Abstract PURPOSE: Rare cancers (<15 cases per 100,000 people/year) are poorly understood, particularly in Hispanic/Latinx populations. The My Pediatric and Adult Rare Tumor (MyPART) network conducts a Natural History Study of Rare Solid Tumors (NHSRT) to better understand rare tumor biology and develop effective therapeutic strategies. We analyzed NHSRT Hispanic/Latinx participants. METHODS: Patients of any age with rare solid tumors are eligible. All participants complete medical and family history forms, patient-reported outcomes (PRO) and provide saliva for DNA. Tumors undergo comprehensive molecular analysis and are discussed in a molecular tumor board. A subset of participants is invited to NIH Clinical Center (NIHCC) to undergo a clinical evaluation, genetic counseling, blood collection, and imaging studies, as indicated. Spanish-speaking participants are offered a medical interpreter. Forms are only available in English. RESULTS: Between January 2019 and December 2020, 16 of 200 participants identified as Hispanic/Latinx. Additionally, two international patients, a 15-year-old from Panama with Medullary Thyroid Carcinoma (MTC) who underwent total thyroidectomy with lymphadenectomy, and a 19-year-old from Mexico with Fibrolamellar Carcinoma (FLC) who underwent left hepatectomy and lymphadenectomy were enrolled later and received surgical treatment at NIHCC, which was not accessible in their home countries. Tumor types were neuroendocrine tumors (NET) (n=7), wild-type gastrointestinal stromal tumors (wt-GIST) (n=4), adrenocortical carcinoma (ACC) (n=1), MTC (n=3), and FLC (n=1). Two participants were relatives of patients with an SDHA mutation. Females accounted for 66% of the cohort; the median age was 35 years (range 15-69), enrolled from five US states and five countries. Nine patients used interpreter services. The median time from diagnosis to enrollment was 5.3 years. Half had metastatic disease at diagnosis. At enrollment, 57% of cases with local disease at diagnosis had progressed to metastasis, and 20% showed no evidence of disease. Twelve patients had successful tumor sequencing, and eight were found to have Pathogenic/Likely Pathogenic (Path/LP) variants. MEN1, SMAD4, and LZTR/RPS6KB2 in NET; SDHC in GIST; CDKN2B loss in ACC; DNAJB1-PRACA fusion in FLC; and RET mutations in MTC. Of 12 participants with germline mutation testing, Path/LP variants were found in 10, including SDHA, SDHC, and MUTYH in GIST patients and their relatives; PMS2 and RET in MTC; MEN1 and PALB2 in NET; SLC26A2, OTOF, XPC, and DNAH8 in ACC. CONCLUSION: Enrollment and comprehensive data collection were feasible, granting access to specialty care unavailable to several participants. Hispanic/Latinx representation was low, indicating recruitment challenges and the need for targeted strategies. Remote enrollment facilitated international participation. Making all forms available in Spanish is a priority. Ongoing analysis with over 500 NHRST participants will yield further insights. Citation Format: Juan C. Fierro Pineda, Shadin Ahmed, Karlyne Reilly, Robin Lockridge, Margarita Raygada, Barbara Thomas, John Glod, Abby Sandler, Brigitte Widemann, Mary Frances Wedekind Malone. Understanding rare cancers in Hispanic/Latinx populations: Insights from the MyPART natural history study of rare solid tumors [abstract]. In: Proceedings of the 16th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2023 Sep 29-Oct 2;Orlando, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2023;32(12 Suppl):Abstract nr C097.
