Malignant Fibrous Histiocytoma Research Articles

Undifferentiated high-grade pleomorphic sarcoma of the common bile duct: A case report and review of literature

BACKGROUND Undifferentiated pleomorphic sarcoma (UPS) is a rare malignant mesenchymal tumor with a poor prognosis. It mainly occurs in the extremities, trunk, head and neck, and retroperitoneum regions. Owing to the lack of specific clinical manifestations and imaging features, UPS diagnosis mainly depends on pathological and immunohistochemical examinations for exclusive diagnosis. Here we report an extremely rare case of high-grade UPS in the common bile duct (CBD). There are limited available data on such cases. CASE SUMMARY A 70-year-old woman was admitted to our department with yellow eyes and urine accompanied by upper abdominal distending pain for 2 wk. Her laboratory data suggested significantly elevated hepatorenal function levels. The imaging data revealed calculous cholecystitis, intrahepatic and extrahepatic bile duct dilation with extrahepatic bile duct calculi, and a space-occupying lesion at the distal CBD. After endoscopic biliary stenting and symptomatic support therapy, CBD exploration and biopsy were performed. The frozen section indicated malignant spindle cell tumor of the CBD mass, and further radical pancreaticoduodenectomy was performed. Finally, the neoplasm was diagnosed as a high-grade UPS combined with the light-microscopic morphology and immunohistochemical results. CONCLUSION This extremely rare case highlighted the need for increasing physicians' vigilance, reducing the odds of misdiagnosis, and providing appropriate treatment strategies.

Pancreatic metastasis from undifferentiated pleomorphic sarcoma. An extremely rare entity

Pancreatic metastasis from undifferentiated pleomorphic sarcoma. An extremely rare entity

Sarcomatoid and Rhabdoid Renal Cell Carcinoma: Clinical, Pathologic, and Molecular Genetic Features.

Renal cell carcinoma (RCC) with sarcomatoid and rhabdoid morphologies has an aggressive biological behavior and a typically poor prognosis. The current 2022 WHO classification of renal tumors does not include them as distinct histologic entities but rather as transformational changes that may arise in a background of various distinct histologic types of RCC. The sarcomatoid component shows malignant spindle cells that may grow as intersecting fascicles, which is reminiscent of pleomorphic undifferentiated sarcoma. The rhabdoid cells are epithelioid cells with eccentrically located vesicular nuclei with prominent nucleoli and large intracytoplasmic eosinophilic inclusions. Studies have shown that RCCs with sarcomatoid and rhabdoid differentiation have distinctive molecular features. Sarcomatoid RCC harbors shared genomic alterations in carcinomatous and rhabdoid components, but also enrichment of specific genomic alterations in the sarcomatoid element, suggesting molecular pathways for development of sarcomatoid growth from a common clonal ancestor. Rhabdoid differentiation also arises through clonal evolution although less is known of specific genomic alterations in rhabdoid cells. Historically, treatment has lacked efficacy, although recently immunotherapy with PD-1/PD-L1/CTLA-4 inhibitors has produced significant clinical responses. Reporting of sarcomatoid and rhabdoid features in renal cell carcinoma is required by the College of American Pathologists and the International Collaboration on Cancer Reporting. This manuscript reviews the clinical, pathologic, and molecular features of sarcomatoid RCC and rhabdoid RCC with emphasis on the morphologic features of these tumors, significance of diagnostic recognition, the molecular mechanisms of tumorigenesis and differentiation along sarcomatoid and rhabdoid lines, and advances in treatment, particularly immunotherapy.

Osteosarcoma Arising as a Secondary Malignancy following Treatment for Hematologic Cancer: A Report of 33 Affected Patients from the Cooperative Osteosarcoma Study Group (COSS)

