Background and study aims: Pancreatic cysts are common incidental findings, with an estimated prevalence of 13-15% in imaging done for other reasons. It is difficult to identify cysts with malignant potential. Diagnosis often relies on collection of cyst fluid, but tissue sampling using micro-forceps may allow for a more reliable diagnosis and higher yield of DNA for next-generation sequencing (NGS). Patients and methods: 24 patients referred for endoscopic ultrasound were recruited. Biopsies were taken using micro-forceps and the AmpliSeq Cancer Hotspot panel was used for NGS, a PCR assay targeting several hotspots within 50 genes, including GNAS, KRAS and VHL. Results: The concentration of DNA extracted from 24 cyst wall samples was significantly higher than in the 9/24 available matched cyst fluid samples. Cyst wall biopsy was able to diagnose 19/24 cysts (5 high risk, 6 intraductal papillary mucinous neoplasm and 4 benign). The sensitivity, specificity and diagnostic accuracy for standard of care was 66.6%, 50% and 63.1% respectively and for standard of care with NGS was 100%, 50% and 89.4% respectively. Conclusions: Cyst wall biopsy performs well in diagnosing cysts but was inadequate in 5/24 patients. NGS data correlates well with histology and may aid in diagnosis and risk stratification of pancreatic cysts.

The authors have declared no competing interest.

This work was funded by an Innovation Award from the NIHR Nottingham Biomedical Research Centre (BRC-1215-20003) to SA, JIG and SVV.

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Ethical approval was obtained from the Nottingham Health Science Biobank access committee (REC reference: 15/NW/0685, approval number: ACP000282). All work was carried out in accordance with the Declaration of Helsinki.

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Anonymised deep sequence data is available from the NCBI Sequence Read Archive under submission SUB11952288.