MetaplasiaEsophagusAdenocarcinomaPrecancerous ConditionsEsophagoscopyGenes, MCCPharmacy AdministrationCardiaHernia, HiatalGastroesophageal RefluxEndoscopy, GastrointestinalEsophagogastric JunctionMucous MembraneEsophagectomyChromosomes, Human, Pair 5EndoscopyChromosomes, Human, Pair 17Loss of HeterozygosityBiopsyDisease ProgressionImmunohistochemistryTumor Markers, BiologicalStomach NeoplasmsGene Expression Regulation, NeoplasticPolymerase Chain ReactionPrognosisRisk FactorsBarrett Esophagus