intimal sarcoma (n=18) and alterations in chromatin remodeling and histone modifying complexes in uterine adenosarcoma (43% and 36%, respectively; n=14). Epigenetic pathway alterations in common sarcomas were also noted, including an increased frequency of oncogenic alterations in epigenetic regulators in dedifferentiated liposarcoma (DDLS; n=167) (25%) vs. well differentiated liposarcoma (8%; n=48). We evaluated rates of whole genome doubling (WGD), which in subtypes such as UPS and osteosarcoma (n=129) were >45%, which is more frequent than many carcinomas. WGD associated with worse overall survival in metastatic (p=0.042) but not primary samples (p=0.391). Among specific subtypes, WGD was associated with worse overall survival in metastatic UPS (p=0.022). Unsupervised clustering of samples based on genetic features revealed that in some cases sarcomas are more similar to individual tumors of distinct histology than to other sarcomas of the same subtype. For example, UPS and soft tissue leiomyosarcoma (n=125) segregated into multiple genetic clusters (high entropy) compared to others with low entropy (DDLS), which could have implications for future clinical trial interpretation and/or design. We also determined the subtype-specific rate of tumor mutation burden, which was overall low compared to many carcinomas, but notably varied between and within subtypes, with some having a long tail in the upper range of the distribution. Lastly, we assessed targetable alterations on a subtype-specific basis. Together with other ‘multiomic’ approaches, we anticipate this work will motivate preclinical studies of subtype-specific sarcoma biology and potential therapeutic targets and will inform efforts to interpret outcomes in sarcoma clinical trials with respect to underlying genetic subtypes.

Citation Format: Benjamin A. Nacev, Francisco Sanchez-Vega, Shaleigh Smith, Cristina Antonescu, Evan Rosenbaum, Hongyu Shi, Cerise Tang, Nicholas Socci, Satshil Rana, Rodrigo Gularte-Merida, Ahmet Zehir, Mrinal Gounder, Timothy Bowler, Anisha Luthra, Bhumika Jadeja, Azusa Okada, Jonathan Strong, Jake Stoller, Jason Chan, Ping Chi, Sandra D'Angelo, Mark Dickson, Ciara Kelly, Mary Louise Keohan, Sujana Movva, Katherine Thornton, Paul Meyers, Leonard Wexler, Emily Slotkin, Julia Glade Bender, Neerav Shukla, Martee Hensley, John Healey, Michael La Quaglia, Kaled Alektiar, Aimee Crago, Sam Yoon, Brian Untch, Sarah Chiang, Narasimhan Agaram, Meera Hameed, Michael Berger, David Solit, Nikolaus Schultz, Marc Ladanyi, Samuel Singer, William Tap. Targeted sequencing of 2,138 bone and soft tissue sarcomas reveals commonly altered pathways, subtype-independent genetic clusters, and potential therapeutic targets [abstract]. In: Proceedings of the AACR Special Conference: Sarcomas; 2022 May 9-12; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2022;28(18_Suppl):Abstract nr PR012.

1188 Test Characteristics of a Machine Learned Electronic Medical Record Extractable Tool for OSA Case Identification in a Community-Based Population

Introduction

Obstructive sleep apnea (OSA) is a significantly underdiagnosed medical condition. A machine learning method known as SLIM (Supersparse Linear Integer Models) that can be extracted from the Electronic Health Record (EHR) has found to be superior to patient-reported sleep-related symptoms to diagnose OSA. Such an evaluation, however, was previously validated in a laboratory-based population. Our aim was to determine the test characteristics for the EHR-extractable SLIM tool in a community-based population.

Methods

Subjects who participated in the Sleep Heart Health Study (SHHS) were included in this analysis. Variable definitions of OSA were determined using an Apnea Hypopnea Index (AHI) threshold of 5 per hour, 15 per hour, or the presence of any comorbidity (hypertension, ischemic heart disease, stroke, mood disorders, impairment of cognition, or sleepiness) when the AHI was between 5 to 15 per hour. Variable hypopnea definitions based upon degree of oxygen desaturation and associated arousals were considered.

Results

In the SHHS dataset, the Receiver Operating Characteristics (ROC) for a SLIM score threshold of 9 for men and 5 for women was good when OSA was defined by AHI > 5 per hour (hypopneas with either > 3% oxygen desaturation or arousals). Specifically, the ROC was 0.72 (95% Confidence Intervals [CI] 0.70; 0.74) with a Positive Predictive Value [PPV] of 0.98 and Likelihood Ratio of a positive test (LR+) of 11.3. The LR+ (6.0) and PPV (0.92) were also good when an AHI of 5 per hour threshold was adopted with hypopneas scored using the minimum 3% oxygen desaturation alone. Similarly, the ROC was good 0.74 (95%CI 0.73; 0.76) with a Positive Predictive Value [PPV] of 0.98 and Likelihood Ratio of a positive test (LR+) of 11.3. The LR+ (8.9) and PPV (0.81) were also good in the presence of comorbidities when AHI was 5 to 15 per hour using > 4% oxygen desaturation alone.

Conclusion

The EHR-extractable tool can be an actionable tool for case-identification of patients needing a referral for sleep study in a community-based population. Such an approach could facilitate an automated, rather than manual, OSA screening approach aimed at managing population health.

Support

HL138377

EWSR1/FUS-NFATc2 rearranged round cell sarcoma: clinicopathological series of 4 cases and literature review

The classification of bone neoplasms composed of small round cells is experiencing a transformation after the discovery of various gene fusion rearrangements that determine diagnosis, behavior, and response to therapy. We present herein 4 new cases of small round cell tumor of the bone that harbor NFATc2 rearrangements involving either EWSR1 or FUS genes. We studied the clinical presentation, pathologic features, genetics (FISH, targeted RNA sequencing) and outcome in these 4 patients. We also reviewed the literature describing similar cases. All our patients were male. The median age at diagnosis was 33.5 years. All tumors presented in long bones of the extremities as a large destructive mass with a mean size of 12.5 cm. All cases were hypercellular with prominent collagenous stroma and consisted of small to medium size round cells arranged in cords, thin trabeculae, and pseudoacinar structures. Most cases showed focal or diffuse membrane staining for CD99; whereas S100, synaptophysin and chromogranin were negative. EMA showed cytoplasmic staining in one case. Genetic studies identified EWSR1-NFATc2 fusion in 3 cases, and FUS-NFATc2 fusion in one case. Two patients were treated with neoadjuvant chemotherapy using Ewing sarcoma regimens, and surgical excision was performed on 3 patients; necrosis was minimal. Follow-up is limited; after a median follow-up of 8.7 months, one patient developed local recurrence and metastases to the lungs. Poorly differentiated round cell sarcoma with EWSR1/FUS-NFATc2 fusions are uncommon. The tumors have consistent clinical findings, morphology, and immunoprofile that in combination are distinctive and differ from that of Ewing sarcoma. Importantly, these tumors do not respond to Ewing sarcoma chemotherapy regimens.

