title: Quantitative detection of p53 mutations in plasma DNA from tobacco smokers.
abstract: In lung tumors, the p53 tumor suppressor gene is commonly mutated with a characteristic mutation spectrum. The amount of and alterations in plasma DNA, such as mutations in p53, were associated with several cancers. Few studies used quantitative methods of high sensitivity. Previously, we observed p53 mutations in the noncancerous tissue that differed from those in lung tumors using the highly sensitive p53 mutation load assay. Based on our observation of an increased p53 mutation load in nontumorous lung tissue in smokers, we hypothesized that plasma DNA may contain mutant p53 indicative of tobacco smoke exposure and will be an effective biomarker of lung cancer or smoking exposure. We modified the p53 mutation load assay to detect mutations at p53 codons 248 and 249, common mutations in lung cancer, in plasma DNA samples with a sensitivity of 1:5,000. The assay was applied to a set of lung cancer cases (n = 39), hospital controls (n = 21), and population controls (n = 20) from a larger study. Controls were selected to consist of equal numbers of both ever and never smokers. The p53 mutation load (mutated p53 copies per total number of p53 copies) was associated with smoking (P = 0.06), but not with lung cancer (P = 0.59). Most of the individuals with p53 mutations observed in plasma DNA were ever smokers and the p53 mutation load was higher in those who smoked for longer durations (P = 0.04). In summary, we were able to detect p53 mutations in plasma DNA from healthy individuals and our data suggest that p53 mutations in plasma DNA may be a marker of carcinogen exposure from tobacco smoke.
authors.affiliation: Laboratory of Human Carcinogenesis, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892-4258, USA.
authors.forename: Nobutoshi
authors.initials: N
authors.lastname: Hagiwara
authors.forename: Leah E
authors.initials: LE
authors.lastname: Mechanic
authors.forename: Glenwood E
authors.initials: GE
authors.lastname: Trivers
authors.forename: Helen L
authors.initials: HL
authors.lastname: Cawley
authors.forename: Masataka
authors.initials: M
authors.lastname: Taga
authors.forename: Elise D
authors.initials: ED
authors.lastname: Bowman
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kumamoto
authors.forename: Peijun
authors.initials: P
authors.lastname: He
authors.forename: Mark
authors.initials: M
authors.lastname: Bernard
authors.forename: Saira
authors.initials: S
authors.lastname: Doja
authors.forename: Masao
authors.initials: M
authors.lastname: Miyashita
authors.forename: Takashi
authors.initials: T
authors.lastname: Tajiri
authors.forename: Koji
authors.initials: K
authors.lastname: Sasajima
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nomura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Makino
authors.forename: Ken
authors.initials: K
authors.lastname: Takahashi
authors.forename: S Perwez
authors.initials: SP
authors.lastname: Hussain
authors.forename: Curtis C
authors.initials: CC
authors.lastname: Harris
mesh_terms: D015142:Baltimore / Q000453:epidemiology; D002460:Cell Line; D004247:DNA / Q000097:blood* / Q000235:genetics / Q000302:isolation & purification; D016158:Genes, p53; D006801:Humans; D008175:Lung Neoplasms / Q000453:epidemiology / Q000209:etiology / Q000235:genetics*; D009154:Mutation; D016133:Polymerase Chain Reaction; D012907:Smoking / Q000097:blood* / Q000235:genetics*
chemical_list: D004247:DNA