Purpose: Osteosarcoma may arise as a secondary cancer following leukemias or lymphomas. We intended to increase the knowledge about such rare events. Patients and methods: We searched the Cooperative Osteosarcoma Study Group’s database for individuals who developed their osteosarcoma following a previous hematological malignancy. The presentation and treatment of both malignancies was investigated, and additional neoplasms were noted. Outcomes after osteosarcoma were analyzed and potential prognostic factors were searched for. Results: A total of 33 eligible patients were identified (male: 23, female: 10; median age: 12.9 years at diagnosis of hematological cancer; 20 lymphomas, 13 leukemias). A cancer predisposition syndrome was evident in one patient only. The hematological cancers had been treated by radiotherapy in 28 (1 unknown) and chemotherapy in 26 cases, including bone-marrow transplantation in 9. The secondary bone sarcomas (high-grade central 27, periosteal 2, extra-osseous 2, undifferentiated pleomorphic sarcoma of bone 2) arose after a median lag-time of 9.4 years, when patients were a median of 19.1 years old. Tumors were considered radiation-related in 26 cases (1 unknown). Osteosarcoma-sites were in the extremities (19), trunk (12), or head and neck (2). Metastases at diagnosis affected eight patients. Information on osteosarcoma therapy was available for 31 cases. All of these received chemotherapy. Local therapy involved surgery in 27 patients, with a good response reported for 9/18 eligible patients. Local radiotherapy was given to three patients. The median follow-up was 3.9 (0.3–12.0) years after bone tumor diagnosis. During this period, 21 patients had developed events as defined, and 15 had died, resulting in 5-year event-free and overall survival rates of 40% (standard error: 9%) and 56% (10%), respectively. There were multiple instances of additional neoplasms. Several factors were found to be of prognostic value (p < 0.05) for event-free (osteosarcoma site in the extremities) or overall (achievement of a surgical osteosarcoma-remission, receiving chemotherapy for the hematologic malignancy) survival. Conclusions: We were able to prove radiation therapy for hematological malignancies to be the predominant risk factor for later osteosarcomas. A resulting overrepresentation of axial and a tendency towards additional neoplasms affects prognosis. Still, selected patients may become long-term survivors with appropriate therapies, which is an argument against therapeutic negligence.

68Ga-Fibroblast Activation Protein Inhibitor PET/CT Improves Detection of Intermediate and Low-Grade Sarcomas and Identifies Candidates for Radiopharmaceutical Therapy.

Fibroblast activation protein-α (FAP) is often highly expressed by sarcoma cells and by sarcoma-associated fibroblasts in the tumor microenvironment. This makes it a promising target for imaging and therapy. The level of FAP expression and the diagnostic value of 68Ga-FAP inhibitor (FAPI) PET for sarcoma subtypes are unknown. We assessed the diagnostic performance and accuracy of 68Ga-FAPI PET in various bone and soft-tissue sarcomas. Potential eligibility for FAP-targeted radiopharmaceutical therapy (FAP-RPT) was evaluated. Methods: This prospective observational trial enrolled 200 patients with bone and soft-tissue sarcoma who underwent 68Ga-FAPI PET/CT and 18F-FDG PET/CT (186/200, or 93%) for staging or restaging. The number of lesions detected and the uptake (SUVmax) of the primary tumor, lymph nodes, and visceral and bone metastases were analyzed. The Wilcoxon test was used for semiquantitative assessment. The association of 68Ga-FAPI uptake intensity, histopathologic grade, and FAP expression in sarcoma biopsy samples was analyzed using Spearman r correlation. The impact of 68Ga-FAPI PET on clinical management was investigated using questionnaires before and after PET/CT. Eligibility for FAP-RPT was defined by an SUVmax greater than 10 for all tumor regions. Results: 68Ga-FAPI uptake was heterogeneous among sarcoma subtypes. The 3 sarcoma entities with the highest uptake (mean SUVmax ± SD) were solitary fibrous tumor (24.7 ± 11.9), undifferentiated pleomorphic sarcoma (18.8 ± 13.1), and leiomyosarcoma (15.2 ± 10.2). Uptake of 68Ga-FAPI versus 18F-FDG was significantly higher in low-grade sarcomas (10.4 ± 8.5 vs. 7.0 ± 4.5, P = 0.01) and in potentially malignant intermediate or unpredictable sarcomas without a World Health Organization grade (not applicable [NA]; 22.3 ± 12.5 vs. 8.5 ± 10.0, P = 0.0004), including solitary fibrous tumor. The accuracy, as well as the detection rates, of 68Ga-FAPI was higher than that of 18F-FDG in low-grade sarcomas (accuracy, 92.2 vs. 80.0) and NA sarcomas (accuracy, 96.9 vs. 81.9). 68Ga-FAPI uptake and the histopathologic FAP expression score (n = 89) were moderately correlated (Spearman r = 0.43, P < 0.0002). Of 138 patients, 62 (45%) with metastatic sarcoma were eligible for FAP-RPT. Conclusion: In patients with low-grade and NA sarcomas, 68Ga-FAPI PET demonstrates uptake, detection rates, and accuracy superior to those of 18F-FDG PET. 68Ga-FAPI PET criteria identified eligibility for FAP-RPT in about half of sarcoma patients.