PDLIM7 and CDH18 regulate the turnover of MDM2 during CDK4/6 inhibitor therapy-induced senescence

CDK4/6 inhibitors are being used to treat a variety of human malignancies. In well-differentiated and dedifferentiated liposarcoma their clinical promise is associated with their ability to downregulate the MDM2 protein. The downregulation of MDM2 following treatment with CDK4/6 inhibitors also induces many cultured tumor cell lines derived from different types of malignancies to progress from quiescence into senescence. Here we used cultured human cell lines and defined a role for PDLIM7 and CDH18, regulating MDM2 protein in CDK4/6 inhibitor-treated cells. Materials from our previous phase II trials with palbociclib were then used to demonstrate that expression of CDH18 protein was associated with response, measured as both progression-free survival and overall survival. This supports the hypothesis that the biologic transition from quiescence to senescence has clinical relevance for this class of drugs.

Abstract IA19: Emerging genetic mechanisms in undifferentiated round cell sarcomas

Undifferentiated round cell sarcomas (URCS) occurring in pediatric and young adults are defined by a primitive morphology reminiscent of Ewing sarcoma, but lack the canonical EWSR1-ETS gene fusion. More than >90% of EWSR1-negative URCS are instead characterized by either a CIC-DUX4 fusion or a genetic abnormality involving BCOR. The latter group includes intra-chromosomal paracentric inversions (BCOR-CCNB3), inter-chromosomal fusions (BCOR-MAML3), or BCOR internal tandem duplications (ITD). Irrespective of their variable mechanism for dysregulation, the tumors share a similar phenotype and a BCOR upregulation at transcriptional and protein levels. In contrast, CIC-DUX4 URCS are characterized by a distinct transcriptional upregulation of PEA3 transcription factors (ETV1/4/5). For practical and treatment purposes, URCS have been regarded as “Ewing sarcoma-like” and have been managed similarly to the Ewing sarcoma family of tumors, despite their poor chemotherapy responses and aggressive clinical behavior. Alternatively these tumors are grouped by default in an “undifferentiated sarcoma category,” with their clinical management being often biased. Despite the wide spectrum of genetic abnormalities, the unifying concept is that the various gene partners or ITDs disrupt the C-terminal repressor domains of both CIC and BCOR, resulting in an oncogenic transcriptional activation of target genes. In URCS with BCOR ITD, the ITD sequences located at the C-terminal may affect the PUFD domain conformation of the BCOR protein, which might interfere with PCGF1 binding and thus could affect the PRC1-related epigenetic modifications.

Citation Format: Cristina Antonescu. Emerging genetic mechanisms in undifferentiated round cell sarcomas [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr IA19.

Abstract PR16: Multiplatform analysis of paired primary and recurrent well- and dedifferentiated liposarcoma samples defines copy number alterations as dominant drivers of initiation and progression

Objective: Initiation of well-differentiated (WD) and dedifferentiated (DD) liposarcoma is driven by 12q13-15 amplification and consequent MDM2 and CDK4 overexpression, but mechanisms that regulate the variable biologic behavior of WD/DD tumors remain poorly understood. We used a multiplatform analysis of paired WD and DD samples to identify genomic events with potential to contribute to liposarcomagenesis.

Methods: From serial tumor resections performed on the same patient, we collected paired WD/DD (n=7) or WD/WD (n=2) test samples and normal tissue. Samples were analyzed using whole-exome sequencing, array comparative genomic hybridization (aCGH), Solexa small RNA sequencing, and, in a subset, RNA-seq. Findings were validated in WD/DD cohorts analyzed by custom capture array (n=201), aCGH (n=210), Affymetrix U133A microarrays (n=146), and Solexa (n=118). Lentivirus was used to deliver shRNA to WD cells in vitro; proliferation was assayed by CyQuant, differentiation by immunoblot/oil red O staining, and gene expression by Illumina microarrays.

Results: 12q13-15 amplification was observed in all WD/DD test and validation samples. Among WD samples, 1q21-24 and 6q23-25 amplifications were found in test samples and in 28% and 18% of the validation set, respectively. Of genes upregulated in WD vs. normal fat test samples, 465 were validated in the larger cohort [≥2-fold change (FC), FDR<0.05]. 53% of these genes lie within regions of copy number alteration (CNA); 8% were predicted targets of 12q-encoded miRNAs. shRNA targeting of MDM2 or drug inhibition of CDK4 in vitro negatively regulated 11% of the genes, including AURKA and its regulators TPX2 and KIF11. 6q23-25 amplification was associated with local recurrence (LR) after primary WD resection (HR 10.9, p<0.001) and with overexpression of CCDC28A and TAB2, an AP-1 regulator (1.7- and 1.9-FC, FDRs<0.05). In 6q23-25-amplified WD cells, shRNA-mediated TAB2 inhibition reduced proliferation by >90%. Comparison of matched WD/DD samples showed retained amplification of 12q13-15 and 6q23-25 after progression. In contrast to WD, DD showed strong association of the 6q23-25 CNA with increased expression of 6q genes TCF21 and HBS1L (16- and 4-FC, FDRs<0.001), but not TAB2 or CCDC28A, suggesting that additional progression events alter the oncogenic effects of initiation-associated CNAs in DD vs WD. Direct comparison of paired DD/WD test samples revealed recurrent 13q loss arising during dedifferentiation (n=3). 13q loss was found in 28% of the DD validation set and associated with reduced expression of 13q genes MYCBP2 and IRS2, regulators of insulin signaling. shRNA inhibition of MYCBP2 or IRS2 in vitro had little effect on WD differentiation, but inhibition of both genes decreased levels of PPARG, FABP4, PLIN and oil red O staining (70% reduction). Uncommon mutations in genes regulating steroid-hormone activation (e.g., NCOA6, KMT2C), adaptive immunity (e.g., LILRA1, NFKB1), and RTK signaling (e.g., NRG1, FGFR1) were identified in 11%, 6%, and 11% of WD/DD samples, respectively, but did not associate with differentiation.

Conclusions: Genes upregulated during WD initiation are commonly located in regions of CNA or regulated by 12q23-25 oncogenes MDM2 and CDK4 (e.g., AURKA, a potential therapeutic target). 6q23-26 amplification, observed in subsets of both WD and DD, associates with LR of WD, but expression of 6q23-26 genes with potential to modulate oncogenesis (e.g., TAB2 vs TCF21) differs in WD and DD tumors, suggesting that the CNA may differentially modulate early and late disease. Losses affecting broad chromosome regions such as 13q likely mediate progression by affecting multiple regulators of adipogenesis pathways (e.g., insulin signaling), while mutations have little effect on dedifferentiation.

Citation Format: Aimee M. Crago, Nicholas D. Socci, Li-Xuan Qin, Fatima Wilder, Rachael O'Connor, Amanda Craig, Willem van Houdt, Nils Weinhold, Cyriac Kandoth, Agnes Viale, Cristina Antonescu, Sam Singer. Multiplatform analysis of paired primary and recurrent well- and dedifferentiated liposarcoma samples defines copy number alterations as dominant drivers of initiation and progression [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr PR16.

