Endocrine Abstracts

Background: DNA methylation analysis has been proven useful biomarker in patients with colon (1-3), breast (4), and lung cancer (5). However, the clinical utility of this method in neuroendocrine neoplasms (NENs) is limited. Our research group has previously worked on the role of circulating cell-free tumour DNA (ctDNA) in neuroendocrine tumours (NETs) and thyroid cancers. Preliminary findings showed that this is a potentially useful clinical tool (6). We are expanding our research project to investigate the role of ctDNA methylation via nanopore sequencing in the detection and surveillance of NETs.

Subject and Methodology: We have already recruited patients 9 patients with NENs and will recruit more patients with germline mutation and unknown primary origin (total n-17). We are conducting this research with the collaboration of the genetics department of the University of Leicester. This is a retrospective, longitudinal, observational, pilot study.

DNA methylation analysis via nanopore sequencing: Methylation is a process that can silence the promotor areas of tumour suppressor genes and methylation of the gene itself can cause mutational events (7). Nanopore sequencing allows the investigation of methylation changes on a genome-wide level (8). The Ligation Sequencing Kit will be used to prepare the sheared DNA which will be loaded onto a MiniION Flow Cell. We will use the MinKNOW software to collect raw data from the device. The “REMORA” tool will be used for methylation analysis (9).

Conclusion: Successfully managing NENs relies on timely detection and diligent monitoring of treatment responses. We will investigate methylation analysis of the target genes identified in our group as pathogenically significant and to see if methylation of these and other genes are responsible for tumorigenesis in NENs. If successful, this work will progress to a larger comparative study to investigate the utility of ctDNA methylation analysis as a biomarker of neuroendocrine tumours.