Novel Biomarkers in the Neoplastic Progression of Barrett's Esophagus

Patients with Barrett's esophagus (BE) have an increased risk of esophageal adenocarcinoma which is 40-125 fold higher than in the general population. However, the current techniques of detecting dysplasia and observing abnormal p53 immunohistochemical staining are not accurate or reliable methods for determining which BE patients will progress to cancer. DNA hypermethylation is an epigenetic process that occurs in the promoter region of certain genes, resulting in suppression of gene expression. Inactivation of specific genes via hypermethylation has been highly associated with cancer. The primary objective of this research is to determine whether DNA hypermethylation is a biomarker that will predict which patients with BE are likely to progress to adenocarcinoma. Patients with BE and/or esophageal adenocarcinoma who undergo endoscopy at the Johns Hopkins Hospital will comprise the cohort of subjects. Gene hypermethylation will be assessed by performing methylation-specific Polymerase Chain Reaction (PCR) on a panel of 8 cancer-related genes. Specific Aim 1: To compare the prevalence of gene hypermethylation in BE patients with different grades of dysplasia and/or adenocarcinoma, using archived specimens. Specific Aim 2: To determine whether the presence of gene hypermethylation in initial biopsies of BE patients is associated with progression to adenocarcinoma, using archived specimens. To compare gene hypermethylation with currently available markers for neoplastic progression. Specific Aim 3: To determine whether methylated DNA from BE and/or adenocarcinoma can be detected in the peripheral blood of patients, by comparing methylation profiles of esophageal biopsy specimens with peripheral blood samples taken at the same time in prospectively enrolled patients. If hypermethylation of one or more genes is detected at an early stage in BE patients who later progress to adenocarcinoma, hypermethylation could be used as an early predictor for adenocarcinoma even before pathologic changes are evident. Furthermore, this research will help determine the specific genetic events that occur in the neoplastic transformation from BE to adenocarcinoma. The long-term goal of this project is to determine whether hypermethylation can identify BE patients who are at high risk for neoplastic progression, thus allowing for early intervention in the form of more frequent endoscopic surveillance, chemoprevention, ablative therapy, or surgery.