AFAP1L1 is strongly associated with malignant osteosarcoma, liposarcoma, and leiomyosarcoma, it localizes to invadopodia and controls cell invasion by a novel Lyn/AFAP1L1/Vav2-Nck2 pathway

Background: Sarcoma is a malignant cancer that arises from transformed cells of mesenchymal origin. Sarcoma has the characteristics of low incidence and wide distribution of onset age. Sarcoma patients have poor prognosis and very limited selection of approved targeted drugs. Till now, the genomic features of sarcoma patients in China have not been well understood. Here we present the comprehensive genomic features of 202 sarcoma patients and compared mutations in different subtypes of sarcomas. Methods: Deep sequencing targeting 450 cancer genes was performed on FFPE and matched blood samples collected from 202 sarcoma patients. Based on the histology patients included 33 osteosarcoma (OS), 24 rhabdomyosarcoma (RMS), 20 liposarcoma (LPS), 19 fibrosarcoma (FBS), 16 leiomyosarcoma (LMS), 14 Ewing’s sarcoma (ES), 11 hemangiosarcoma (HMS), 10 synovial sarcoma (SS), 9 chondrosarcoma (CDS), and 46 others in this study. Genomic alterations (GAs) including single nucleotide variants (SNVs), insertions and deletions, copy number variations (CNV) and fusions were assessed. Results: Based on the deep sequencing results, there are 1219 somatic mutations detected in all 202 sarcomas, average 6.0 mutations per sample. The most common GAs of LPS, ES and SS’s are consistent with those mentioned in NCCN guidelines (MDM2 55%, EWSR1 78.6% and SS18 80%, respectively). OS, RMS and LMS shared the same most common GAs of TP53 (25%-50%). The second ranked common GAs were NCOR1 (24%), FRS2 (20.8%), ATRX (25%) genes, and the third ranked GAs were RB1 (24%), CDK4 (16.7%) and MAP2K4 (25%) genes. 161/202 patients (79.7%) harbored at least one actionable mutations which might benefit from FDA approved drugs or drugs were under investigation in clinical trials. All FBS, 93.8% LMS and 90.9% HMS have actionable mutations, however, only 10% SS and 35.7% ES have actionable mutations. 8 samples have CNV (including MDM2/4, EGFR and CCND1) which was related to hyper-progression of immunotherapy. All these 8 samples were bone tumor including 4 OS, 1 CDS, 2 ES and 1 fibrosarcoma of bone. Conclusions: Through the comprehensive genomic profiling, different types of sarcomas showed different characteristics of genomic alterations, and potential therapeutic targets may be identified for the patients. Further, NGS provides information on whether or not patients may have the potential hyper-progression of immunotherapy. Citation Format: Xinghua Song, Zuping Lian, YanBin Xiao, Kunpeng Bu, Ye Qiu, Tao Ji, Dan Liu, Angen Liu, Kai Wang. Comparison of mutations in different subtypes of sarcomas and its clinical implications [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3421.

Eribulin-based treatment in patients affected by sarcomas: a case series.

