title: Quantitative analysis of plasma TP53 249Ser-mutated DNA by electrospray ionization mass spectrometry.
abstract: A mutation in codon 249 of the TP53 gene (249(Ser)), related to aflatoxin B(1) exposure, has previously been associated with hepatocellular carcinoma risk. Using a novel internal standard plasmid, plasma concentrations of 249(Ser)-mutated DNA were quantified by electrospray ionization mass spectrometry in 89 hepatocellular carcinoma cases, 42 cirrhotic patients, and 131 nonliver diseased control subjects, all from highly aflatoxin-exposed regions of The Gambia. The hepatocellular carcinoma cases had higher median plasma concentrations of 249(Ser) (2,800 copies/mL; interquartile range: 500-11,000) compared with either cirrhotic (500 copies/mL; interquartile range: 500-2,600) or control subjects (500 copies/mL; interquartile range: 500-2,000; P < 0.05). About half (52%) of the hepatocellular carcinoma cases had >2,500 copies of 249(Ser)/mL plasma, corresponding to the prevalence of this mutation in liver tumors in The Gambia. In comparison, only 15% of control group and 26% of cirrhotic participants exceeded this level (P < 0.05). Further subset analysis revealed a statistically significant, quantitative relation between diagnosis of hepatocellular carcinoma and levels of 249(Ser) detected at 2,501 to 10,000 copies/mL plasma (odds ratio, 3.8; 95% confidence interval, 1.3-10.9) and at >10,000 copies/mL plasma (odds ratio, 62; 95% confidence interval, 4.7-820) when compared with control subjects and after adjusting for age, gender, recruitment site, hepatitis B and C serologic status, and total DNA concentration. Levels of >10,000 copies of 249(Ser)/mL plasma were also significantly associated with the diagnosis of hepatocellular carcinoma (odds ratio, 15; 95% confidence interval, 1.6-140) when compared with cirrhotic patients. Potential applications for the quantification of 249(Ser) DNA in plasma include estimation of long-term, cumulative aflatoxin exposure and selection of appropriate high-risk individuals for targeted intervention.
authors.affiliation: Johns Hopkins Bloomberg School of Public Health, Department of Environmental Health Sciences, 615 North Wolfe Street, Room E7032, Baltimore, MD 21205, USA. mfriesen@jhsph.edu
authors.forename: Matilde E
authors.initials: ME
authors.lastname: Lleonart
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Kirk
authors.forename: Stephanie
authors.initials: S
authors.lastname: Villar
authors.forename: Olufunmilayo A
authors.initials: OA
authors.lastname: Lesi
authors.forename: Abhijit
authors.initials: A
authors.lastname: Dasgupta
authors.forename: James J
authors.initials: JJ
authors.lastname: Goedert
authors.forename: Maimuna
authors.initials: M
authors.lastname: Mendy
authors.forename: Monica C
authors.initials: MC
authors.lastname: Hollstein
authors.forename: Ruggero
authors.initials: R
authors.lastname: Montesano
authors.forename: John D
authors.initials: JD
authors.lastname: Groopman
authors.forename: Pierre
authors.initials: P
authors.lastname: Hainaut
authors.forename: Marlin D
authors.initials: MD
authors.lastname: Friesen
mesh_terms: D000348:Aflatoxins / Q000633:toxicity; D006528:Carcinoma, Hepatocellular / Q000097:blood / Q000235:genetics*; D016022:Case-Control Studies; D004273:DNA, Neoplasm / Q000097:blood*; D005260:Female; D005714:Gambia; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000235:genetics*; D008113:Liver Neoplasms / Q000097:blood / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors; D021241:Spectrometry, Mass, Electrospray Ionization; D016159:Tumor Suppressor Protein p53 / Q000097:blood*
chemical_list: D000348:Aflatoxins; D004273:DNA, Neoplasm; D016159:Tumor Suppressor Protein p53