Abstract Library

#4545 Analysis of the mutational landscape of pancreatic neuroendocrine tumours before and after temozolomide treatment

Introduction: Temozolomide (TMZ) is an alkylating agent and standard treatment for pancreatic neuroendocrine tumours (pNET). Resistance to TMZ may be acquired through inactivation of the mismatch repair system, leading to high tumour mutation burden (hTMB).

Conference:

Presenting Author: Trevisani E

Authors: Trevisani E, Borghesani M, Reni A, Agnoletto C, Luchini C,

Keywords: neuroendocrine, next generation sequencing, temozolomide, hypermutation, tumour mutational burden,

#4417 Efficacy of immune checkpoint inhibitors (ICI) in patients with advanced pancreatic NETs displaying high TMB and MMR alterations following treatment with alkylating agents

Introduction: Alkylating chemotherapy (ALK) is frequently used in patients with PanNETs. It may favour grade progression and acquisition of a hypermutator phenotype associated with frequent alterations of the MMR genes, suggesting a potential benefit of ICI.

Conference:

Presenting Author:

Authors: de Mestier L, Apostolidis L, Koumarianou A, Hernando Cubero J, Riechelmann R,

Keywords: immune checkpoint inhibitor, immunotherapy, hypermutagenicity, alkylating agents, tumour mutational burden, mismatch repair,

#4386 Streptozotocin- and temozolomide-based chemotherapy treatment in neuroendocrine neoplasms – Efficacy in patients treated outside clinical trials

Introduction: Chemotherapy treatment based on alkylating agents is useful in pancreatic and grade 3 neuroendocrine neoplasms (NENs). However, no current real-life data is available comparing streptozotocin (STZ) and temozolomide (TEM) combinations.

Conference:

Presenting Author: García-Álvarez A

Authors: García Alvarez A, Martínez-Badal S, García-Burillo A, Simó Perdigo M, Merino Casabiel X,

Keywords: Streptozotocin, temozolomide, neuroendocrine neoplasm,

#4194 Temozolomide treatment induces an MMR-dependent hypermutator phenotype in well-differentiated pancreatic neuroendocrine tumors

Introduction: Temozolomide (TMZ), an alkylating agent, is an effective treatment used in multiple tumor types including advanced pancreatic neuroendocrine tumors (PanNET). In glioblastomas, TMZ induces a hypermutator and hyperprogressor phenotype in a subset of patients through MMR deficiency. In advanced colon cancer, TMZ priming increases tumor mutational burden (TMB), favouring immunotherapy efficacy.

Conference:

Presenting Author: de Mestier L

Authors: de Mestier L, Cohen D, de Rycke O, Masliah Planchon J, Fleischmann Z,

Keywords: temozolomide, hypermutation, pancreatic neuroendocrine tumor,

#4189 Pit and pitfalls of tumor mutational burden assessment in well-differentiated pancreatic neuroendocrine tumors: Two case reports from University of Verona

Introduction: The hypermutated phenotype is used as a predictive parameter for immune-checkpoint inhibitors (ICI). However, the relationship between high TMB, the underlying mutational drivers and response to ICI is still unclear.

Conference:

Presenting Author: Trevisani E

Authors: Torresan I, Reni A, Trevisani E, Borghesani M, Rossi A,

Keywords: Neuroendocrine tumor, NGS, Tumor Mutational Burden, Alkylating agent, DNA Damage Repair, Liquid biopsy,