Undifferentiated Pleomorphic Sarcoma of the Face

Undifferentiated Pleomorphic Sarcoma of the Face

Factors Influencing Long-Term Local Recurrence, Distant Metastasis, and Survival in Patients with Soft Tissue Sarcoma of the Extremities Treated with Radiotherapy

Introduction: The prognostic factors for extremity soft-tissue sarcomas (ESTSs) treated with multimodal surgery and radiotherapy (RT) remain a subject of debate across diverse and heterogeneous studies. Methods: We retrospectively analyzed nonmetastatic ESTS patients treated with RT between 2007 and 2020 in Strasbourg, France. We assessed local control (LC), distant control (DC), overall survival (OS), and complications. Results: A total of 169 patients diagnosed with localized ESTS were included. The median age was 64 years (range 21–94 years). ESTS primarily occurred proximally (74.6%) and in the lower limbs (71%). Most tumors were grade 2–3 (71.1%), deep-seated (86.4%), and had R0 margins (63.9%). Most patients were treated with helical tomotherapy (79.3%). The median biologically effective dose (BED) prescribed was 75 BEDGy4 (range 45.0–109.9). The median follow-up was 5.5 years. The 5- and 10-year LC, DC, and OS rates were 91.7%, 76.8%, and 83.8% and 84.2%, 74.1%, and 77.6%, respectively. According to the univariate analysis, LC was worse for patients who received less than 75 BEDGy4 (p = 0.015). Deep tumors were associated with worse OS (p &lt; 0.05), and grade 2–3 and undifferentiated pleomorphic sarcoma (UPS) were linked to both shorter DC and shorter OS (p &lt; 0.05). IMRT was associated with longer LC than 3DRT (p = 0.018). Multivariate analysis revealed that patients with liposarcoma had better OS (p &lt; 0.05) and that patients with distant relapse had shorter OS (p &lt; 0.0001). Conclusion: RT associated with surgical resection was well tolerated and was associated with excellent long-term rates of LC, DC, and OS. Compared with 3DRT, IMRT improved local control. Liposarcoma was a favorable prognostic factor for OS. Intermediate- and high-grade tumors and deep tumors were associated with lower DC and OS.

High-Grade Pleomorphic Sarcomas Treated with Immune Checkpoint Blockade: The MD Anderson Cancer Center Experience.

Undifferentiated pleomorphic sarcomas (UPSs) are amongst the most common subtypes of soft-tissue sarcomas. Few real-world data on the use of immune checkpoint blockade (ICB) in UPS patients and other high-grade pleomorphic STS patients are available. The purpose of our study is to describe the efficacy and toxicity of ICB in patients with advanced UPSs and other high-grade pleomorphic sarcomas treated at our institution. This is a retrospective, observational study of all patients with metastatic high-grade pleomorphic sarcomas treated with FDA-approved ICB at MD Anderson Cancer Center between 1 January 2015 and 1 January 2023. Patients included in trials for which results are not yet published were excluded. Thirty-six patients with advanced/metastatic pleomorphic sarcomas were included. The median age was 52 years. A total of 26 patients (72%) had UPSs and 10 patients (28%) had other high-grade pleomorphic sarcomas. The median follow-up time was 8.8 months. The median PFS was 2.9 months. The 3-month PFS and 6-month PFS were 46% and 32%, respectively. The median OS was 12.9 months. The 12-month OS and 24-month OS were 53% and 29%, respectively. The best response, previous RT, and type of ICB treatment were significantly and independently associated with shorter PFS (p = 0.0012, p = 0.0019 and p = 0.036, respectively). No new safety signal was identified, and the toxicity was overall manageable with no toxic deaths and only four patients (11%) stopping treatment due to toxicity. Real-world retrospective data are consistent with the published literature, with a promising 6-month PFS of 32%. Partial or stable responders to ICB treatment have significantly improved PFS compared to progressors.

Genomic profiling of pleomorphic rhabdomyosarcoma reveals a genomic signature distinct from that of embryonal rhabdomyosarcoma.

Pleomorphic rhabdomyosarcoma (PRMS) is a rare and highly aggressive sarcoma, occurring mostly in the deep soft tissues of middle-aged adults and showing a variable degree of skeletal muscle differentiation. The diagnosis is challenging as pathologic features overlap with embryonal rhabdomyosarcoma (ERMS), malignant Triton tumor, and other pleomorphic sarcomas. As recurrent genetic alterations underlying PRMS have not been described to date, ancillary molecular diagnostic testing is not useful in subclassification. Herein, we perform genomic profiling of a well-characterized cohort of 14 PRMS, compared to a control group of 23 ERMS and other pleomorphic sarcomas (undifferentiated pleomorphic sarcoma and pleomorphic liposarcoma) using clinically validated DNA-targeted Next generation sequencing (NGS) panels (MSK-IMPACT). The PRMS cohort included eight males and six females, with a median age of 53 years (range 31-76 years). Despite similar tumor mutation burdens, the genomic landscape of PRMS, with a high frequency of TP53 (79%) and RB1 (43%) alterations, stood in stark contrast to ERMS, with 4% and 0%, respectively. CDKN2A deletions were more common in PRMS (43%), compared to ERMS (13%). In contrast, ERMS harbored somatic driver mutations in the RAS pathway and loss of function mutations in BCOR, which were absent in PRMS. Copy number variations in PRMS showed multiple chromosomal arm-level changes, most commonly gains of chr17p and chr22q and loss of chr6q. Notably, gain of chr8, commonly seen in ERMS (61%) was conspicuously absent in PRMS. The genomic profiles of other pleomorphic sarcomas were overall analogous to PRMS, showing shared alterations in TP53, RB1, and CDKN2A. Overall survival and progression-free survival of PRMS were significantly worse (p < 0.0005) than that of ERMS. Our findings revealed that the molecular landscape of PRMS aligns with other adult pleomorphic sarcomas and is distinct from that of ERMS. Thus, NGS assays may be applied in select challenging cases toward a refined classification. Finally, our data corroborate the inclusion of PRMS in the therapeutic bracket of pleomorphic sarcomas, given that their clinical outcomes are comparable.