Abstract B13: COP1-ETS axis regulates ERK transcriptional output and modulates sensitivity to MAPK inhibitors

Aberrant activation of the mitogen activate kinase (MAPK) pathway is highly prevalent in cancer and therapies targeting the pathway are approved or under active investigation in multiple malignancies. MAPK signaling leads to activation of a transcriptional program that includes general growth promoting genes, negative feedback regulators of the MAPK pathway, and lineage-specific genes. While the mechanisms of upstream signal transduction that leads to MAPK activation have been studied in detail, how MAPK activation is dynamically coupled with downstream nuclear transcriptional response is not fully understood. In gastrointestinal stomal tumor (GIST) and melanoma, two malignancies with aberrant MAPK activation, we find that Pea3 family ETS transcription factors ETV1, ETV4, and ETV5 are critical nuclear effectors of MAPK signaling. We find that the primary mechanism linking MAPK and Pea3 activity is through protein stability via the COP1 E3 ligase. The loss of COP1 leads to decoupling between upstream MAPK signaling and downstream transcription with constitutively stabilized Pea3 protein levels, constitutively high MAPK transcriptome, yet decreased upstream signaling due to Pea3-mediated transcription of negative feedback regulators. This leads to decreased therapeutic sensitivity to MAPK pathway inhibition in vitro and in vivo. These observations indicate that MAPK signaling-dependent regulation of Pea3 ETS protein stability is a crucial pathway that couples downstream transcriptional response to MAPK signaling and can shape the therapeutic sensitivity to MAPK pathway inhibition in cancer.

Citation Format: Yuanyuan Xie, Zhen Cao, Wai Pung Wong, Youxin Guan, Jenny Zhang, Edward Walczak, Devan Murphy, Leili Ran, Inna Sirota, Shangqian Wang, Shipra Shukla, Dong Gao, John Wongvipat, Simon Knott, Kenneth Chang, Cristina Antonescu, Gregory Hannon, Ping Chi, Yu Chen. COP1-ETS axis regulates ERK transcriptional output and modulates sensitivity to MAPK inhibitors [abstract]. In: Proceedings of the AACR Conference on Advances in Sarcomas: From Basic Science to Clinical Translation; May 16-19, 2017; Philadelphia, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(2_Suppl):Abstract nr B13.

Subcyclo laser procedure results in patients with glaucoma

Purpose. To analyse the results of subCyclo (subliminal transscleral cyclophotocoagulation) laser procedure for patients with glaucoma. Material and methods. The study included 50 eyes of 32 patients diagnosed with various subtypes of glaucoma for which we performed subliminal transscleral cyclophotocoagulation under retrobulbar anesthesia. After the procedure, all patients were advised to continue their antiglaucoma medication until further notice and we added a topical steroid for 2 weeks. The minimum follow-up period was 6 months. Results. The mean IOP (intraocular pressure) decreased from the preoperative value of 26.27 mmHg (±6.52) to 15.9 mmHg (±5.72) one day after the treatment. At 7 days, the average IOP was 13.72 mmHg (±4.31), 15.81 mmHg (±3.69) at 6 weeks, 15.94 mmHg (±5.66) at 3 months and 16.32 mmHg (±5.24) at 6 months. The second intervention was performed in 9 eyes due to poor IOP control after the first procedure, two eyes developed ocular hypertonia 6-8 hours after the procedure and one eye presented mydriasis after the procedure. Conclusions. Early results for this study showed that subCyclo laser procedure could determine a satisfactory decrease of the IOP with a low risk of complications. Abbreviations: IOP = intraocular pressure, TSCPC = transscleral cyclophotocoagulation, POAG = primary open-angle glaucoma, NVG = neovascular glaucoma, BCVA = best corrected visual acuity.

Abstract 1038: The KIT-V654A second site mutation confers perinatal lethality and increased oncogenesis in a mouse model of GIST

Tyrosine kinase inhibitors have revolutionized the treatment of gastrointestinal stromal tumor (GIST), which are mostly driven by mutations in the receptor tyrosine kinase KIT. However, resistance commonly develops, which is associated with second site mutations in KIT. Here, we created the first genetically engineered mouse model of the most common second site mutation, KIT-V654A (mouse KIT-V653A), to study in vivo its oncogenic properties and mechanisms of resistance in order to develop next-generation GIST therapies.

The knock-in strategy consisted of inserting into the endogenous murine Kit locus a targeting vector containing both the KitV558Δ exon 11 mutation and the KitV653A exon 13 mutation under the control of a floxed neomycin-resistance gene-expression cassette which acts similar to a loxP-STOP-loxP cassette. Treatments included imatinib 45 mg/kg i.p., sunitinib 40 mg/kg p.o., and cabozantinib 60 mg/kg p.o. Tumors were assessed by histology, immunohistochemistry, and western blot.

In contrast to our previously published GIST model with a single mutant KitV558Δ allele, the double knock-in KitV558Δ; V653A-neo allele caused perinatal lethality when activated in pre-implantation embryos with a germline EIIa-Cre approach. We therefore sought to restrict the induction of the KitV558Δ;V653A double mutation to the interstitial cells of Cajal (ICC), the cell of origin of GIST, via the essential ICC lineage survival factor ETV1. The KitV558Δ; V653A-neo/+ mouse was crossed with the Etv1Cre-ERT2/+ mouse expressing Cre recombinase under the Etv1-specific promoter. Systemic administration of tamoxifen at birth in KitV558Δ; V653A-neo/+; Etv1Cre-ERT2/+ mice resulted in cecal GIST development with full penetrance. The tumors were histologically similar to human GIST, stained positive for KIT, and displayed active p-KIT signaling. As expected, high-dose imatinib treatment did not inhibit p-KIT Y719 in these GISTs and did not induce a histologic response. Sunitinib and cabozantinib each had significant anti-tumor effects, as assessed by decreased Ki67 index and increased histologic response. Compared to single mutant KitV558Δ-neo/+; Etv1Cre-ERT2/+ mice, double mutant KitV558Δ; V653A-neo/+; Etv1Cre-ERT2/+ mice developed larger cecal GISTs and had decreased survival.

The KitV558Δ; V653A-neo/+; Etv1Cre-ERT2/+ mouse is the first in vivo model of the most common secondary mutation in GIST and the first in vivo demonstration that cell-autonomous expression of mutant KIT in the ICC lineage gives rise to GIST. We have found cabozantinib, an FDA-approved drug, to be an effective therapy in GISTs harboring the V653A mutation. Furthermore, our results suggest the addition of the KIT-V653A second site mutation leads to increased oncogenesis.

Citation Format: Jennifer Q. Zhang, Benedikt Bosbach, Cristina Antonescu, Peter Besmer, Ronald DeMatteo. The KIT-V654A second site mutation confers perinatal lethality and increased oncogenesis in a mouse model of GIST [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1038. doi:10.1158/1538-7445.AM2017-1038

Combined KIT and CTLA-4 Blockade in Patients with Refractory GIST and Other Advanced Sarcomas: A Phase Ib Study of Dasatinib plus Ipilimumab

