Abstract Library

#3471 A novel in vitro spheroid model enables multi-modality assessment of the anti-tumoral immune response in pancreatic neuroendocrine neoplasms

Introduction: Patients harbouring pancreatic neuroendocrine neoplasms (PNENs) often present as a non-resectable disease due to distant metastases, hence, efficacy of the current medical intervention is limited. Activation of the mammalian target of rapamycin (mTOR) pathway is a known tumorigenic driver in PNENs. mTOR inhibition by Everolimus (EVE) delays PNEN progression, but the mechanism is not clear. EVE is also used as an immunosuppressant, thus we hypothesized that it may suppress the anti-tumoral immune response.

Conference:

Presenting Author:

Authors: Nasirov S, Zaig E, Mor-Cohen R, Telerman A, Tirosh A,

Keywords: PNEN, spheroid, Everolimus, mTOR,

#3387 High tissue expression of Flt3L is linked to higher infiltration of immune cells in patients with high-grade GEP-NEN

Introduction: The clinical management of gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) remains challenging due to disease heterogeneity. We have recently shown that mRNA expression of the immunostimulatory cytokine FMS-like tyrosine kinase 3 ligand (Flt3L) in tumor tissue is a prognostic biomarker in high-grade GEP-NEN patients. However, a direct link between Flt3L expression and the presence of proinflammatory immune cells in the tumor microenvironment (TME) of GEP-NEN is still missing.

Conference:

Presenting Author: Werner W

Authors: Werner W, Detjen K, Bruneau A, Wiedenmann B, Tacke F,

Keywords: NET, Flt3L, DC, dendritic cell, biomarker, immune response, immune microenvironment,

#3386 Peptide Radio Receptor Therapy induces immune activation in patients with neuroendocrine tumors and might sensitize to immunotherapy

Introduction: Peptide Radio Receptor Therapy (PRRT) is a standard treatment in patients with neuroendocrine tumors (NET), but treatment responses are limited and novel therapy combinations are needed. Since radiation induced cell death is considered immunogenic, patients might benefit from a combination of PRRT with immunotherapies, such as immune checkpoint inhibitors (ICI).

Conference:

Presenting Author: Büttner S

Authors: Büttner S, Detjen K, Galler M, Siefert J, Wiedenmann B,

Keywords: NET, PRRT, checkpoint inhibitors, immune response, PD1, flow cytometry,

#3323 Anti-immune defences involving down-regulation of MHC-I or beta-catenin activation do not explain immune coldness of pancreatic or ileal neuroendocrine tumors

Introduction: Our previous study demonstrated pancreatic (PNET) and ileal neuroendocrine tumors (INETs) are immunologically cold, containing very few tumor infiltrating lymphocytes (TILs) compared to non-small cell lung cancers. This raises the questions of whether there is in fact, a weak anti-tumor immune response taking place or whether the tumors are deploying effective anti-immune defences such as down-regulation of MHC class I or activation of β-catenin signalling.

Conference: 18th Annual ENETS Concerence (2021)

Presenting Author: Tanno L

Authors: Tanno L, Naheed S, Lopez M, Taylor J, Machado M,

Keywords: pancreatic neuroendocrine tumor, ileal neuroendocrine tumor, beta-catenin pathway, tumor immune microenvironment, major histocompatibility complex 1,

#3322 Analysis of immune landscape in pancreatic and ileal neuroendocrine tumors demonstrates an immune cold tumor microenvironment

Introduction: Neuroendocrine tumors (NETs) are rare tumors with an increasing incidence. While low and intermediate-grade pancreatic (PNET) and ileal (INET) tumors are slow-growing, they have a relatively high rate of metastasis to the liver where the outcome is much worse. For most cancers, the outcome is determined by the quality of the anti-tumor immune response. However, the quality and significance of anti-tumor responses in NETs are incompletely understood.

Conference: 18th Annual ENETS Concerence (2021)

Presenting Author:

Authors: Tanno L, Naheed S, Dunbar J, Tod J, Lopez M,

Keywords: pancreatic neuroendocrine tumor, ileal neuroendocrine tumor, tumor immune microenvironment, tumor infiltrating lymphocytes,