A Rare Case of Undifferentiated Pleomorphic Cardiac Sarcoma

A Rare Case of Undifferentiated Pleomorphic Cardiac Sarcoma

P133 Anti-synthetase syndrome: an experience from a tertiary referral center

Abstract Background/Aims Anti-synthetase syndrome (ASS) is a subset of Idiopathic inflammatory myositis (IIMs). It is a syndromic diagnosis classified by Connors et al. and Solomon et al. criteria. Raynaud’s phenomenon (RP), fever, arthritis, mechanics hands, ILD and myositis constitute this syndrome along with the classical Anti-aminoacyl tRNA synthetase antibodies (ARS). About 25% of IIMs patients are classified as ASS. This study was planned to evaluate the prevalence of ASS; their phenotype, antibody subtypes, treatment responsiveness and outcomes. Methods All consecutive ASS patients were enrolled in the study fulfilling Connors et al. criteria during January, 2016 to August2023. Their demographic details, clinical features, laboratory and imaging features, treatment were analyzed. ARS were considered positive on a Line Immunoassay with cutoff &amp;gt;6U/ML using BlueDriverQuantrix-ANA25 Screen IgG kit (includes Jo1, Pl-7, Pl-12) from D-tek, Belgium including three ASS antibodies (Jo-1, PL-12, PL-7). Anti EJ, OJ antibodies were not present in the kit. Descriptive analysis were used to describe disease characteristics. Results Among 139 total IIM patients, 21(15%) patients were diagnosed with ASS. All patients fulfilled Connors et al. criteria while 66.6% patients fulfilled stricter criteria by Solomon et al. Mean(±SD) age group was 43(±16.4) years. 71.4% were Females. Anti Jo-1 was the predominant antibody seen in 66.6% while Anti PL-12 and Anti Pl-7 antibodies were present in 19% and 14.3% respectively. 66.6% had ANA positivity and MAA antibodies were seen in 52.3%. Rash was seen in 61.9%, mechanics hands in 38%, RP in 52.3% fever in 38% ,arthritis in 57%, myositis 62% and ILD in 80.9%. NSIP (66.6%) was the predominant type, followed by OP (9.5%) and UIP (4.7%). Median (IQR) CPK level was 736 (210-4556)U/L. Anti Jo-1 patients had higher prevalence of mechanics hands and rash whereas ILD was observed in all cases of Anti PL-7 and Anti PL-12 antibodies. Malignancy was seen in two patients (Malignant fibrous histiocytoma, Metastatic Pancreatic carcinoma). Mean (SD) MMT8 score was 62.8(±22.2) at presentation . Treatment is with steroids in all cases followed by maintenance with azathioprine in 57.1%, Methotrexate in 14.2%. Rituximab was used in 14.2%, cyclophosphamide in 9.5% and mycophenolate mofetil in 23.8%. Mortality was seen in one patient with respiratory failure. Lung involvement was severe in patients with both MSA and MAA positivity. 62% patients were in remission. Conclusion ILD and Arthritis were the main presenting complaints in our cohort. Myositis is relatively less prevalent in ASS. NSIP was the predominant ILD subtype. Non Jo-1 group had high MAA positivity. Jo-1 was associated with mechanic’s hands and rash. Malignancy was less prevalent in ASS. All patients with PL-7 and PL-12 antibodies had lung involvement. Biologics were required in few refractory cases. Disclosure P. Khatri: None. J.R. Yadavalli: None. S. Dhuria: None. N. Negalur: None. K. Shivam: None. R. Gupta: None.

Oncogene-induced matrix reorganization controls CD8+ T cell function in the soft-tissue sarcoma microenvironment.