Background: Leucine rich repeat containing 15 (LRRC15) is a TGFβ-regulated structural protein that is highly expressed on cancer-associated fibroblasts (CAFs) in the stromal microenvironment of many solid tumors, as well as directly on cancer cells of mesenchymal origin. Soft tissue sarcomas (STS) and bone sarcomas (BS) represent a diverse family of mesenchymal malignancies that can develop at any anatomic site and that comprise more than 70 histopathologic subtypes. After screening LRRC15 expression across a variety of sarcoma histologies, we evaluated the antitumor activity of ABBV-085, an MMAE (monomethyl auristatin E) containing antibody-drug conjugate directed against LRRC15 (mouse, cyno, human), in patient-derived xenograft (PDX) models of selected sarcomas with varying levels of LRRC15 expression. Methods: LRRC15 expression/intensity in sarcoma histologies was performed by immunohistochemical (IHC) staining (Leica Bond RX, Bond Polymer Refine Kit) with a human LRRC15 specific mouse IgG2b antibody. Based on LRRC15 expression levels, STS and BS tumor fragments (PDXs) were implanted into NSG mice. Mice with growing tumors were then selected to evaluate the in vivo efficacy of ABBV-085 monotherapy (6 mg/kg). Results: LRRC15 expression was evaluated in 340 human sarcoma tumors representing a variety of STS and BS histologic subtypes. LRRC15 IHC expression was determined by scoring the percentage of positive cells, together with the intensity of staining (score of 0 for negative, 1 for weak, 2 for moderate, and 3 for strong staining), for the cancer cells and stroma, respectively. A stringent cut-off for strong LRRC15 positivity was defined as ≥2+ intensity in ≥50% of the cancer or stromal area. Strong LRRC15 expression was observed in several sarcoma subsets: 67% (14/21) of osteosarcoma (OS) tumor samples, 64% (23/36) of undifferentiated pleomorphic sarcoma (UPS), 18% (8/44) of leiomyosarcomas (LMS) and 17% (6/35) of liposarcomas (LPS). Significant antitumor activity including regressions and cures was induced by ABBV-085 in LRRC15-positive STS and BM PDX models, when compared with isotype-control treated mice. The ABBV-085-induced efficacy in osteosarcoma PDX models was superior to current standard-of-care therapies when dosed maximally in mice. In addition, ABBV-085 demonstrated efficacy in different LRRC15 positive STS subtypes including UPS, LMS and LPS. ABBV-085 was well tolerated with minimal to no body weight loss observed. Conclusions: LRRC15 is highly expressed in the majority of human osteosarcomas and undifferentiated pleomorphic sarcomas, as well as in a range of other STS and BS subtypes. ABBV-085 demonstrates promising preclinical antitumor efficacy in LRRC15-positive PDX models of STS and BS. ABBV-085 is currently being investigated in an ongoing phase 1 study in soft tissue sarcomas (including undifferentiated pleomorphic sarcoma) and osteosarcoma. Citation Format: Eytan Ben-Ami, Ying Huang, Prafulla C. Gokhale, Benjamin Eschle, Lisa Durkin, Jonathan Hickson, Mien Sho, Susan Morgan-Lappe, Kurt Gish, Dominic W. Lai, Randy R. Robinson, Diane Hollenbaugh, Eric D. Hsi, Debra T. Chao, George D. Demetri, James W. Purcell. LRRC15 is a novel antigen in sarcoma and the therapeutic target of the antibody-drug conjugate (ADC) ABBV-085 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 953.

Immune checkpoint proteins, such as PD-L1 and PD-1, are important in several cancers; however, their role in osteosarcoma (OSA) and soft tissue sarcoma (STS) remains unclear. Our aims were to determine whether subsets of OSA/STS harbor tumor-infiltrating lymphocytes (TILs) and express PD-L1, and how PD-L1 expression is related to clinical outcome. Tissue sections of 25 cases each of untreated undifferentiated pleomorphic sarcoma (UPS), myxofibrosarcoma (MFS), liposarcoma (LPS) and 24 of leiomyosarcoma (LMS) were subjected to immunohistochemistry (IHC) for immune cells, PD-L1 and PD-1. RT-qPCR was utilized to quantify levels of PD-L1 mRNA from 33 UPS, 57 MFS and 79 OSA primary-untreated specimens. PD-L1 mRNA levels were tested for their correlation with overall survival in patients presenting without metastases. Transcriptome analysis evaluated biological pathway differences between high and low PD-L1 expressers. A subset of UPS and MFS contained TILs and expressed PD-L1 and PD-1; LMS and LPS did not. PD-L1 levels by IHC and RT-qPCR were positively correlated. PD-L1 over-expression was associated with better survival for UPS and OSA, but not MFS. The Th1 pathway was significantly activated in UPS with high levels of PD-L1 and improved survival. Some sarcoma subtypes harbor TILs and express PD-L1. Patients with UPS and OSA with high levels of PD-L1 had better overall survival than those with low expression levels. Important biological pathways distinguish PD-L1 high and low groups. The stratification of patients with OSA/STS with respect to potential immune therapies may be improved through investigation of the expression of immune cells and checkpoint proteins.

