title: Using tissue adjacent to carcinoma as a normal control: an obvious but questionable practice.
abstract: When carcinoma tissue is investigated using biochemical, immunohistochemical, and genetic techniques, adjacent tissue that is macroscopically normal is frequently used as a control, since cancer-related pheno- and geno-typic alterations are assumed to be absent. However, a field that contains genetically abnormal cells surrounds a significant proportion of carcinomas (for example, over 30% of head and neck cancers). These fields can be large (>7 cm in diameter) and consist of cells that are clonally related to the carcinoma. This indicates that adjacent epithelium must be checked for genetic abnormalities before it is considered normal and used as a control for comparison with carcinoma.
authors.affiliation: Department of Otolaryngology/Head and Neck Surgery, Vrije Universiteit Medical Center, PO Box 7057, 1007 MB Amsterdam, The Netherlands. bjm.braakhuis@vumc.nl
authors.forename: Boudewijn J M
authors.initials: BJ
authors.lastname: Braakhuis
authors.forename: C René
authors.initials: CR
authors.lastname: Leemans
authors.forename: Ruud H
authors.initials: RH
authors.lastname: Brakenhoff
mesh_terms: D014408:Biomarkers, Tumor; D004848:Epithelium / Q000473:pathology; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D009369:Neoplasms / Q000235:genetics / Q000473:pathology*; D011230:Precancerous Conditions / Q000235:genetics / Q000473:pathology*; D012107:Research Design
chemical_list: D014408:Biomarkers, Tumor; D005819:Genetic Markers