CD8+ T cell dysfunction impedes anti-tumor immunity in solid cancers but the underlying mechanisms are diverse and poorly understood. Extracellular matrix (ECM) composition has been linked to impaired T cell migration and enhanced tumor progression; however, impacts of individual ECM molecules on T cell function in the tumor microenvironment (TME) are only beginning to be elucidated. Upstream regulators of aberrant ECM deposition and organization in solid tumors are equally ill-defined. Therefore, we investigated how ECM composition modulates CD8+ T cell function in undifferentiated pleomorphic sarcoma (UPS), an immunologically active desmoplastic tumor. Using an autochthonous murine model of UPS and data from multiple human patient cohorts, we discovered a multifaceted mechanism wherein the transcriptional co-activator YAP1 promotes collagen VI (COLVI) deposition in the UPS TME. In turn, COLVI induces CD8+ T cell dysfunction and immune evasion by remodeling fibrillar collagen and inhibiting T cell autophagic flux. Unexpectedly, collagen I (COLI) opposed COLVI in this setting, promoting CD8+ T cell function and acting as a tumor suppressor. Thus, CD8+ T cell responses in sarcoma depend upon oncogene-mediated ECM composition and remodeling.

The use of vascularized fibula flap with allograft in post-oncologic microsurgical bone reconstruction of lower limbs in pediatric patients.

Post-oncologic surgical reconstruction of lower limbs in pediatrics remains a challenging topic. Microsurgical techniques allow reconstructions of large bony defects. The use of vascularized fibular flap with allograft has proven to be an ideal biologic construct. We aim to assess the success rate of this operation, including flap survival, bony union, weight-bearing ambulation, and complications in a long-term follow-up in our case series compared to the literature. Our case-series includes 18 femoral resections (9 osteosarcomas, 8 Ewing sarcoma, and 1 desmoid tumor) and 15 tibial resections (10 osteosarcoma, 4 Ewing sarcoma, and 1 Malignant Fibrous Histiocytoma). We collected patients' demographics, type of tumor, type of resection, defect size, fibula-flap length, method of fixation, anastomosis site, follow-up data, complications, and their management. All survivals were examined by X-ray and CT-scan to evaluate the morphological changes of the vascularized fibula and follow-up. The functional evaluation was performed by the 30-point Musculoskeletal Tumor Society Rating Score (MSTS) for the lower limb (Enneking et al., Clinical Orthopaedics and Related Research 1993(286):241-246). The mean age of the femur resection patients' group was 11.2 years with a mean defect size of 14 cm and a mean length of the fibular flap of 18 cm; for the tibia the mean age was 12 years with a mean defect size of 14 cm and a mean length of the fibular flap of 16.6 cm. The overall survival of the reconstructions at 5 years follow-up was 17 out 18 cases for the femur and 13 out of 15 cases for the tibia. MSTS score was 28.2 for the femur and 23.7 for the tibia. The average time of union of the fibula was seen after 5 months, while allograft consolidation was observed around 19.7 months. The mean time of follow-up was 144.5 months for the femur and 139.2 months for the tibia. The complication rate observed was 7 out of 18 for the femur and 7 out of 15 for the tibia reconstructions. The viability of the fibula is a cornerstone in the success of reconstruction as well as the successful management of complications in intercalary defects after tumor resection in pediatrics to restore good functionality. Our results are in line with those reported in the literature in terms of overall complication rates. The high primary union of allograft, the high MSTS score obtained, and the low rate of severe complications reflect the mechanical role of this reconstructive technique over a long follow-up.

Undifferentiated Pleomorphic Sarcoma of the Distal Thigh: A Case Report

Undifferentiated Pleomorphic Sarcoma of the Distal Thigh: A Case Report

Abstract CT188: A Phase I trial of AVA6000, a Fibroblast Activation Protein (FAP)-released and tumor microenvironment (TME)-targeted doxorubicin peptide drug conjugate in patients with FAP-positive solid tumors