11575 Background: To further explore the activity of T as second/further line treatment in retroperitoneal leiomyosarcoma (LMS) and well differentiated/dedifferentiated liposarcoma (LPS). The primary endpoint of the study was the growth modulation rate (GMR) defined as the ratio between the time to progression under T (TTP) and during previous chemotherapy treatment (TTP-1). The secondary end-points were objective response rate as per RECIST and PFS. Methods: This was a multicenter, single-arm Phase 2 study, conducted in 20 Italian centers. Patients with locally relapsed or metastatic disease, already treated with one or more previous systemic treatments with anthracyclines and/or ifosfamide, were enrolled. T was administered at a dose of 1.3-1.5 mg/mq with a top dose of 2.6 mg per cycle. T was administered as a 24h continuous infusion until progressive disease, major toxicity, patient’s intolerance or medical decision. As per protocol, patients were considered responders if the GMR was > 1.33, non-responders if < 0.75 and neither if 0.76-1.32. Eighty evaluable patients were needed to detect an odds of trabectedin response ≥ 2.5, corresponding to 71.4% of patients with a GMR > 1.33 (80% power, one-sided alpha 2.5%). Results: From August 2014 to February 2019, 104 patients were registered and 91 were evaluable for the primary endpoint (32 pts with LMS and 59 with LPS). Overall, the median number of cycles received was 6.0 (q1-q3 3.0-12.0), the main reason for treatment discontinuation was disease progression in 72% of patients, followed by medical decision (8%). The median TTP was 6.0 months (6.2 and 6.0 for LMS and LPS), while the median TTP-1 was 7.5 months (8.1 and 6.4 for LMS and LPS). Thirty three patients (52% 95%CI: 36-58, p = 0.674, odds of response = 1.1) had a GMR > 1.33 (LMS: 46%, 95%CI 26-67,odds = 0.85; LPS 56%, 95%CI 40-72, odds = 1.3).Overall, response rate (CR+PR) was 16% (24% for LMS and 12% for LPS). Overall, in LPS we observed 15/47 patients with GMR < 0.5 and 15/47 with GMR > 2. Among LMS patients, 9/26 had a GMR < 0.5 and 10/26 > 2. Between LPS six patients had a GMR > 5. Previous treatment had been based on anthracyclines and/or ifosfamide in 85% of patients (91% in LPS population). Conclusions: While the primary end point of the study was not met, we noticed a subgroup of patients with a markedly discrepant TTP with T in comparison to previous therapy (GMR < 0.5 or > 2, the latter including some pts with a long TTP with T). Efforts are ongoing to assess the pathologic counterparts of such discrepancies. T seems to be selectively active in poorly understood subgroups, with a pattern of activity distinct from other available agents. Clinical trial information: 2012-005428-14.

Purpose. Colorectal sarcomas are rare and their treatment remains controversial. This study describes the clinical features of colorectal sarcoma. Methods. Data were obtained from a retrospective database of all colorectal malignancies at Taipei Veterans General Hospital. From 1998-2008, 873 sarcoma cases and 5594 colorectal malignant tumors were diagnosed. Eleven patients with colorectal sarcoma were identified. Results. The 11 patients (five males, six females, mean age of 61.7 years) presented primary tumors in the rectum (n=7) and colon (n=4). Surgical intervention in 10 patients (one patient was initially diagnosed with lung metastasis and did not undergo surgical intervention) was uneventful. The mean tumor size was 9.6 cm (range, 4-30 cm). Histological findings were leiomyosarcoma in seven cases and sarcomatoid carcinoma, liposarcoma, synovial sarcoma and embryonal rhabdomyosarcoma each in one case. Five of the seven leiomyosarcoma patients (71.4%) developed recurrences during the follow-up period. Recurrence sites included local recurrence (n=2) and liver metastasis (n=3). The overall and disease-free survival periods of the leiomyosarcoma patients were 52.8 months and 44.7 months, respectively. Conclusions. In our experience, sarcoma is a rare tumor in colorectal neoplasm and leiomyosarcoma is the most common histological type. Despite radical surgical intervention and no lymph node metastasis at time of treatment, leiomyosarcoma has a high recurrence rate. The absences of a reliable tumor marker and useful adjuvant chemotherapy make close image follow-up mandatory in the disease management.

An unusual intracranial metastasis of osteosarcoma.

Objective To explore the effects of extremity salvage surgery of osteosarcoma in children of different ages. Methods A total of 57 children aged under 11 years with malignant osteosarcoma from June 2008 to June 2011 were selected into children group. And 38 cases underwent biological reconstruction while another 19 cases received prosthesis. For control group, 60 adolescent patients aged above 12 years with malignant bone tumors during the same period were designated as control group. And 42 cases had biological reconstruction while 18 cases received prosthesis. The postoperative survival rates of three groups were observed. And the optimal extremity salvage surgery was summarized with statistical processing. Results During follow-ups, the mortality rate was 33.3%. And 1, 2, 3 and 5-year survival rates were (86.2±4.9)%, (70.2±6.8)%, (66.2±5.0)% and (57.4±4.3)% respectively. Significant differences existed with control group (P 0.05). And the overall incidence of postoperative complications had no significant difference between groups A and B (23.7% vs 31.6%, P>0.05). Conclusions Age is a major prognostic factor for osteosarcoma. And extremity-sparing surgery and prosthetic reconstruction are effective treatments for children with osteosarcoma. Key words: Osteosarcoma; Child; Limbs