Purpose: A phase Ib study of dasatinib plus ipilimumab in patients with gastrointestinal stromal tumor (GIST) and other sarcomas was performed on the basis of preclinical data demonstrating that combined KIT and CTLA-4 blockade is synergistic.Experimental Design: A standard 3 + 3 design was used to evaluate the safety, efficacy, and immune correlates of treatment. Dose escalation cohorts received ipilimumab 10 or 3 mg/kg every 3 weeks, followed by maintenance every 12 weeks with escalating doses of dasatinib (70 mg daily, 100 mg daily, or 70 mg twice daily). Response was assessed by RECIST 1.1, Choi, and immune-related RECIST criteria (irRC).Results: A total of 28 patients (17 male) were enrolled. Histologic subtypes included GISTs (n = 20) and other sarcomas (n = 8.) Dasatinib 70 mg/day with ipilimumab 10 mg/kg or dasatinib 140 mg/day with ipilimumab 3 mg/kg can be safely administered. Dose-limiting toxicities included grade 3 gastric hemorrhage and anemia. No partial or complete responses were noted by RECIST or irRC. There were 7 of 13 partial responses in the GIST patients by Choi criteria, and 3 of 13 patients each had stable and progressive disease, respectively.Conclusions: Dasatinib and ipilimumab can be safely administered to GIST and sarcoma patients. However, dasatinib was not synergistic with ipilimumab, as there was limited clinical efficacy with the combination. This limited cohort provides prospective data that indoleamine-2,3-dioxygenase (IDO) suppression may potentially correlate with antitumor efficacy in GIST. Given the small cohort, it is only hypothesis generating and additional data would be required. In the era of more modern and effective checkpoint inhibitors, next steps could be consideration of tyrosine kinase inhibitors or IDO inhibitors in combination with anti-PD-1 therapy. Clin Cancer Res; 23(12); 2972-80. ©2016 AACR.

Primary Pulmonary Myxoid Sarcoma: A Newly Described Entity-Report of a Case and Review of the Literature

Primary pulmonary myxoid sarcoma (PPMS) is a recently described, exceedingly rare low-grade lung sarcoma that tends to present in young females as an endobronchial mass and shows evidence of an EWSR1- CREB1 fusion. Herein, we present a case of PPMS with fluorescence in situ hybridization (FISH) analysis for EWSR1 and CREB1 rearrangements. An 80-year-old woman presented with an endobronchial, multinodular tumor exhibiting spindle, ovoid and epithelioid cells arranged in reticular/lattice-like and alveolar-like patterns in a myxoid background. The tumor showed focal epithelial membrane antigen immunoreactivity as well as an Alcian blue-positive stroma that was sensitive to digestion with hyaluronidase. EWSR1 and CREB1 rearrangements were detected by break-apart FISH probes. The patient showed persistence of disease 36 months after diagnosis and was discharged to hospice care. We contribute with a report of an additional case of this very unusual entity and perform a brief review of the literature published so far on the subject.

Abstract 1103: Human tumorigenesis induced by endogenous DNA transposase

Recent cancer genome surveys have revealed extremely low rates of coding gene mutations in distinct tumor subtypes, suggesting that alternative mechanisms must contribute to their pathogenesis. Transposons are mobile genetic elements that are found in all living organisms, including humans where they occupy nearly half of the genome. Their mobilization can cause structural rearrangements in normal and cancer cells. However, it remains unknown whether transposition is a cause of cellular transformation or merely a bystander effect of dysregulated gene expression. Here, we report that PGBD5, a recently characterized human gene related to the piggyBac transposase from the cabbage looper moth, is aberrantly expressed in rhabdoid tumors, medulloblastoma, acute leukemias, and some sarcomas and carcinomas. Ectopic expression of PGBD5 in non-transformed primary human cells is sufficient to induce anchorage independence in vitro and penetrant tumor formation in immunodeficient mice in vivo. PGBD5 expression is sufficient to induce genomic mobilization of engineered DNA transposons in human cells, and purified recombinant PGBD5 exhibits transposase domain-dependent endonuclease activity in vitro. Flanking-sequence exponential anchored PCR and massively parallel sequencing of DNA transposon integrations revealed distinct activity on piggyBac-like inverted terminal repeats, and preference for specific euchromatic human genomic loci. This enables mapping of structural rearrangements of endogenous human transposable elements in primary human tumor genomes, some of which target genes involved in cellular transformation. We find that PGBD5 transposase-induced cell transformation is associated with morphologic de-differentiation, induction of distinct Polycomb gene expression programs and structural chromatin remodeling, consistent with its epigenetic control. These findings reveal an unanticipated mechanism of human tumorigenesis, genomic plasticity and structural alterations of non-coding regulatory genomic loci in human cancer.

Citation Format: Anton Henssen, Amy Eisenberg, Eileen Jiang, Elizabeth Henaff, Richard Koche, Melissa Burns, Julianne R. Carson, Gouri Nanjangud, Eric Still, Jorge Gandara, Paolo Cifani, Avantika Dhabaria, Xiaodong Huang, Elisa de Stanchina, Elizabeth Mullen, Hanno Steen, Elizabeth Perlman, Jeffrey Dome, Cristina Antonescu, Cedric Feschotte, Christopher E. Mason, Alex Kentsis. Human tumorigenesis induced by endogenous DNA transposase. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1103. doi:10.1158/1538-7445.AM2015-1103

REFRACTIVE SURGERY FOR HIGH AMETROPIES, A FEW CONCLUSIONS

This paper presents a few clinical cases of patients with high ametropies and/or anisometropia, who underwent one or two surgical procedures in our clinic, in order to obtain independence of glasses or contact lenses. Twenty cases of high ametropies were included in our study, with or without astigmatism, with transparent lenses, who presented in our clinic for surgical treatment to correct their refractive errors. Postoperatively, we analyzed the results and took decisions for each case in particular; sometimes a second surgical procedure was needed.

Abstract 1572: Dystrophin Is a tumor suppressor in human cancers with myogenic programs

Many common human mesenchymal tumors, including gastrointestinal stromal tumor (GIST), rhabdomyosarcoma (RMS), and leiomyosarcoma (LMS), feature myogenic differentiation. Although presumptive initiating mutations have been identified in these cancers, the subsequent mechanisms of malignant progression are not known. Here we report that intragenic deletion of the dystrophin-encoding and muscular dystrophy-associated DMD gene is a frequent mechanism by which myogenic tumors progress to high-grade, lethal sarcomas. Genome-wide SNP screens demonstrated DMD intragenic deletions in 23 of 38 myogenic sarcomas (61%) compared to 0 of 58 non-myogenic sarcomas (p < 0.0001). Although DMD is an X-linked gene, somatic DMD deletions affected both sexes equally and DMD deletions in female patients involved the active X chromosome, resulting in functional DMD nullisomy. Dystrophin was expressed strongly in nonneoplastic and benign counterparts for GIST, RMS and LMS, and the DMD deletions in the malignant myogenic sarcomas clustered at the 5′ end of the gene, inactivating larger dystrophin isoforms, including 427kDa dystrophin, while preserving expression of an essential 71kDa isoform (Dp71) which is encoded by the DMD 3′ end. Dystrophin restoration inhibited myogenic sarcoma cell migration, invasion, anchorage independence, and invadopodia formation, and dystrophin inactivation was found in 96%, 100%, and 62% of metastatic GIST, embryonal RMS, and LMS, respectively. The genomic, clinicopathological and functional evidence validate dystrophin as a tumor suppressor and likely anti-metastatic factor, suggesting that therapies in development for muscular dystrophies may also have relevance in treatment of cancer.