Abstract Background: AVA6000 is a peptide drug conjugate, consisting of a peptide moiety that is specifically cleaved by FAP in the TME that is bound to doxorubicin. FAP is selectively overexpressed in many solid tumors. The peptide moiety linker (pre|CISIONTM) prevents cellular entry of doxorubicin unless cleaved by FAP, thus enabling targeted delivery of doxorubicin to tumors. Design: The safety, PK and preliminary efficacy of AVA6000 was studied in a first-in-man, multicenter dose escalation phase I trial. AVA6000 was administered intravenously q3w using a standard 3+3 design in patients with locally advanced or metastatic solid tumors reported to be FAP-positive. PK (AUC) based dosing was implemented to calculate maximum cycles of AVA6000 with the cumulative limit of 550 mg/m2. Results: Forty patients (median age 65 years, range 30-79), with median 3 prior lines of therapy (range, 0-7) received escalating AVA6000 doses from 80mg/m2 (51 mg/m2 doxorubicin; molar equivalent, 0.675) to 385 mg/m2 (260 mg/m2 doxorubicin equivalent). Tumor types included soft tissue sarcoma (30%), colorectal cancer (27.5%), pancreatic cancer (20%), cancers of the biliary tract (7.5%). The safety profile was favorable, the most frequent adverse events (any grade) being fatigue (50%), alopecia (42.5%), and nausea (32.5%), with rare grade 3-4 hematologic toxicities of neutropenia (7.5%), anemia, thrombocytopenia, and WBC decreased (5% each). Grade 3 non-hematologic toxicities included mucositis, fatigue and hematemesis (n=1 each). No grade 4 non-hematologic toxicities were reported. Two DLTs were observed of grade 2 cardiac failure (120 mg/m2; LVEF decrease 61 to 39%) and grade 4 neutropenia/thrombocytopenia (200 mg/m2). AVA6000 distributes rapidly with a t1/2 of 45 min. The Cmax of released doxorubicin was reduced as compared to standard dose doxorubicin (range 78-93% reduction) across dose cohorts. Tumor biopsy data demonstrate concentration of doxorubicin in the TME of mean 860 ng/gm (range 76-2310 ng/gm, n=9). In contrast, blood samples taken with the biopsy demonstrate a circulating free doxorubicin of 8.3 ng/ml (range 2.4-15.9), indicating concentration of doxorubicin in the tumor relative to plasma. Using RECISTv.1.1, one PR (-65%) with duration of 6 months was observed in a patient with undifferentiated pleomorphic sarcoma at 160 mg/m2, and a mixed response in a patient with angiosarcoma (SLD -22%) at 200 mg/m2. The disease control rate was 50%, at 12 wks. In each case, SD &amp;gt; 4 months or PR was associated with high FAP enzyme activity in the on-study tumor biopsy compared to observed disease progression as best response (n=6). Conclusions: AVA6000 delivers high concentration of doxorubicin to the TME relative to plasma which results in antitumor activity in tumors with high FAP activity. A q2w dose escalation arm is ongoing. Citation Format: Udai Banerji, Natalie Cook, Alan Anthoney, Ruth Plummer, William D. Tap, Jeffry T. Evans, Lee D. Cranmer, Christopher Plummer, Paul Loadman, Gezim Lahu, Huw S. Jones, Nelson Kinnersley, Fiona McLaughlin, Chris Twelves. A Phase I trial of AVA6000, a Fibroblast Activation Protein (FAP)-released and tumor microenvironment (TME)-targeted doxorubicin peptide drug conjugate in patients with FAP-positive solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT188.

Natural history of undifferentiated pleomorphic sarcoma: Experience from the US Sarcoma Collaborative.

Undifferentiated pleomorphic sarcoma (UPS) is a relatively rare but aggressive neoplasm. We sought to utilize a multi-institutional US cohort of sarcoma patients to examine predictors of survival and recurrence patterns after resection of UPS. From 2000 to 2016, patients with primary UPS undergoing curative-intent surgical resection at sevenacademic institutions were retrospectively reviewed. Epidemiologic and clinicopathologic factors were reviewed by site of origin. Overall survival (OS), recurrence-free survival (RFS), time-to-locoregional (TTLR),time-to-distant recurrence (TTDR), and patterns of recurrence were analyzed. Of the 534 UPS patients identified, 53% were female, with a median age of 60 and median tumor size of 8.5 cm. The median OS, RFS, TTLR, and TTDR for the entire cohort were 109, 49, 86, and 46 months, respectively. There were no differences in these survival outcomes between extremity and truncal UPS. Compared with truncal, extremity UPS were more commonly amenable to R0 resection (87% vs. 75%, p = 0.017) and less commonly associated with lymph node metastasis (1% vs. 6%, p = 0.031). R0 resection and radiation treatment, but not site of origin (extremity vs. trunk) were independent predictors of OS and RFS. TTLRrecurrence was shorter for UPS resected with a positive margin and for tumors not treated with radiation. For patients with resected extremity and truncal UPS, tumor size >5 cm and positive resection margin are associated with worse survival OS and RFS, irrespectively the site of origin. R0 surgical resection and radiation treatment may help improve these survival outcomes.

A Retrospective Study of 291 Patients With Head and Neck Sarcomas: Treatment, Outcomes, and Prognostic Factors

