Detection of Advanced Neoplasia in Pancreatic Cysts by Assay of Novel DNA Methylation Markers in Cyst Fluid: A Multicenter Pilot Study: 2016 ACG Fellows-In-Training Award (Biliary/Pancreas Category)

Abstract

Introduction: An important subset of pancreatic cysts harbor advanced neoplasia (high-grade dysplasia (HGD) or cancer). Yet, current diagnostic approaches for detecting this high risk group are based on imaging criteria or cyst fluid analyses which lack accuracy. Management of patients with pancreatic cysts may be further optimized by molecular markers informative for advanced neoplasia. We have recently identified and validated a panel of novel methylated DNA markers (MDMs) in pancreatic tissue that discriminates HGD or adenocarcinoma from low-grade dysplasia (LGD) and non-dysplastic tissue1. It remains to be determined if this discrimination in tissue holds when applied to cyst fluid. In the present study, we aimed to assess and compare distributions of candidate MDMs in cyst fluid from cases with cysts containing advanced neoplasia and from controls with cysts containing either low-grade dysplasia (LGD) or no dysplasia. Methods: In this blinded multicenter study, archival pancreatic cyst fluid was identified from 83 surgically resected cysts. DNA from 0.2 ml cyst fluid was extracted and bisulfite converted. Assay of selected MDMs was then performed by methylation specific PCR; levels were normalized to beta actin (total DNA) and age. Cases (n=14) were cysts with adenocarcinoma or HGD and controls (n=61) were cysts with LGD or no dysplasia. Cysts with intermediate grade dysplasia (n=8) were analyzed separately. Results: The top 5 MDMs (BMP3, EMX1, CLEC11A, ST8IA1, VWC2) individually achieved areas under the ROC curve of ≥ 0.90 to distinguish cases from controls. Cyst fluid level distributions of the 2 top MDMs (BMP3, EMX1) illustrate the high discrimination (figure). At specificity of 90% (95% CI 80-96%), this 2 MDM panel detected 93% (66-100 %) of cases. MDM levels in cysts with intermediate grade dysplasia generally fell between HGD and LGD (figure); the 2 MDM panel would have called 38% of these lesions positive at 95% specificity. Conclusion: We demonstrate that assay of novel MDMs from pancreatic cyst fluid accurately distinguish cases with cancer or HGD from controls with LGD or no dysplasia. MDMs assayed from cyst fluid have potential to complement existing diagnostic approaches to improve predictive accuracy for pancreatic cysts at highest malignant risk. Further investigation and corroboration of these promising early results are needed.1Majumder S, et al. Gastroenterology 2016; S120-S121Figure 1