Citation Format: Yuexiang Wang, Adrian Marino-Enriquez, Richard Bennett, Meijun Zhu, Grant Eilers, Cristina Antonescu, Christopher Fletche, Chandrajit Raut, Matt van de Rijn, Louis Kunkel, George Demetri, Jonathan Fletcher. Dystrophin Is a tumor suppressor in human cancers with myogenic programs. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1572. doi:10.1158/1538-7445.AM2014-1572

Why we use AT.Lisa multifocals?

In this paper, the authors try to motivate their preference for implanting AT.Lisa Multifocals from all other premium IOL's from the market. It is emphasized, through clinical examples, that their choice comes after a long experience with this type of mul- tifocals IOL's. We make a short presentation of this particular type of MIOL's with their good but also weak points and try to motivate our decision to change from other types. We present the steps that each patient has to follow in our clinic prior to surgery itself, stressing out the idea that the discussion with the patient is very important in taking a decision regarding the implantation of a Premium IOL.

Round cell sarcomas beyond Ewing: emerging entities

Primitive small blue round cell tumours (SBRCT) of childhood and young adults have been problematic to diagnose and classify. Diagnosis is also complicated in cases with atypical morphology, aberrant immunoprofiles and unusual clinical presentations. Even with the increased use of ancillary techniques in archival material, such as immunohistochemistry and molecular/genetic methods, a proportion of these tumours cannot be subclassified into specific histological types. A subset of tumours resembling microscopically the Ewing sarcoma family of tumours (EFT), being composed of primitive small round cells and occurring in paediatric or young adult age groups, remain unclassified, being negative for EWSR1, SS18(SYT), DDIT3(CHOP) and FOXO1(FKHR) gene rearrangements by FISH/RT-PCR. A small number of cases sharing the undifferentiated EFT appearance have been characterized recently carrying BCOR-CCNB3 or CIC-DUX4 fusions. However, based on the somewhat limited number of cases, it remains unclear if these newly defined genetic entities belong to any of the pre-existing clinicopathological disorders or represent altogether novel conditions. This review presents the latest molecular findings related to these SBRCTs, beyond the common EWSR1-ETS fusions. Specific attention has been paid to morphological features not associated typically with classic EFT, and the value of ancillary tests that can be applied when dealing with EWSR1-negative SBRCTs is discussed.

A broad survey of cathepsin K immunoreactivity in human neoplasms

Cathepsin K is consistently and diffusely expressed in alveolar soft part sarcoma (ASPS) and a subset of translocation renal cell carcinomas (RCCs). However, cathepsin K expression in human neoplasms has not been systematically analyzed. We constructed tissue microarrays (TMA) from a wide variety of human neoplasms, and performed cathepsin K immunohistochemistry (IHC). Only 2.7% of 1,140 carcinomas from various sites exhibited cathepsin K labeling, thus suggesting that among carcinomas, cathepsin K labeling is highly specific for translocation RCC. In contrast to carcinomas, cathepsin K labeling was relatively common (54.6%) in the 414 mesenchymal lesions studied, including granular cell tumor, melanoma, and histiocytic lesions, but not paraganglioma, all of which are in the morphologic differential diagnosis of ASPS. Cathepsin K IHC can be helpful in distinguishing ASPS and translocation RCC from some but not all of the lesions in their differential diagnosis.

A phase II multicenter study of the IGF-1 receptor antibody cixutumumab (A12) and the mTOR inhibitor temsirolimus (TEM) in patients (pts) with refractory IGF-1R positive (+) and negative (-) bone and soft tissue sarcomas (STS)

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Background: Preclinical studies demonstrate synergistic anti-tumor activity by inhibiting mTOR and IGF-1R. This study evaluated the safety and efficacy of A12 and TEM in 3 chemo-refractory cohorts: IGF-1R (+) STS (Arm A), IGF-1R (+) bone (Arm B), and IGF-1R (-) bone and STS (Arm C). Methods: An optimal Simon 2 stage design was used for each arm. The primary end-point was progression free survival (PFS) at 12 weeks. Based on historical data, a 40% PFS rate was considered promising and a 20% PFS non-promising (type I/ II error, 0.05/0.10). ≥5 PFSs at 12 weeks were required in the first 19 and ≥16 PFSs were required in a total of 54 pts to consider each arm positive. Key eligibility: measurable disease (RECIST 1.1), age ≥18, 1- 4 priors, ECOG status 0-1. A12 (6 mg/kg) and TEM (25 mg) were administered IV weekly. Pre and post treatment tumor biopsies and plasma for IGF-1 and IGFBP3 were obtained. 20 Sarcoma Centers participated. Results: Starting in 02/2010, 383 pts were tested for IGF-1R by immunohistochemistry (IHC; 54% +) and 171 were treated: mean age 47 (range: 18-80), mean # priors 2.2 (range: 1-4). Grade 3/4 toxicities ≥10%: lymphopenia (12%), mucositis (10%). By intent to treat (ITT) analysis, each arm of the study achieved its primary 12 week PFS end-point (≥16 PFSs): Arm A: 18/56 (32%), Arm B: 19/50 (38%) (4 too early), Arm C: 27/63 (43%). The one-sided 95% CI for 12-week PFS is (0.22, 1), (0.27, 1), and (0.32, 1), respectively. By ITT the median PFS (95% CI) in weeks for each arm is 6.3 (5.9, 12.0), 11.0 (8.0, 18.0) and 11.6 (9.0, 17.9), respectively, and for chondro (n=18), Ewing’s (n=24), and osteo (n=23) only it is 22.6 (5.7, 40.9), 10.4 (5.7, 17.9) and 6.0 (6.0, 18.0), respectively. Westerns on 32 matched pair tumor biopsies indicate inhibition of IGF-1R, pAKT and pS6. Of biopsies on 7 IGF-1R (-) IHC pts (Arm C), 5 were IGF-1R (+) by western. Plasma biomarkers did not correlate with PFS. Conclusions: A12 and TEM met its primary end-point of improved PFS in pts with metastatic sarcoma. This effect was independent of IGF-1R status by IHC. These results support further clinical development of this combination in bone and STS.

Phase II trial of the CDK4 inhibitor PD0332991 in CDK4-amplified liposarcoma

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Background: CDK4 is amplified in approximately 90% of well-differentiated/de-differentiated liposarcomas (WD/DDLS). The selective CDK4/CDK6 inhibitor PD0332991 (PD) inhibits growth and induces senescence in liposarcoma cell lines and xenografts. In a phase I trial of PD, several patients with progressive WD/DDLS had prolonged stable disease for several years. To determine the safety and efficacy of PD, a phase II study was performed. Methods: Participants were patients with advanced WD/DDLS. Eligibility criteria were age≥18 years, measurable WD/DDLS (RECIST 1.1), documented progression on at least one systemic therapy directly before enrollment, CDK4 amplification by fluorescence in situ hybridization and retinoblastoma protein (RB) expression by immunohistochemistry (≥1+). Pts received oral PD 200mg daily for 14 consecutive days in 21-day cycles. The primary endpoint was progression-free survival (PFS) at 12 weeks. Based on historical data, a promising result was defined as a 12-week PFS of ≥40% and not promising as ≤20%. The sample size was up to 28 evaluable patients. If 9 patients were progression free at 12 weeks, then PD would be considered to have activity in WD/DDLS. Results: Of 44 patients screened (42/44 CDK4 amplified; 41/44 RB+), 29 were enrolled and 27 were evaluable for the primary endpoint. Median age was 65 (range 37-83); 52% were male; ECOG scores were 0 (69%) or 1 (31%), and the median number of prior regimens was 1 (range 1-5). PFS at 12 weeks was 70% (19/27 patients; 90% CI 56-100%), and thus the study significantly exceeded its primary endpoint. At the data cutoff, the median PFS was 18 weeks. Seven patients remain on study with stable disease at 18-48 weeks of followup. Grade 3 and 4 events included anemia (grade 3, 14%), thrombocytopenia (grade 3, 17%; grade 4, 14%), neutropenia (grade 3, 41%; grade 4, 7%) and febrile neutropenia (3%). Dose reductions were required in 24% of patients. Conclusions: Among patients with WD/DDLS with CDK4 amplification and RB expression who had actively progressing disease despite prior systemic therapy, treatment with the CDK4 inhibitor PD0332991 was associated with improved PFS. A randomized phase 3 trial is planned.

