Assessment of tobacco specific nitrosamines (TSNAs) in oral fluid as biomarkers of cancer risk: A population-based study.
BACKGROUND
Smoke-free laws are expected to reduce smoking habits and exposure to secondhand smoke. The objective of this study was the measurement of tobacco specific carcinogens (TSNAs) in oral fluid to assess the most suitable biomarker of cancer risk associated with tobacco smoke.


METHODS
TSNAs, N'-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), as well as nicotine and cotinine were measured in oral fluid samples from 166 smokers and 532 non-smokers of the adult population of Barcelona, Spain. A simple method with an alkaline single liquid-liquid extraction with dichloromethane/isopropanol was used and lower limits of quantification for cotinine, NNN, NNK and NNAL were set at 0.10ng/mL, 1.0, 2.0 and 0.50pg/mL respectively. The NNN/cotinine ratio was also calculated.


RESULTS
NNN was the most abundant TSNA present in oral fluid with a significant difference between smokers and non-smokers (mean concentrations of 118 and 5.3pg/mL, respectively, p<0.001). NNK and NNAL were detectable in fewer samples. NNN and cotinine concentrations had a moderate correlation within both groups (Spearman's rank correlation coefficient of 0.312, p<0.001 in smokers and 0.279, p=0.022 in non-smokers). NNN/cotinine ratio was significantly higher (p<0.001) in non-smokers than in smokers, in line with equivalent findings for the NNAL/cotinine ratio in urine.


CONCLUSIONS
TSNAs are detectable in oral fluid of smokers and non-smokers. NNN is the most abundant, in line with its association with esophageal and oral cavity cancers. The NNN/cotinine ratio confirms the relative NNN increase in second hand smoke. Findings provide a new oral fluid biomarker of cancer risk associated with exposure to tobacco smoke.
Group of Integrative Pharmacology and Systems Neuroscience, Neurosciences Programme, IMIM (Hospital del Mar Medical Research Institute), Parc de Recerca Biomèdica de Barcelona, Doctor Aiguader 88, 08003 Barcelona, Spain; Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Doctor Aiguader, 88, 08003 Barcelona, Spain. Electronic address: rperez@imim.es.
Raúl
R
Pérez-Ortuño
Biostatistic Unit, Department of Basic Science, School of Medicine and Health Sciences, Universitat Internacional de Catalunya, Carrer Josep Trueta s/n, 08915 Sant Cugat del Valles, Barcelona, Spain; Tobacco Control Unit, Cancer Control and Prevention Programme, Institut Català d'Oncologia, WHO Collaborating Center for Tobacco Control, Av. Granvia de L'Hospitalet 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Control and Prevention Group, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Av. Granvia de L'Hospitalet 199-201, 08908 L'Hospitalet de Llobregat, Barcelona, Spain. Electronic address: jmmartinez@uic.es.
Jose M
JM
Martínez-Sánchez
Tobacco Control Unit, Cancer Control and Prevention Programme, Institut Català d'Oncologia, WHO Collaborating Center for Tobacco Control, Av. Granvia de L'Hospitalet 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Control and Prevention Group, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Av. Granvia de L'Hospitalet 199-201, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, School of Medicine, Universitat de Barcelona, Ctra. de la Feixa llarga s/n, 08907 L'Hospitalet del Llobregat, Barcelona, Spain. Electronic address: mfu@iconcologia.net.
Marcela
M
Fu
Tobacco Control Unit, Cancer Control and Prevention Programme, Institut Català d'Oncologia, WHO Collaborating Center for Tobacco Control, Av. Granvia de L'Hospitalet 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Control and Prevention Group, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Av. Granvia de L'Hospitalet 199-201, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, School of Medicine, Universitat de Barcelona, Ctra. de la Feixa llarga s/n, 08907 L'Hospitalet del Llobregat, Barcelona, Spain; Addictions Unit, Psychiatry Department, Institute of Neurosciences, Hospital Clínic de Barcelona, C. Villarroel 170, 08036 Barcelona, Spain. Electronic address: mballbe@iconcologia.net.
Montse
M
Ballbè
Tobacco Control Unit, Cancer Control and Prevention Programme, Institut Català d'Oncologia, WHO Collaborating Center for Tobacco Control, Av. Granvia de L'Hospitalet 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Control and Prevention Group, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Av. Granvia de L'Hospitalet 199-201, 08908 L'Hospitalet de Llobregat, Barcelona, Spain. Electronic address: nquiros@iconcologia.net.
Núria
N
Quirós
Tobacco Control Unit, Cancer Control and Prevention Programme, Institut Català d'Oncologia, WHO Collaborating Center for Tobacco Control, Av. Granvia de L'Hospitalet 199-203, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Cancer Control and Prevention Group, Institut d'Investigació Biomèdica de Bellvitge-IDIBELL, Av. Granvia de L'Hospitalet 199-201, 08908 L'Hospitalet de Llobregat, Barcelona, Spain; Department of Clinical Sciences, School of Medicine, Universitat de Barcelona, Ctra. de la Feixa llarga s/n, 08907 L'Hospitalet del Llobregat, Barcelona, Spain. Electronic address: efernandez@iconcologia.net.
Esteve
E
Fernández
Group of Integrative Pharmacology and Systems Neuroscience, Neurosciences Programme, IMIM (Hospital del Mar Medical Research Institute), Parc de Recerca Biomèdica de Barcelona, Doctor Aiguader 88, 08003 Barcelona, Spain; Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Parc de Recerca Biomèdica de Barcelona, Doctor Aiguader, 88, 08003 Barcelona, Spain. Electronic address: jpascual@imim.es.
José A
JA
Pascual
D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D002273:Carcinogens / Q000378:metabolism* / Q000633:toxicity; D016022:Case-Control Studies; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000209:etiology* / Q000378:metabolism; D009602:Nitrosamines / Q000032:analysis / Q000378:metabolism*; D012306:Risk; D012463:Saliva / Q000737:chemistry*; D012907:Smoking / Q000009:adverse effects / Q000378:metabolism*; D013030:Spain; D011795:Surveys and Questionnaires; D053719:Tandem Mass Spectrometry; D014026:Nicotiana
D015415:Biomarkers; D002273:Carcinogens; D009602:Nitrosamines
NNN; Saliva; TSNA; Tobacco biomarker; Tobacco carcinogen