Precancerous Conditions: Pathological processes that tend eventually to become malignant. (From Dorland, 27th ed)Oral Submucous FibrosisAnemia, Pernicious: A megaloblastic anemia occurring in children but more commonly in later life, characterized by histamine-fast achlorhydria, in which the laboratory and clinical manifestations are based on malabsorption of vitamin B 12 due to a failure of the gastric mucosa to secrete adequate and potent intrinsic factor. (Dorland, 27th ed)Mouth Neoplasms: Tumors or cancer of the MOUTH.Stomach Neoplasms: Tumors or cancer of the STOMACH.Metaplasia: A condition in which there is a change of one adult cell type to another similar adult cell type.Gastritis, Atrophic: GASTRITIS with atrophy of the GASTRIC MUCOSA, the GASTRIC PARIETAL CELLS, and the mucosal glands leading to ACHLORHYDRIA. Atrophic gastritis usually progresses from chronic gastritis.Uterine Cervical Neoplasms: Tumors or cancer of the UTERINE CERVIX.Leukoplakia, Oral: A white patch seen on the oral mucosa. It is considered a premalignant condition and is often tobacco-induced. When evidence of Epstein-Barr virus is present, the condition is called hairy leukoplakia (LEUKOPLAKIA, HAIRY).Leukoplakia: A white patch lesion found on a MUCOUS MEMBRANE that cannot be scraped off. Leukoplakia is generally considered a precancerous condition, however its appearance may also result from a variety of HEREDITARY DISEASES.Colposcopes: Instruments inserted into the vagina for examination of the tissues of the vagina and cervix by means of a magnifying lens.Gastroscopy: Endoscopic examination, therapy or surgery of the interior of the stomach.Aberrant Crypt Foci: Clusters of colonic crypts that appear different from the surrounding mucosa when visualized after staining. They are of interest as putative precursors to colorectal adenomas and potential biomarkers for colorectal carcinoma.