GATA4 and gastroesophageal reflux disease: Our observation that human esophageal squamous epithelial cells respond to acid and bile by inducing GATA4 mRNA expression suggests that cells residing within the esophagus in vivo could similarly have the capacity to ectopically induce GATA4 expression in the presence of reflux, providing a possible link between chronic GERD and GATA4-expressing metaplastic cells.