Affiliations: Laboratory of Pharmacogenetics, University of Prince
Edward Island, Canada | Department of Environmental Studies, University of
Alexandria, Egypt | Department of Operative Dentistry, University of
Alexandria, Egypt
Note: [] Correspondence: Laboratory of Pharmacogenetics, University of
Prince Edward Island, 550 University Av., Charlottetown, PE, Canada C1A 4P3,
Tel: +1 902 566 0894, Fax: +1 902 566 0832, email: abadawi@upei.ca
Abstract: It has been suggested that nitrate and nitrite may play a role in
the etiology of human oral cancer. We investigated whether salivary nitrate and
nitrite and the activity of nitrate reductase (NRase) may affect the risk of
oral cancer in Egypt, an area with high levels of environmental nitrosating
agents. Levels of salivary nitrite (8.3 ± 1.0 µg/ml) and
nitrate (44 ± 3.7 µg/ml) and activity of NRase
(74 ± 10 nmol/ml/min) were significantly
(P < 0.05) higher in oral cancer patients (n = 42)
compared to control Egyptian healthy individuals (n = 40,
nitrite = 5.3 ± 0.3 µg/ml, nitrate =
27 ± 1.2 µg/ml, and NRase activity =
46 ± 4 nmol/ml/min). The adjusted odds ratio (OR) and the 95%
confidence intervals (C.I.) for risk of oral cancer, categorized by the levels
of salivary nitrate and nitrite and NRase activity, showed a higher cancer risk
associated with nitrite > 7.5 ìg/ml (OR: 3.0, C.I.:
1.09.3), nitrite > 40 ìg/ml (OR: 4.3, C.I.: 1.413.3)
and NRase activity > 50 nmol/ml/min (OR: 2.9, C.I.: 1.17.4). Our
findings suggest that increased consumption of dietary nitrate and nitrite is
associated with elevated levels of salivary nitrite. Together with the
increased activity of salivary NRase, these observations may explain, at least
in part, the role of nitrate and nitrite in the development of oral cancer in
individuals from an area with a high burden of N-nitroso precursors.