AimsSarcomas constitute a group of rare malignant neoplasms, commonly subcategorized into soft tissue sarcomas (STS) and bone sarcomas. This study aims to describe the treatment modalities and outcome of head and neck sarcoma (HNS) patients in western Denmark and to identify prognostic factors for overall survival and recurrence in HNS patients. Materials and methodsThe Aarhus sarcoma registry, The National Danish Sarcoma Database, and the Danish National Pathology Registry were used to identify HNS adult patients diagnosed between 1979 and 2022. ResultsAltogether, 291 patients were included in this study. The prevalent histological subtypes were undifferentiated pleomorphic sarcoma (16%; 48/291) and leiomyosarcoma (15%; 44/291) for STS patients (n = 230) and chondrosarcoma (10%; 28/291) and osteosarcoma (7%; 19/291) for bone sarcoma patients (n = 61). Surgery with curative intent was performed in 71% (164/230) and 70% (43/61) of STS and bone sarcoma patients, respectively. Clear resection was achieved in 59% (97/164) of STS patients and 44% (19/43) of bone sarcoma patients. Eighty-nine patients relapsed (STS n = 66, bone sarcoma n = 23) after a median time of 2.7/5.5 years for STS/bone sarcoma patients. The five-year overall survival rates were 45% for STS patients and 66% for bone sarcoma patients.The following factors were significantly, negatively associated with overall survival in STS patients: Age (hazard ratio (HR)) = 1.02, p < 0.001), tumour size ≥5 cm (HR = 1.75, p = 0.003), metastatic disease (HR = 3.17, p < 0.001), high grade tumour (HR = 2.24, p = 0.004), previous cancer (HR = 2.84, p < 0.001), and high Aarhus composite biomarker score (ACBS) (HR = 4.56, p = 0.001). For relapse in STS patients, higher tumour grade (HR = 3.19, p = 0.014), intralesional margins (HR = 2.84, p < 0.001), ≥2 previous cancers (HR = 3.00, p = 0.004), and high ACBS (HR = 3.29, p = 0.047), were negatively associated. For bone sarcomas only higher age (HR = 1.02, p = 0.049) and intralesional margins (HR = 2.91, p = 0.042) were significant negative factors for overall survival. ConclusionMultiple prognostic factors for overall survival and relapse were identified, especially for STS patients.

Best Overall Response-associated Signature to Doxorubicin in Soft Tissue Sarcomas: A Transcriptomic Analysis from ANNOUNCE.

This exploratory analysis evaluated the tumor samples of the patients treated with doxorubicin (with or without olaratumab) in a negative phase-3 ANNOUNCE trial to better understand the complexity of advanced soft tissue sarcomas (STS) and to potentially identify its predictive markers. RNA sequencing was performed on pretreatment tumor samples (n=273) from the ANNOUNCE trial to evaluate response patterns and identify potential predictive treatment markers for doxorubicin. A BOR-associated signature to doxorubicin (REDSARC) was created by evaluating tumors with radiographic response versus progression. An external cohort of doxorubicin-treated patients from the Spanish Group for Research on Sarcomas (GEIS) was utilized for refinement and validation. A total of 259 samples from the trial were considered for analysis. Comparative analyses by the treatment arm did not explain the negative trial. However, there was an association between the BOR signature and histologic subtype (χ2 P=2.0e-7) and grade (P=0.002). There were no associations between the BOR signature and gender, age, ethnicity or stage. Applied to survival outcomes, REDSARC was also predictive for progression-free (PFS) and overall survival (OS). Using the GEIS cohort, a refined 25-gene signature was identified and applied to the ANNOUNCE cohort, where it was predictive of PFS and OS in leiomyosarcoma, liposarcoma, and other sarcoma subtypes, but not in undifferentiated pleomorphic sarcoma. The refined REDSARC signature provides a potential tool to direct the application of doxorubicin in sarcomas and other malignancies. Validation and further refinement of the signature in other potentially subtype specific prospective cohorts is recommended.

Abstract 3858: Peripheral CD38+ effector memory (EM) T cells are dynamic biomarkers of response to neoadjuvant immune checkpoint blockade (NeoICB) in patients (pts) with resectable dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS)

