[Gastroscopic biopsy in the diagnosis of tumors of the upper gastrointestinal tract].
D001706:Biopsy / Q000379:methods*; D004938:Esophageal Neoplasms / Q000473:pathology*; D005773:Gastroscopy; D006801:Humans; D013274:Stomach Neoplasms / Q000473:pathology*