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,

#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,

#1845 Mismatch Repair (MMR) Protein Expression is Uncommon in Poorly Differentiated Neuroendocrine Carcinoma

Introduction: Microsatellite instability (MSI) has been reported to occur in a significant proportion of neuroendocrine carcinoma (NEC) and mixed adenoneuroendocrine carcinomas (MANEC) (11 out of 89 cases, Sahnane et al, ERC 2015). It might be predictive of response to immunotherapy.

Conference: 14th Annual ENETSConcerence (2017)

Presenting Author: Hadoux J

Authors: Hadoux J, Malka D, Berdeloux A, Planchard D, Boige V,

Keywords: Neuroendocrine carcinoma, mismatch repair, microsatellite instability,

#174 Loss of Expression of the DNA Mismatch Repair Proteins MLH1 and MSH2 is Rare in Pancreatic and Small Intestinal Neuroendocrine Tumors

Introduction: Loss of expression of the DNA mismatch repair (MMR) proteins MLH1 and MSH2, which is known to correlate strongly with MSI, has not been well studied in pancreatic or small intestinal NETs.

Conference: 8th Annual ENETSConcerence (2011)

Presenting Author:

Authors: Rayson D, Arnason T, Sapp H, Barnes P, Drewniak M,

Keywords: microsatellite instability, tissue microarray, pnets, small intestinal nets,