TGFA and esophageal adenocarcinoma: Involvement of the Ras pathway in the early stages of neoplastic progression in Barrett's esophagus has been suggested by studies demonstrating genomic amplification or overexpression of the epidermal growth factor receptor (EGFR) and its ligand, transforming growth factor alpha (TGF-α), in biopsy samples of non-dysplastic Barrett's metaplasia [19], [20].