Inclusion Criteria:

- Adults (> 18 years old)

- Subjects with pathologically confirmed Barrett's esophagus, including:

- Intestinal metaplasia without dysplasia, long and short segments (>1 cm)

- Intestinal metaplasia without dysplasia, long and short segments (>1 cm), previously
in GLNE 003

- Intestinal metaplasia without dysplasia with indefinite-for-dysplasia (or history of
indefinite-for-dysplasia) provided there is no history of HGD, or EAC.

- Intestinal metaplasia without dysplasia or indefinite-for-dysplasia with a history of
LGD provided the last surveillance endoscopy showed IM alone, the LGD history was at
least 12 or more months ago and there is no history of HGD or EAC.

- Able to physically tolerate removal of 34 ml of blood

- Tolerate extra research related biopsies and brushings

- Willing to permit extra biopsies at future endoscopic procedures

- Ability and willingness to complete questionnaires

- Willing to sign informed consent Exclusion Criteria

- Subjects with a pathologically confirmed history of Barrett's, HGD or EAC

- Subjects with pathologically confirmed history of Barrett's LGD within the last 12
months.

- Subjects in whom esophageal biopsy would be contraindicated (eq. varices)

- Subjects with serious infections requiring IV antibiotics

- Subjects with known HIV or chronic viral hepatitis

- Subjects on active chemotherapy or radiation treatment

- Subjects who have had an esophagectomy

- Subjects with an active malignancy diagnosed or treated within 3 years except for
squamous cell carcinoma of the skin, basal cell carcinoma of the skin; Carcinoma in
situ, Stages Ia or Ib invasive squamous cell carcinoma of the cervix treated by
surgery and/or radiation therapy; Stage Ia Grade 1 adenocarcinoma of the endometrium
treated with surgery