Restoration of C/EBPα in dedifferentiated liposarcoma induces G2/M cell cycle arrest and apoptosis

Well-differentiated liposarcoma (WDLS) and dedifferentiated liposarcoma (DDLS) represent the most common biological group of liposarcoma, and there is a pressing need to develop targeted therapies for patients with advanced disease. To identify potential therapeutic targets, we sought to identify differences in the adipogenic pathways between DDLS, WDLS, and normal adipose tissue. In a microarray analysis of DDLS (n = 84), WDLS (n = 79), and normal fat (n = 23), C/EBPα, a transcription factor involved in cell cycle regulation and differentiation, was underexpressed in DDLS when compared to both WDLS and normal fat (15.2- and 27.8-fold, respectively). In normal adipose-derived stem cells, C/EBPα expression was strongly induced when cells were cultured in differentiation media, but in three DDLS cell lines, this induction was nearly absent. We restored C/EBPα expression in one of the cell lines (DDLS8817) by transfection of an inducible C/EBPα expression vector. Inducing C/EBPα expression reduced proliferation and caused cells to accumulate in G2/M. Under differentiation conditions, the cell proliferation was reduced further, and 66% of the DDLS cells containing the inducible C/EBPα expression vector underwent apoptosis as demonstrated by annexin V staining. These cells in differentiation conditions expressed early adipocyte-specific mRNAs such as LPL and FABP4, but they failed to accumulate intracellular lipid droplets, a characteristic of mature adipocytes. These results demonstrate that loss of C/EBPα is an important factor in suppressing apoptosis and maintaining the dedifferentiated state in DDLS. Restoring C/EBPα may be a useful therapeutic approach for DDLS.

Comparison of doxorubicin and weekly paclitaxel efficacy in metastatic angiosarcomas

BACKGROUND

Data regarding the role of anthracyclines and taxanes as first-line treatments of metastatic angiosarcoma are limited.

METHODS

Records of 117 metastatic angiosarcoma patients who were treated with either doxorubicin or weekly paclitaxel were reviewed.

RESULTS

Seventy-five patients (64%) were treated with weekly paclitaxel and 42 (36%) with single-agent doxorubicin. Patients in the weekly paclitaxel group were older and more frequently had angiosarcomas arising from the skin. In the doxorubicin group, 34 patients were evaluable for response: 2 (6%) had complete response, 8 (23.5%) had partial response, 10 (29.5%) had stable disease, and 14 (41%) had progressive disease. In the weekly paclitaxel group, 68 patients were evaluable for response: 9 (13%) had complete response, 27 (40%) had partial response, 20 (29.5%) had stable disease, and 12 (17.5%) had progressive disease. Objective responses to weekly paclitaxel were more frequent in cutaneous angiosarcomas, whereas tumor location did not impact response to doxorubicin. Median progression-free survival (PFS) was 4.9 months (95% confidence interval [95% CI], 3.9-6.0 months). Median overall survival (OS) was 8.5 months (95% CI, 6.4-10.7 months). On multivariate analysis, ECOG performance status (PS) was the sole independent factor associated with PFS and OS.

CONCLUSIONS

First-line single-agent doxorubicin and weekly paclitaxel seem to have similar efficacy in metastatic angiosarcomas. Cutaneous angiosarcomas respond favorably to weekly paclitaxel. Best supportive care should be considered in patients with poor PS.

Confirmed angiosarcoma: prognostic factors and outcome in 50 prospectively followed patients

Purpose. Angiosarcoma is a rare tumor with endothelial cell differentiation that may arise in any anatomic location.The purpose of this report was to identify prognostic factors on outcome in a group of prospectively followed patients with confirmed angiosarcoma.Subjects. Adult patients (>16 years old) with angiosarcoma treated between July 1982 and February 1998 were identified from a prospective database.Methods. Pathologic confirmation of all cases was performed prior to inclusion in this analysis. Various prognostic factors were evaluated for disease-specific survival. Survival was determined by the Kaplan- Meier method. Statistical significance was evaluated by log-rank test for univariate analysis and Cox stepwise regression for multivariate analysis (p<0.05).Results. Fifty patients were identified; at the initial evaluation, this group included 32 patients with a primary tumor, three with local recurrence and 15 with metastatic disease. Tumor sites included 16 head and neck and skin of head, eight extremity, seven trunk, six breast, five pelvis, four viscera and four thoracic. Median follow-up among survivors was 71 months (range, 38-191 months).Two- and 5-year disease-specific survival was 50 and 30%, respectively, with a median of 24 months. The factor predictive of tumor-related mortality was presentation status (p=0.001; relative risk, 5). Two-year disease-specific survival for patients presenting with recurrent or metastatic disease was 13%, compared with 70% for those with primary disease.

Expression profiling of liposarcoma yields a multigene predictor of patient outcome and identifies genes that contribute to liposarcomagenesis

Liposarcomas are the most common type of soft tissue sarcoma but their genetics are poorly defined. To identify genes that contribute to liposarcomagenesis and serve as prognostic candidates, we undertook expression profiling of 140 primary liposarcoma samples, which were randomly split into training set (n = 95) and test set (n = 45). A multigene predictor for distant recurrence-free survival (DRFS) was developed by the supervised principal component method. Expression levels of the 588 genes in the predictor were used to calculate a risk score for each patient. In validation of the predictor in the test set, patients with low risk score had a 3-year DRFS of 83% versus 45% for high risk score patients (P = 0.001). The HR for high versus low score, adjusted for histologic subtype, was 4.42 (95% CI, 1.26-15.55; P = 0.021). The concordance probability for risk score was 0.732. In contrast, the concordance probability for histologic subtype, which had been considered the best predictor of outcome in liposarcoma, was 0.669. Genes related to adipogenesis, DNA replication, mitosis, and spindle assembly checkpoint control were all highly represented in the multigene predictor. Three genes from the predictor, TOP2A, PTK7, and CHEK1, were found to be overexpressed in liposarcoma samples of all five subtypes and in liposarcoma cell lines. RNAi-mediated knockdown of these genes in liposarcoma cell lines reduced proliferation and invasiveness and increased apoptosis. Taken together, our findings identify genes that seem to be involved in liposarcomagenesis and have promise as therapeutic targets, and support the use of this multigene predictor to improve risk stratification for individual patients with liposarcoma.

