Background: Minimally invasive methods have been described to detect Barrett's esophagus (BE), but are limited by subjectivity and suboptimal accuracy. We identified methylated DNA markers (MDMs) for BE in tissue and assessed their accuracy on whole esophagus brushings and capsule sponge samples.
Methods: Step 1: Unbiased whole methylome sequencing was performed on DNA from BE and normal squamous esophagus (SE) tissue. Discriminant MDM candidates were validated on an independent patient cohort (62 BE cases, 30 controls) by quantitative methylation specific PCR (qMSP). Step 2: Selected MDMs were further evaluated on whole esophageal brushings (49 BE cases, 36 controls). 35 previously sequenced esophageal adenocarcinoma (EAC) MDMs were also evaluated. Step 3: 20 BE cases and 20 controls were randomized to swallow capsules sponges (25 mm, 10 pores or 20 pores per inch (ppi)) followed endoscopy. DNA yield, tolerability, and mucosal injury were compared. Best MDM assays were performed on this cohort.
Results: Step 1: 19 MDMs with areas under the ROC curve (AUCs) >0.85 were carried forward. Step 2: On whole esophageal brushings, 80% of individual MDM candidates showed high accuracy for BE (AUCs 0.84-0.94). Step 3: The capsule sponge was swallowed and withdrawn in 98% of subjects. Tolerability was superior with the 10 ppi sponge with minimal mucosal injury and abundant DNA yield. A 2-marker panel (VAV3 + ZNF682) yielded excellent BE discrimination (AUC = 1).
Conclusions: Identified MDMs discriminate BE with high accuracy. BE detection appears safe and feasible with a capsule sponge. Corroboration in larger studies is warranted. ClinicalTrials.gov number NCT02560623.