Abstract Introduction: NeoICB is a promising approach for pts with DDLPS and UPS. However, biomarkers to identify which pts benefit from this treatment and understanding the mechanisms of response and resistance to ICB remains a challenge. Methods: We conducted a randomized phase 2 trial of neoICB (anti-PD1 +/- CTLA4) in pts with resectable DDLPS (n=17) and UPS (n=10). Pts with UPS received concurrent neoICB and radiation. The primary endpoint of the trial was pathological response; 3 DDLPS and 9 UPS pts were responders (R) and 14 DDLPS and 1 UPS pts were non-responders (NR). Peripheral blood mononuclear cells (PBMCs) were collected at baseline, prior to cycle 2 of neoICB (C2D1), and at the time of surgery (SURG). We performed mass cytometry (CyTOF) to identify immune cells associated with response and their dynamic changes with neoICB. We designed a custom 41-parameter panel using CD45 live cell barcoding with 31 markers for immune profiling, of which 23 were selected to detect key cell lineage and 8 to detect signaling markers. Batch correction and high dimensional data analyses were performed using CyCombine and CyTOF workflow R packages. Longitudinal comparisons between immune cell populations were conducted using Mann-Whitney U Test. Results: Of 79 available PBMC samples from 27 pts, 63 passed quality control after thawing (≥30% viability) and data clean-up (at least 10,000 events). Data was down-sampled to 5000 events for analysis. Of 19 immune cell types identified, monocytes were the most common followed by CD4+ and CD8+ T cells. There was an early increase in CD38+ effector/effector memory (EM) T cells at C2D1 in pts with DDLPS (CD8+ p=0.005, CD4+ p&amp;lt;0.001) and a similar increase observed in pts with UPS (CD8+ C2D1 p=NS, SURG p=0.034; CD4+ C2D1 p=0.024, SURG p=0.06) and these cells had higher Ki67 expression than CD38- T cells (p&amp;lt;0.005). At baseline, R pts with DDLPS had higher fractions of CD38+ EM CD8+ T cells than NR pts (p=0.044). Analysis in the UPS cohort was limited by the low number of NR pts. Higher expression of TIGIT was observed on CD38+ EM CD8+ T cells compared to CD38- counterparts at all time points. Conclusion: Peripheral CD38+ EM CD8+ T cells are associated with response to neoICB in pts with DDLPS. Longitudinal peripheral immune profiling reveals an increase in CD38+ EM CD8+ and CD4+ T cells with neoICB in pts with DDLPS and UPS. These cells are proliferative and express higher levels of TIGIT, which could be a future target for therapeutic exploration. Importantly, changes in the peripheral immune populations may precede changes in the tumor microenvironment (TME) as preliminary analyses of the TME did not identify early (C2D1) changes. TME imaging mass cytometry analyses are currently underway to associate peripheral and intratumor changes in immune populations. Citation Format: Elise F. Nassif, Hsinyi Lu, Michael Stanford, Karen Millerchip, Diana Romero, Jared Malke, Brenna Matejka, Jeffrey E. Gershenwald, Susmita Kumari, Duncan H. Mak, Angelique J. Lin, Jared K. Burks, Wei-Lien Wang, Alexander J. Lazar, Neeta Somaiah, Cara Haymaker, Christina L. Roland, Emily Z. Keung. Peripheral CD38+ effector memory (EM) T cells are dynamic biomarkers of response to neoadjuvant immune checkpoint blockade (NeoICB) in patients (pts) with resectable dedifferentiated liposarcoma (DDLPS) and undifferentiated pleomorphic sarcoma (UPS) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3858.

Abstract 4340: Profiling the evolutionary history of giant cancer cells in sarcomas: Hopeful monsters or an evolutionary dead end

Abstract Background: As tumors evolve, they accumulate somatic mutations that serve as an archeological record of their evolutionary past. Undifferentiated pleomorphic sarcomas (USARCs) are malignant soft tissue tumors that often contain scattered giant cancer cells, or potential ‘hopeful monster cells’, histologically. As USARCs frequently undergo whole genome doubling (WGD) and chromothripsis (Steele et al, 2019), both mutational events are likely to contribute to the formation of giant cancer cells, which frequently display atypical nuclear features such as polyploidy, micronuclei and extrachromosomal DNA. Giant cancer cells are also a common histological finding in other sarcoma types, such as dedifferentiated liposarcomas. Aims: This study aims to leverage single cell sequencing approaches to determine the evolutionary history and genomic landscape of giant cancer cells in sarcomas. Methods: 112 giant cancer cells identified in 8 USARCs, 1 dedifferentiated liposarcoma (DDLPS) and 1 myxofibrosarcoma by histology (i.e. nuclear size and shape, as well as multi-nucleation) were isolated via laser capture microdissection thereby retaining important spatial and morphological information. Once isolated, single cell DNA was extracted and amplified using the Ampli1 whole genome amplification (WGA) kit and underwent WGS. DNA was also estimated at a single cell level in one USARC using FACS. Once sorted into different ploidy populations, single nuclei also underwent WGS. Allele specific copy number aberrations (CNAs) were inferred in all single cells. Bulk tumour and normal WGS was also performed. Results: LCM isolated giant cancer cells exhibited extreme sub-clonal heterogeneity with some demonstrating de novo chromothripsis events that was not present in bulk WGS. FACS analysis and copy number inference of single cancer cells in one USARC also revealed the presence of three ploidy populations, including a haploid, a near diploid and a WGD population. Single cell WGS and copy number profiling demonstrated that following near genome scale haploidisation, multiple haploid cells underwent successive rounds of WGD. Conclusions: Chromothripsis and WGD emerges as major contributors to intra-tumor heterogeneity in sarcoma giant cancer cells. Single cell LCM and WGS revealed that some giant cancer cells contained de novo chromothripsis events that were not observed in bulk WGS. Multiple sub-clonal WGD events also permitted one USARC to continue to explore its fitness landscape contributing to ongoing tumor heterogeneity and lethality. Citation Format: Amy Bowes, Tom Lesluyes, Sara Waise, Annelien Verfaillie, Adrienne Flanagan, Jonas Demeulemeester, Maxime Tarabichi, Nischalan Pillay, Peter Van Loo. Profiling the evolutionary history of giant cancer cells in sarcomas: Hopeful monsters or an evolutionary dead end [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4340.