Final results of a University of Chicago phase II consortium trial of sorafenib (SOR) in patients (pts) with imatinib (IM)- and sunitinib (SU)-resistant (RES) gastrointestinal stromal tumors (GIST)

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Background: GIST pts who develop resistance to IM and SU have few therapeutic options. SOR inhibits KIT, VEGFR, PDGFR-β, and BRAF kinases. In preclinical models, SOR has activity against several IM-RES mutations that are resistant to SU (Heinrich. ASCO 2009).

Methods: We performed a multi-center, phase II trial of SOR in unresectable, KIT-expressing GIST pts who had disease progression on IM by RECIST. After FDA approval of SU for IM-RES GIST, the study was amended in 2/07 to require progression after both IM and SU. Pts received SOR 400 mg orally twice daily. CT scans were obtained Q2 28-day cycles. The primary endpoint was objective response rate. A Simon minimax 2-stage design required 1 response in 18 pts to proceed to a second stage, and 4 responses in 32 IM/SU RES pts for further investigation.

Results: 38 pts (6 IM-RES, 32 IM/SU-RES) enrolled 1/06-9/09 at 6 centers. Median follow-up for survivors: 31 months (mo). Pt characteristics: male 55%; median age 57 (range 42-85); PS 0/1/2: 47%/47%/6%. Median cycles: 4 (range 1-37). 63% pts had at least 1 dose reduction. Partial response (PR): 13% (1 IM-RES, 4 IM/SU-RES); stable disease (SD): 55% (3 IM-RES, 18 IM/SU-RES). Disease control rate (PR + SD): 68%. Median progression-free survival: 5.2 mo (95% CI: 3.4, 7.4). Median overall survival 11.6 mo (95% CI: 8.8, 18.0); 1-year survival 50%; 2-year survival 29%. Three pts remain on trial receiving study drug (1 PR at 34 mo; 2 SD at 18 and 37 mo). Grade 3/4 toxicities (% pts): hand-foot syndrome 45%, hypertension 21%, diarrhea 8%, hypophosphatemia 8%, GI bleed 5%, rash 5%, thrombosis 3%, GI perforation 3%, fatigue 3%, anemia 3%.

Conclusions: SOR is active in IM-and SU-resistant GIST. Some pts treated with SOR experience prolonged disease control. SOR is well-tolerated in GIST pts, but dose reductions are often required. SOR warrants further investigation in GIST. Supported by NCI grant N01-CM-62201.

[Table: see text]

ZIC1 overexpression is oncogenic in liposarcoma

Liposarcomas are aggressive mesenchymal cancers with poor outcomes that exhibit remarkable histologic diversity (there are five recognized subtypes). Currently, the mainstay of therapy for liposarcoma is surgical excision because liposarcomas are often resistant to traditional chemotherapy. In light of the high mortality associated with liposarcoma and the lack of effective systemic therapy, we sought novel genomic alterations driving liposarcomagenesis that might serve as therapeutic targets. ZIC1, a critical transcription factor for neuronal development, is overexpressed in all five subtypes of liposarcoma compared with normal fat, and in liposarcoma cell lines compared with adipose-derived stem cells. Here, we show that ZIC1 contributes to the pathogenesis of liposarcoma. ZIC1 knockdown inhibits proliferation, reduces invasion, and induces apoptosis in dedifferentiated and myxoid/round cell liposarcoma cell lines, but not in either adipose-derived stem cells or in a lung cancer cell line with low ZIC1 expression. ZIC1 knockdown is associated with increased nuclear expression of p27 proteins and the downregulation of prosurvival target genes BCL2L13, JunD, Fam57A, and EIF3M. Our results show that ZIC1 expression is essential for liposarcomagenesis and that targeting ZIC1 or its downstream targets might lead to novel therapy for liposarcoma.

Combination of PI3K/mTOR inhibition demonstrates efficacy in human chordoma

BACKGROUND

Chordomas are rare tumors of the axial skeleton for which surgical resection remains the most reliable means of cure. PI-103 is a inhibitor of PI3K/AKT and mTOR activation. This study aims to determine whether the PI3K/mTOR pathway was active in chordomas and whether their inhibition could lead to decreased proliferation and increased apoptosis.

MATERIALS AND METHODS

Thirteen human chordoma were tested for activation of the PI3K/mTOR pathway. The human chordoma cell line UCH-1 was treated with increasing doses of PI-103. Inhibition of AKT and mTOR was examined and assays assessing proliferation and apoptosis were performed.

RESULTS

The chordoma specimen demonstrated activation of the PI3K/mTOR pathway. PI-103 inhibited the AKT and mTOR activation in the UCH-1 cell line. PI-103 inhibited proliferation and induced apoptosis in UCH-1.

CONCLUSION

The PI3K/AKT and mTOR signaling pathway is constitutively activated in chordoma. PI-103 decreases proliferation and induces apoptosis in the UCH-1 via inhibition of the PI3K/mTOR pathway.

Regulation of glucose transporter 4 traffic by energy deprivation from mitochondrial compromise

Skeletal muscle is the major store and consumer of fatty acids and glucose. Glucose enters muscle through glucose transporter 4 (GLUT4). Upon insufficient oxygen availability or energy compromise, aerobic metabolism of glucose and fatty aids cannot proceed, and muscle cells rely on anaerobic metabolism of glucose to restore cellular energy status. An increase in glucose uptake into muscle is a key response to stimuli requiring rapid energy supply. This chapter analyses the mechanisms of the adaptive regulation of glucose transport that rescue muscle cells from mitochondrial uncoupling. Under these conditions, the initial drop in ATP recovers rapidly, through a compensatory increase in glucose uptake. This adaptive response involves AMPK activation by the initial ATP drop, which elevates cell surface GLUT4 and glucose uptake. The gain in surface GLUT4 involves different signals and routes of intracellular traffic compared with those engaged by insulin. The hormone increases GLUT4 exocytosis through phosphatidylinositol 3-kinase and Akt, whereas energy stress retards GLUT4 endocytosis through AMPK and calcium inputs. Given that energy stress is a component of muscle contraction, and that contraction activates AMPK and raises cytosolic calcium, we hypothesize that the increase in glucose uptake during contraction may also involve a reduction in GLUT4 endocytosis.

Clinicopathologic profile of gastrointestinal stromal tumors (GISTs) with primary KIT exon 13 or exon 17 mutations: a multicenter study on 54 cases

Gastrointestinal stromal tumors (GISTs) are mesenchymal neoplasms driven by oncogenic, mutational activation of KIT or platelet-derived growth factor receptor alpha (PDGFRA). GIST-specific KIT or PDGFRA mutations have been linked to tumor location, tumor cell morphology and clinical behavior. The purpose of this study was to evaluate the clinicopathologic profile of GISTs that have KIT exon 13 or exon 17 mutations. Through the collaboration of several GIST research groups, we gathered 54 cases from the pre-imatinib era that had such primary mutations. From our observations and those in the literature, we estimate that the frequency of these mutations is no higher than 1-2%. Almost all (32 of 33, 97%) of the KIT exon 13 mutations were the 1945A>G substitution leading to Lys642Glu. A majority (15 of 21, 71.4%) of the KIT exon 17 mutations were the 2487T>A substitution leading to Asn822Lys. Demographic and clinicopathologic data were available for 26 and 14 KIT exon 13 and exon 17 mutant GISTs, respectively. Median age and male to female ratio were similar to ones reported in other GIST studies. Small intestinal tumors were two times more frequent than gastric ones among KIT exon 17 mutants. Also, intestinal tumors were slightly overrepresented among KIT exon 13 mutants when compared with population-based studies. The majority of KIT exon 13 or exon 17 mutants had a spindle-cell morphology and only a few had epithelioid features. Tumor size varied from 1.2 to 25 cm and average mitotic rates were 9.5 and 4.2 for KIT exon 13 and exon 17 mutants, respectively. Gastric KIT exon 13 mutant GISTs tend to be slightly larger and more aggressive than gastric GISTs in average, whereas the behavior of small intestinal GISTs with KIT exon 13 mutations does not differ from other small intestinal GISTs. The latter is also true for all KIT exon 17 mutant GISTs.