Abstract In this study we aim to identify drugs that can be repurposed to inhibit malignant peripheral nerve sheath tumor (MPNST), a rare and deadly sarcoma associated with Neurofibromatosis type 1 (NF1). Inhibition of MPNST cell growth in vitro was tested for 30 drugs that have previously been through human clinical trials such that the maximum concentration of compound in human serum (Cmax) at the maximum tolerated dose has been determined. Drugs were compared to the chemotherapeutic doxorubicin. Six MPNST cell lines from human and mouse were tested and dose response curves were compared to Cmax for each drug. For most compounds tested, inhibition of MPNST viability occurred at drug concentrations higher than Cmax. Doxorubicin was one of the best compounds tested. Several compounds with less specific molecular targets appear promising, however, currently available inhibitors of receptor tyrosine kinase signaling pathways required concentrations above Cmax to inhibit MPNST viability. These data suggest that difficulty in developing therapy for MPNST may be due to the requirement for high concentrations of drugs to inhibit MPNST cells. Citation Format: Karlyne M. Reilly, Robert G. Tuskan, Brigitte C. Widemann. Comparison of the dose response of malignant peripheral nerve sheath tumor in vitro growth inhibition of 30 drugs to reported Cmax values [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 5038. doi:10.1158/1538-7445.AM2017-5038
<div>Abstract<p>Malignant peripheral nerve sheath tumors (MPNST) are soft-tissue sarcomas that are the leading cause of mortality in patients with Neurofibromatosis type 1 (NF1). Single chemotherapeutic agents have shown response rates ranging from 18% to 44% in clinical trials, so there is still a high medical need to identify chemotherapeutic combination treatments that improve clinical prognosis and outcome. We screened a collection of compounds from the NCATS Mechanism Interrogation PlatE (MIPE) library in three MPNST cell lines, using cell viability and apoptosis assays. We then tested whether compounds that were active as single agents were synergistic when screened as pairwise combinations. Synergistic combinations <i>in vitro</i> were further evaluated in patient-derived orthotopic xenograft/orthoxenograft (PDOX) athymic models engrafted with primary MPNST matching with their paired primary-derived cell line where synergism was observed. The high-throughput screening identified 21 synergistic combinations, from which four exhibited potent synergies in a broad panel of MPNST cell lines. One of the combinations, MK-1775 with Doxorubicin, significantly reduced tumor growth in a sporadic PDOX model (MPNST-SP-01; sevenfold) and in an NF1-PDOX model (MPNST-NF1–09; fourfold) and presented greater effects in <i>TP53</i> mutated MPNST cell lines. The other three combinations, all involving Panobinostat (combined with NVP-BGT226, Torin 2, or Carfilzomib), did not reduce the tumor volume <i>in vivo</i> at noncytotoxic doses. Our results support the utility of our screening platform of <i>in vitro</i> and <i>in vivo</i> models to explore new therapeutic approaches for MPNSTs and identified that combination MK-1775 with Doxorubicin could be a good pharmacologic option for the treatment of these tumors.</p></div>
Supplementary Table 2 from The Neurofibromatosis Type 1 Tumor Suppressor Controls Cell Growth by Regulating Signal Transducer and Activator of Transcription-3 Activity <i>In vitro</i> and <i>In vivo</i>
Oncolytic virus therapy is being evaluated in clinical trials for human glioma. While it is widely assumed that the immune response of the patient to the virus infection limits the utility of the therapy, investigations into the specific cell type(s) involved in this response have been performed using nonspecific pharmacologic inhibitors or allogeneic models with compromised immunity. To identify the immune cells that participate in clearing an oncolytic infection in glioma, we used flow cytometry and immunohistochemistry to immunophenotype an orthotopic glioma model in immunocompetent mice after Myxoma virus (MYXV) administration. These studies revealed a large resident microglia and macrophage population in untreated tumors, and robust monocyte, T-, and NK cell infiltration 3 days after MYXV infection. To determine the role on the clinical utility of MYXV therapy for glioma, we used a combination of knockout mouse strains and specific immunocyte ablation techniques. Collectively, our experiments identify an important role for tumor-resident myeloid cells and overlapping roles for recruited NK and T cells in the clearance and efficacy of oncolytic MYXV from gliomas. Using a cyclophosphamide regimen to achieve lymphoablation prior and during MYXV treatment, we prevented treatment-induced peripheral immunocyte recruitment and, surprisingly, largely ablated the tumor-resident macrophage population. Virotherapy of cyclophosphamide-treated animals resulted in sustained viral infection within the glioma as well as a substantial survival advantage. This study demonstrates that resistance to MYXV virotherapy in syngeneic glioma models involves a multifaceted cellular immune response that can be overcome with cyclophosphamide-mediated lymphoablation.
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