Barrett EsophagusPrecancerous ConditionsEsophagusMetaplasiaEsophageal NeoplasmsAdenocarcinomaGenes, MCCCardiaGastroesophageal RefluxEndoscopy, GastrointestinalEsophagoscopyDisease ProgressionImmunohistochemistryEsophagogastric JunctionEsophagectomyStomach NeoplasmsMucous MembraneHernia, HiatalEsophageal DiseasesPharmacy AdministrationBiopsyGastritis, AtrophicEndoscopyEsophageal StenosisCarcinoma, Squamous CellUterine Cervical NeoplasmsGastroscopyTumor Markers, BiologicalLeukoplakia, OralMouth NeoplasmsLeukoplakiaGastric Mucosa