Commentary on “A Case of Paratesticular Leiomyosarcoma Successfully Treated with Orchiectomy and Chemotherapy”

Esophageal carcinosarcoma is a rare cancer type, which accounts for approximately 3% in esophageal neoplasms with low 5-year overall survival. Carcinosarcoma is biphasic in nature which consists of both carcinomatous and sarcomatous elements. Of these sarcomatous components, fibrosarcoma is the most common type and others include leiomyosarcoma, rhabdomyosarcoma, chondrosarcoma, osteosarcoma, liposarcoma, chondrosarcoma and so on. Since the first description of this neoplasm by Chapman in 1877, esophageal carcinosarcoma cases have been reported, but its pathogenesis is still unclear. Here, we report a case with complete follow-up data and integrated high-throughput data, which could contribute to elucidating the pathophysiological mechanisms of diseases accurately and provide novel therapeutic strategies to the clinical research. To the best of our knowledge, this is the first reported case to characterize its characteristics at multi-omics levels.

10009 Background: Advanced high grade sarcomas resistant to standard chemotherapy are usually rapidly fatal. Few drugs with antisarcoma activity are available. Molecular studies of sarcomas suggest that SRC and downstream focal-adhesion kinase are active in sarcoma and may contribute to malignant phenotype. Dasatinib is an orally-administered kinase inhibitor of SRC-family of kinases that exhibited anti-sarcoma activity in preclinical models. SARC undertook a phase II study of dasatinib in advanced sarcoma. Results of patients (pts) treated for high grade subtypes are presented. Methods: An open-label, single-arm study of dasatinib was conducted for pts with incurable sarcoma including 7 histologic subtypes of high grade sarcoma. A Bayesian hierarchical model was used to “borrow strength” statistically across the subtypes. Dasatinib 100 mg bid was initially administered but was reduced to a starting dose of 70 mg bid because of toxicity. Primary endpoint was objective response within or stable disease at 6 months (CBR) per Choi criteria, and disease was imaged every 2 months. For each subtype, if there was < 1% chance the CBR was > 25%, then accrual within that subtype was stopped. Results: 47 leiomyosarcoma (LMS), 42 undifferentiated pleomorphic sarcoma (UPS), 45 osteosarcoma (OS), 17 Ewing's, 14 malignant peripheral nerve sheath tumor, 13 rhabdomyosarcoma (RMS) and 11 liposarcoma (LPS) pts were evaluable for response. Accrual was discontinued early in Ewing's, RMS and LPS because of lack of activity. 8 pts with UPS, 6 LMS and 5 OS had response or stable disease. The probability that the CBR was >25% in UPS was 0.10 and in the other 6 subtypes was < 0.01. The most common adverse events (AEs) were constitutional, gastrointestinal and respiratory. 24% of pts had ≥ grade 3 AEs at least possibly related to dasatinib, and 29% required dose reduction due to toxicity. Conclusions: Dasatinib may have activity in UPS but appears inactive as a single agent in selected other subtypes of advanced high grade sarcoma. Archived tumor tissue will be used to explore the potential basis for activity in UPS. Dasatinib 70 mg bid is safe, but up to 1/3 pts required dose reduction for AEs. No significant financial relationships to disclose.

