Abstract Library

#4505 NET-IMPRESS: A novel methylation-based assay to diagnose and monitor NET patients using liquid biopsies

Introduction: Previously, we showed that analysing copy number alterations (CNAs) in cell-free DNA (cfDNA) of NET patients using shallow whole genome sequencing (sWGS) is a potential biomarker for diagnosis and follow-up (PMID: 34759042). We now present NET-IMPRESS, an easy, cost-effective methylation-based assay for detecting circulating tumour DNA (ctDNA) in NET samples.

Conference:

Presenting Author:

Authors: Mariën L, Ibrahim J, de Meulenaere N, Chhajlani S, Neefs I,

Keywords: neuroendocrine tumour, liquid biopsy, DNA methylation, copy number alterations, biomarker selection, IMPRESS technology,

#4299 Defective DNA repair promotes progression of small intestinal neuroendocrine tumours despite a lack of common genomic drivers

Introduction: The tumorigenesis of small intestinal neuroendocrine tumours (siNETs) is not understood, despite being the most common form of small bowel cancer.

Conference:

Presenting Author: Bolduan F

Authors: Bolduan F, Müller-Bötticher N, Debnath O, Zemojtel T, Kunze C,

Keywords: small intestinal neuroendocrine tumour, pathogenetics, defective DNA repair,

#4289 Temozolomide-associated hypermutation and response to immunotherapy in advanced pulmonary neuroendocrine tumours

Introduction: Temozolomide (TMZ) cytotoxicity depends on an intact DNA mismatch repair (MMR) pathway and low levels of O6-methylguanine DNA methyltransferase (MGMT). However, absence of MGMT-mediated repair coupled with defective MMR (dMMR) may lead to enrichment of C:G to A:T transitions throughout the genome, a marked increase in tumour mutational burden (TMB), and loss of TMZ-induced cytotoxicity. This resistance mechanism is called TMZ-associated hypermutation (TAH). Theoretically, this effect could lead to sensitivity to checkpoint inhibitor immunotherapy.

Conference:

Presenting Author: Buikhuisen W

Authors: Buikhuisen W, Badrising S, Moonen L, Derks J, Monkhorst K,

Keywords: Pulmonary NET, whole genome sequencing, temozolomide signature, immunotherapy,

#4256 Epigenetic prediction of aging and metabolic traits provides insight into tumor biology in multi-focal ileal neuroendocrine tumors

Introduction: Approximately half of small intestinal neuroendocrine tumors (siNETs) are multifocal, and recent investigations into the genetic architecture of these tumors have found that they are not clonal. Due to the low mutational rate and slow growing nature of these small tumors, the ‘timing’ of the development of individual tumors has not been possible.

Conference:

Presenting Author:

Authors: Webster A, Makinen N, Ecker S, Beck S, Nakakura E,

Keywords: DNA methylation, Epigenetics, Multifocal Ileal Neuroendocrine Tumor, Multifocal Small Instestinal NET, Metabolic Traits,

#4174 Uncovering the genomic profiling of metastatic pheochromocytomas and paragangliomas: Leveraging plasma circulating tumor DNA for comprehensive genetic characterisation and monitoring

Introduction: Liquid biopsy, notably plasma circulating tumor DNA (ctDNA), is a non-invasive approach to elucidate the tumoral genomic profile from a blood sample. Pheochromocytomas and paragangliomas (PPGL) are often operated, characterized by quiet genomes and usually indolent tumor growth. However, challenges arise with metastatic tumors due to accessibility, catecholamine-related crises and surgery issues. Thus, molecular mechanisms transitioning from indolent to metastatic tumors are largely unexplored.

Conference:

Presenting Author:

Authors: Arenillas Lallana C, Moreno-Cárdenas A, Casteràs A, García-Álvarez A, Hernando J,

Keywords: liquid biopsy, ctDNA, metastasis, pheochromocytoma, paraganglioma, genomic targets,