Individuals with one aerodigestive tract malignancy have a high incidence of second primary aerodigestive @entity5 . The mechanism for this field effect has not been determined. We studied an individual with widespread dysplastic changes in the respiratory epithelium but no overt @entity189 . The entire tracheobronchial tree obtained at autopsy was embedded in paraffin, and bronchial epithelial cells were isolated by microdissection. DNA extracted from the microdissected cells was analyzed for point mutations in the @entity876 @entity5 suppressor gene. A single, identical point mutation consisting of a G:C to T:A transversion in codon 245 was identified in bronchial epithelium from 7 of 10 sites in both lungs. Epithelium at sites containing the @entity876 mutation was morphologically abnormal, exhibiting @entity1544 and mild to moderate atypia. No invasive @entity5 was found in the tracheobronchial tree or any other location. Cells from peripheral blood, kidney, liver, and lymph node exhibited no abnormality in the @entity876 gene. The widespread presence of a single somatic @entity876 point mutation in the bronchi of a smoker suggests that a single progenitor bronchial epithelial clone may expand to populate broad areas of the bronchial mucosa-a novel mechanism for field @entity105 in the respiratory epithelium that may be of importance in assessing individuals for risk of a second @entity5 as well as in devising effective strategies for chemoprevention of @entity2 .

Widely dispersed @entity876 mutation in respiratory epithelium. A novel mechanism for field XXXX .

@entity5 :: ('MESH:D009369', 'Disease') :: ['tumor', 'primary tumor', 'tumors'] @entity2 :: ('MESH:D008175', 'Disease') :: ['lung cancer'] @entity189 :: ('MESH:D002277', 'Disease') :: ['carcinoma'] @entity876 :: ('7157', 'Gene') :: ['p53'] @entity1544 :: ('MESH:D018307', 'Disease') :: ['squamous metaplasia'] @entity105 :: ('MESH:D063646', 'Disease') :: ['carcinogenesis']
@entity105 :: (MESH:D063646,Disease) :: ['carcinogenesis']
