Abstract Library

#2991 Gastroenteropancreatic (GEP) Neuroendocrine Neoplasia G3 (NEN G3) According to 2019 WHO Classification: A Comprehensive Clinicopathological Characterization Including Mismatch Repair (MMR) Proteins, PDL1 Expression and KRAS/BRAF Status

Introduction: In the 2019 WHO FOR NEN’S classification NETG3 have been distinguished from poorly differentiated neuroendocrine carcinoma (NEC). They are heterogeneous group concerning prognosis and treatment benefit.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author:

Authors: Ruiz G, Graselli J, Golubicki M, Rizzol M,

Keywords: G3 NEN, PD-L1, KRAS, BIOMARKERS,

#2874 Role of FOXM1 in Aggressive Pancreatic / Pulmonary Neuroendocrine Carcinomas and Anti-Tumor Effect of the FOXM1 Inhibitor Thiostrepton

Introduction: DNA-targeting agents are the main treatment of aggressive pulmonary and pancreatic neuroendocrine carcinomas (NEC). FOXM1 is a transcription factor controlling cell proliferation and DNA repair pathways, playing therefore an important role in tumor progression and chemoresistance.

Conference: 17th Annual ENETSConcerence (2020)

Presenting Author: Cros J

Authors: De Rycke O, Raffenne J, Lacombe C, Hentic O, Gounant V,

Keywords: neuroendocrine carcinoma, FOXM1, DNA repair, anti-tumor drug,

#2280 The BON-SSTR2 Chicken Chorioallantoic Membrane (CAM) Model for the Analysis of Lu-17-DOTATOC Sensitizing Agents

Introduction: Peptide radioreceptor therapy (PRRT) is a promising therapy option for SSTR2-positive pancreatic neuroendocrine neoplasms (NEN). However, therapeutic effects are often not satisfying concerning sensitivity to PRRT. We hypothesize that the slow proliferation of NENs provides sufficient time for the repair of beta-particle induced-DNA damage. The ubiquitin-proteasome-system is involved in DNA damage repair and affected by the proteasome inhibitor bortezomib (Velcade®). The inhibition of DNA damage repair during PRRT may be an option to improve therapy response in NEN. We have recently demonstrated the damage repair inhibitory and pro-apoptotic effect of bortezomib in NEN in vitro (Briest et al., in revision).

Conference: 15th Annual ENETSConcerence (2018)

Presenting Author: Briest F

Authors: Briest F, Grötzinger C, Exner S, Sedding D, Baum R,

Keywords: peptide radioreceptor therapy, Lu-177-DOTATOC, PRRT, bortezomib, in vivo model, SPECT/CT Imaging, chicken CAM model, Sensitizer, DNA damage repair,

#2123 Large Cell Neuroendocrine Carcinoma (LCNEC) Associated with a Dysplastic Sessile Serrated Lesion (SSL) and Deficient Mismatch Repair (MMR) Protein: A Case Report.

Introduction: Colorectal poorly differentiated neuroendocrine carcinomas (NECs) are rare, but extremely aggressive. The mechanisms of their carcinogenesis and aggressiveness are still largely unknown. Recently Nobuyoshi Takizawa showed that the molecular features of colorectal NECs are similar to those of adenocarcinoma and not to those of NETs and they were more evident in small cell NECs than in large cell NECs. This is supported by combined cases with conventional adenoma/adenocarcinoma and NECs. Stelow et al showed that DNA mismatch repair proteins were intact in 14/15 colorectal small cell NECs. Two cases of LCNECs arising from SSL have been reported so far in the literature.

Conference: 15th Annual ENETSConcerence (2018)

Presenting Author: Luong T

Authors: Luong T, Nisa Z,

Keywords: Large cell neuroendocrine carcinoma, sessile serrated lesion, microsatellite instability, MMR protein, BRAF mutation,

#2101 The Effect of Temozolomide on Pancreatic Neuroendocrine Tumors in Vitro and Role of MGMT and MMR System in Temozolomide Resistance

Introduction: Temozolomide (TMZ) has been suggested as a treatment option for patients with pancreatic neuroendocrine tumours (PNETs). The tumour response to TMZ has been linked to expression levels of O6-methylguanine-DNA methyltransferase (MGMT) and components of the mismatch repair (MMR) system.

Conference: 15th Annual ENETSConcerence (2018)

Presenting Author: Blazevic A

Authors: Blazevic A, Dogan-Oruc F, Dedeci M, Van Koetsveld P, Feelders R,

Keywords: Pancreatic neuroendocrine tumors, Temozolomide, Cell lines, Tumor growth, O6-methylguanine-DNA methyltransferase (MGMT), Mismatch repair (MMR) system,