Sarcomas represent a heterogeneous set of malignant tumors originating from mesenchymal cells. Liposarcomas (LPS) and Leiomyosarcomas (LMS) are two of the most common histotypes, accounting for approximately 25% and 30% of all soft tissue sarcomas, respectively. The most frequent form of LPS is represented by a spectrum of disease including well-differentiated LPS (WDLPS), a non-metastasizing but locally recurrent disease with adipocytic differentiation, and de-differentiated LPS (DDLPS), an aggressive, frequently metastasizing high grade sarcoma which can arise in conjunction with elements of WDLPS. Besides the known oncogenic KIT or PDGFRA driver mutations in GIST, somatic alterations in RB1, deletions in PTEN, MDM2 amplifications in LPS, and TP53 mutations in LMS are the most commonly reported genomic aberrancies identified in sarcomas. Both WDLPS and DDLPS share amplification of 12q13-15, a genomic region containing the MDM2 and CDK4 loci, yet little is understood about the other genetic processes that yield such different phenotypes. In LMS, recurrent mutations in TP53 have been identified, but a detailed analysis of primary and metastatic tumors has not previously been described. To evaluate genetic events in these transitions, we performed whole exome sequencing (WES) on trios comprising normal tissue, WDLPS, and DDLPS obtained from individual patients (n = 19), as well as on trios of normal tissue, primary and metastatic LMS tumors obtained from separate individual patients (n = 8). Consistent with prior reports of the molecular characterization of LPS, we observed arm-level amplifications in Chr 12 in all LPS samples, and Chr 17 amplification in many LMS cases. There were no shared somatic alterations across paired WDLPS and DLPS pairs from individual patients aside from the common Chr 12 amplification (MDM2 &amp; CDK4). A higher mutation rate was observed in LMS, and there were many clonal somatic alterations shared between the primary and metastatic lesions of individuals. This study demonstrates the heterogeneity of evolution between different subtypes of sarcomas using whole exome sequencing of clinical specimens. This finding has implications for better understanding of the molecular drivers of these tumors and opportunities to identify subtype-specific therapeutic targets. Citation Format: Ali Amin-Mansour, Stefano Sioletic, Scott L. Carter, Levi A. Garraway, George D. Demetri, Suzanne George, Eliezer M. Van Allen, Andrew J. Wagner. Differential evolution of tumor heterogeneity in leiomyosarcomas and liposarcomas suggested by genomic profiling. [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 4819. doi:10.1158/1538-7445.AM2015-4819

Introduction: Soft tissue sarcomas are rare and heterogenous malignancies with a poor prognosis in advanced disease stages. Eribulin is used in metastatic liposarcoma (LPS) patients, who have failed first-line chemotherapy and has been approved for use in patients with LPS in the USA and Europe due to its efficacy in this histological subtype in a phase 3 trial. We have evaluated efficacy and tolerability of eribulin in LPS and leiomyosarcoma (LMS) patients in the routine clinical setting at our department. Methods: In this retrospective single-center analysis, efficacy and safety of eribulin were retrospectively evaluated in advanced LPS and LMS patients at the Division of Oncology, Medical University of Vienna. Results: A total of 32 adult patients treated with eribulin were identified and included in this analysis. Overall response rate was 9.4% for all patients, with one patient with LPS and two patients with LMS showing a partial response. Disease control rate (partial response plus stable disease) for all patients was 50% (LPS: 47.1%; LMS 53.3%). No statistically significant difference in median progression-free survival and overall survival was detected between patients with LPS and LMS (p = 0.807 and p = 0.519, respectively). Patients with LMS (n = 2) had received fewer previous therapy lines than patients with LPS (n = 14) (≤ previous treatment lines, p < 0.001). Toxicity was generally manageable, and grade 3 + 4 events were rare. Conclusion: The activity and tolerability of eribulin in LPS as in well in LMS patients in the routine clinical setting is comparable to outcomes reported in published phase 3 trials.

Ultrastructural studies in the preoperative cytologic diagnosis of soft tissue tumors.

Histology-driven tailoring of surgical approaches for retroperitoneal soft tissue sarcoma is currently under debate. Compelling evidence assessing the role of histology-dependent extent of resection is lacking. The aim of this study was to assess outcomes of patients with primary retroperitoneal liposarcoma (LPS) or leiomyosarcoma (LMS) according to whether comprehensive (formerly 'compartmental') resection (CR) was performed. A retrospective study was conducted on data from patients undergoing surgical resection for LPS and LMS at Heidelberg University Hospital (2002-2019). Parameters were compared between groups with and without CR, with subgroup analyses for grading (LPS). Kaplan-Meier and Cox regression analyses were used to identify predictors of disease-specific survival (DSS), local recurrence-free survival, and distant metastasis-free survival. In total, 119 patients with primary LPS and 46 patients with primary LMS were identified. DSS was improved in patients with LPS with CR (P = 0.049), and both DSS (P = 0.040) and distant metastasis-free survival (P = 0.041) were improved in the subgroup of patients with primary G3 LPS. In contrast, CR in patients with LMS was not associated with improved DSS, local recurrence-free survival, or distant metastasis-free survival. CR was associated with more severe postoperative complications (P = 0.021) and a longer hospital stay (P = 0.013) in patients with LPS, longer operation times (P < 0.010) in both patients with LPS and LMS, and increased blood loss (P = 0.008) in patients with LMS. CR is associated with improved DSS in patients with primary LPS, which is not the case in patients with primary LMS. Given the association between CR and increased perioperative morbidity, surgical strategies for retroperitoneal soft tissue sarcoma should be individualized according to the underlying histology.