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Purpose of Review: This study aims to present the current landscape of immunotherapy in the management of small bowel neuroendocrine tumors and identify ongoing and future targets for improved response. Recent Findings: Somatostatin analogs and mTOR inhibitors remain cornerstones of non-surgical treatment, and applications of PRRT in SBNET are promising. Several efforts to replicate the success of immunotherapies in other solid tumors have been attempted in SBNET, with limited responses observed with current immune targets, such as PD-1/PD-L1 and CTLA-4. Epigenetic analyses have suggested a potential role for methylation and histone acetylation in SBNET tumorigenesis that warrant greater exploration. Summary: While the incidence of SBNET continues to increase, the number of effective therapies is few. Further elucidation of targetable components of the SBNET immune microenvironment with greater modulatory effects is necessary to improve outcomes in this growing patient population. [ABSTRACT FROM AUTHOR]

Despite recent advances in the systemic treatment of gastrointestinal tumors, pancreatic adenocarcinoma (PDAC) remains a challenging disease, with 5‐year survival just over 10%. Pancreatectomy in patients meeting defined anatomic criteria can result in cure; however, perioperative morbidity and mortality, as well as high rates of both local and distant recurrence even after "potentially curative" resection, have limited survival. Although perioperative chemotherapy has been shown to improve patients' longevity and chance for cure, debate continues about whether the preoperative or adjuvant approach is most effective in treatment of localized PDAC. Large, randomized multicenter trials in patients with resectable and borderline resectable PDAC have evaluated an evolving therapeutic landscape with mixed results. Importantly, these landmark studies share the fundamentally flawed assumption that tumor anatomical characteristics are an indicator of behavior and natural history. Concurrent biologic and translational research has revealed that rather than a single disease, PDAC represents a phenotypically variable group of malignancies arising in physiologically diverse patients. Ongoing novel trials have begun to capture this heterogeneity both in patient selection as well as the measurement of response by using genomic, transcriptional and radiomic markers. By moving away from classic anatomic descriptors to a more nuanced landscape of biomarkers predictive of tumor behavior and response, we can further refine the questions asked in preoperative trials and translate the answers to clinically meaningful precision therapy in localized PDAC. The concurrent evolution of perioperative therapy, surgery and multidisciplinary care have resulted in hard‐fought gains in survival for patients with pancreatic cancer. In the management of localized PDAC, the focus on classic anatomic descriptors of tumor resectability must yield to a more nuanced focus on biomarkers of cancer behavior and response. [ABSTRACT FROM AUTHOR]

Background: Patients with metastatic sarcomas have poor outcomes and although the disease may be amenable to immunotherapies, information regarding the immunologic profiles of soft tissue sarcoma (STS) subtypes is limited.Methods: The authors identified patients with the common STS subtypes: leiomyosarcoma, undifferentiated pleomorphic sarcoma (UPS), synovial sarcoma (SS), well-differentiated/dedifferentiated liposarcoma, and myxoid/round cell liposarcoma. Gene expression, immunohistochemistry for programmed cell death protein (PD-1) and programmed death-ligand 1 (PD-L1), and T-cell receptor Vβ gene sequencing were performed on formalin-fixed, paraffin-embedded tumors from 81 patients. Differences in liposarcoma subsets also were evaluated.Results: UPS and leiomyosarcoma had high expression levels of genes related to antigen presentation and T-cell infiltration. UPS were found to have higher levels of PD-L1 (P≤.001) and PD-1 (P≤.05) on immunohistochemistry and had the highest T-cell infiltration based on T-cell receptor sequencing, significantly more than SS, which had the lowest (P≤.05). T-cell infiltrates in UPS also were more oligoclonal compared with SS and liposarcoma (P≤.05). A model adjusted for STS histologic subtype found that for all sarcomas, T-cell infiltration and clonality were highly correlated with PD-1 and PD-L1 expression levels (P≤.01).Conclusions: In the current study, the authors provide the most detailed overview of the immune microenvironment in sarcoma subtypes to date. UPS, which is a more highly mutated STS subtype, provokes a substantial immune response, suggesting that it may be well suited to treatment with immune checkpoint inhibitors. The SS and liposarcoma subsets are less mutated but do express immunogenic self-antigens, and therefore strategies to improve antigen presentation and T-cell infiltration may allow for successful immunotherapy in patients with these diagnoses. Cancer 2017;123:3291-304. © 2017 The Authors. Cancer published by Wiley Periodicals, Inc. on behalf of American Cancer Society. This is an open access article under the terms of the Creative Commons Attribution NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. [ABSTRACT FROM AUTHOR]

Pancreatic ductal adenocarcinoma (PDA) remains a deadly disease that is rarely cured, despite many recent successes with immunotherapy for other malignancies. As the human disease is heavily infiltrated by effector T cells, we postulated that accurately modeling the PDA immune microenvironment would allow us to study mechanisms of immunosuppression that could be overcome for therapeutic benefit. Using viable precision-cut slices from fresh PDA, we developed an organotypic culture system for this purpose. We confirmed that cultured slices maintain their baseline morphology, surface area, and microenvironment after at least 6 d in culture, and demonstrated slice survival by MTT assay and by immunohistochemistry staining with Ki-67 and cleaved-Caspase-3 antibodies. Immune cells, including T cells (CD3+, CD8+, and FOXP3+) and macrophages (CD68+, CD163+and HLA-DR+), as well as stromal myofibroblasts (αSMA+) were present throughout the culture period. Global profiling of the PDA proteome before and after 6 d slice culture indicated that the majority of the immunological proteins identified remain stable during the culture process. Cytotoxic effects of drug treatment (staurosporine, STS and cycloheximide, CHX) on PDA slices culture confirmed that this system can be used to assess functional response and cell survival following drug treatment in both a treatment time- and dose-dependent manner. Using multicolor immunofluorescence, we stained live slices for both cancer cells (EpCAM+) and immune cells (CD11b+and CD8+). Finally, we confirmed that autologous CFSE-labeled splenocytes readily migrate into co-cultured tumor slices. Thus, our present study demonstrates the potential to use tumor slice cultures to study the immune microenvironment of PDA. [ABSTRACT FROM PUBLISHER]