Spinal metastases from myxoid liposarcoma warrant screening with magnetic resonance imaging

BACKGROUND

Myxoid liposarcoma (MLS) has an unusual tendency for extrapulmonary metastasis, particularly to the spine and soft tissues. The objective of this study was to determine the prevalence of spinal metastasis, treatment outcomes, and optimal screening method for spinal metastasis in patients with MLS.

METHODS

Data from patients with had spinal metastases were obtained from the authors' institutional soft tissue sarcoma database. The accuracy with which positron emission tomography (PET) scans and bone scans identified metastatic lesions was compared with the accuracy of magnetic resonance imaging (MRI). Clinical response to treatment was based on pain, neurologic scores, and survivorship analysis.

RESULTS

There were 33 patients who developed spinal metastasis after a median 36 months of follow-up (range, from 7.5 months to 33 years). Known spinal metastases were detected by bone scans in 16% of patients and by PET scans in 14% of patients. Patients who underwent surgery had high-grade spinal cord compression more often than patients who did not undergo surgery (72% vs 19%, respectively; P = .002). Pain and neurologic function were improved or maintained in all patients who received radiation alone (n = 8 patients) and in all but 1 patient who underwent surgery (n = 18 patients). The median overall survival was 51.4 months from the time of primary diagnosis and 21.9 months from the time of first metastasis.

CONCLUSIONS

Bone scans and PET scan lack sufficient sensitivity to detect spinal metastasis from MLS. Treatment of metastasis is palliative, but local treatment can yield long-term disease control in select patients. Screening with whole-spine MRI may lead to the earlier detection of spinal metastasis.

Histone H2AX is a mediator of gastrointestinal stromal tumor cell apoptosis following treatment with imatinib mesylate

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract and are caused by activating mutations of the KIT or platelet-derived growth factor receptor alpha (PDGFRA) tyrosine kinases. GISTs can be successfully treated with imatinib mesylate, a selective small-molecule protein kinase inhibitor that was first clinically approved to target the oncogenic BCR-ABL fusion protein kinase in chronic myelogenous leukemia, but which also potently inhibits KIT and PDGFR family members. The mechanistic events by which KIT/PDGFRA kinase inhibition leads to clinical responses in GIST patients are not known in detail. We report here that imatinib triggers GIST cell apoptosis in part through the up-regulation of soluble histone H2AX, a core histone H2A variant. We found that untreated GIST cells down-regulate H2AX in a pathway that involves KIT, phosphoinositide-3-kinase, and the ubiquitin/proteasome machinery, and that the imatinib-mediated H2AX up-regulation correlates with imatinib sensitivity. Depletion of H2AX attenuated the apoptotic response of GIST cells to imatinib. Soluble H2AX was found to sensitize GIST cells to apoptosis by aberrant chromatin aggregation and a transcriptional block. Our results underscore the importance of H2AX as a human tumor suppressor protein, provide mechanistic insights into imatinib-induced tumor cell apoptosis and establish H2AX as a novel target in cancer therapy.

Wide Expression and Cellular Localization of Inflammation-associated TSG-6 Protein in Atherosclerotic Lesions (100.17)

TNF-stimulated gene 6 (TSG-6) is induced by TNF-α during inflammation and its secreted product TSG-6 glycoprotein is involved in immune-mediated inflammatory diseases and fertility. It regulates COX-2 and prostaglandin synthesis, and participates in extracellular matrix remodeling. Considering the chronic inflammatory nature of atherosclerosis we hypothesized that TSG-6 is expressed in atherosclerotic plaques and investigated TSG-6 protein expression and cellular distribution on 12 superficial femoral artery endarterectomy specimens from 6 diabetic and 6 non-diabetic patients with peripheral vascular disease. Six histologically normal radial artery specimens were analyzed as control. Paraffin embedded samples were studied by immunohistochemistry using a goat polyclonal anti-human-TSG-6 antibody. TSG-6 expression was consistently present in all atherectomy specimens but not in control specimens. A distinct, strong cytoplasmic staining pattern was uniformly detected in the endothelial lining of the intima, as well as in the neo-vessel proliferation of the plaque. Cytoplasmic staining was also identified in the smooth muscle cell proliferation of the neo-intima. Patchy TSG-6 expression was noted in the extracellular matrix. Within the inflammatory plaques from diabetic patients, TSG-6 stained the foamy macrophages. Our study identifies for the first time the preferential expression of TSG-6 in atherosclerotic lesions and characterizes its distribution within the cellular and matrix components of the plaque. TSG-6 is a novel inflammatory mediator of atherosclerosis and a potentially new marker of endothelial / smooth muscle cell activation.

Adult genitourinary sarcoma: the 25-year Memorial Sloan-Kettering experience

PURPOSE

Urological sarcomas are rare. We describe a continued single institutional experience during 25 years.

MATERIALS AND METHODS

The records from July 1977 to July 2003 were reviewed of all patients at our institution with sarcoma arising in the urinary tract or male genital system who were 16 years or older at diagnosis.

RESULTS

The primary tumor site in 131 patients was the bladder in 20, the kidney in 26, paratesticular in 57, the prostate in 21 and other in 7. Median followup was 4.0 years. The most common histological subtypes were leiomyosarcoma in 29% of cases and liposarcoma in 26%. Median tumor size was 7 cm and 78% of lesions were high grade. Of the patients 28 (21%) presented with metastatic disease and their median survival was 1.4 years compared to 10.7 years in patients without metastatic disease (p < 0.0001). Disease specific survival was 56% and 42% at 5 and 10 years, respectively and median survival was 7.6 years. On univariate analysis unfavorable prognostic variables for disease specific survival were metastasis at presentation, high tumor grade, a lack of leiomyosarcoma and liposarcoma histological subtypes, prostate sarcoma and large tumor size, incomplete surgical resection and positive surgical margin. Patient sex, age and surgical margin status were not significant predictors. On multivariate analysis 2 variables remained significant predictors of disease specific survival, including tumor size (HR 1.1, 95% CI 1.02 to 1.17) and absent metastasis at diagnosis (HR 4.9, 95% CI 1.4 to 17.2).

CONCLUSIONS

Predictors of disease specific survival include local disease at presentation, complete tumor resection and tumor grade, size, location and histological subtype. With adequate surgical treatment most patients who presented with primary disease and underwent complete surgical resection achieved prolonged disease specific survival.