Asian Pacific Journal of Cancer Prevention, Vol 8, 2007 229 Urinary Markers and Oral Cancer in India Asian Pacific J Cancer Prev, 8, 229-235 Introduction Oral cancer is one of the 10 most common cancers in the world. Tobacco products cause around 30% of all cancer death in developed countries (Peto et al.,1996). In spite of this, there are over one billion smokers in the world and millions of people who use smokeless tobacco products (Hatsukami and Severson, 1999; Pershagen, 1996). Exposure to environmental tobacco smoke is also a recognized cause of cancer (Benowitz, 1999). World health organization (WHO) has reported that about 90% of oral cancer in South-East Asia is attributed to use of tobacco. In India, oral cancer is highly prevalent, comprising 35-40% of all malignancies, due to the habit of tobacco chewing in betel quid commonly observed in the population (Daftary et al., 1991). Millions of people in India consume tobacco in various forms. Many individuals who do not consume tobacco are also exposed to tobacco smoke or smokeless tobacco products. These products contain thousands of chemical constituents including major alkaloid (nicotine) and minor alkaloids (noricotine, anabasine, anatabine etc.). These alkaloids can react with nitrite to form nitrosamines like Utility of Urinary Biomarkers in Oral Cancer Jayendra B Patel 1 , Shilin N Shukla 2 , Hiten RH Patel 3 , Kiran K Kothari 4 , Pankaj M Shah 5 , Prabhudas S Patel 1 * 1 Biochemistry Research Division, 2 Deputy Director (Research & Education), 3 Visiting Professor from University College Hospital, London, UK, 4 Surgical Oncology, 5 Director, The Gujarat cancer & Research Institute, Asarwa, Ahmedabad - 380 016, India *For correspondence: E-mail: prabhudas_p@hotmail.com, Fax #: 91 79 22685490 Abstract Objective: Oral cancer is the leading malignancy in India, with tobacco playing a major role in the etiology. The aim of the present study was to quantify nitrate+nitrite (NO2+NO3) in tobacco products as well as to study tobacco exposure related biomarkers in controls, patients with oral precancers (OPC) and oral cancer patients. Materials & Methods: Healthy individuals (n=90) were grouped into without habit of tobacco (NHT, n=30) and healthy individuals with habit of tobacco (WHT, n=60). Oral cancer patients with a tobacco habit were classified into abstinence (n=62) and non-abstinence (n=64) groups according to status at the study time. Urinary nicotine and cotinine levels were analyzed by modified high-pressure liquid chromatography (HPLC) using a UV detector. Levels of NO2+NO3 in tobacco and urine, and urinary thioether levels were estimated by spectrophotometry. Results: NO2+NO3 levels in different types of tobacco product ranged between 0.13 to 3.39 mg/g. The Odds Ratio (OR) analysis indicated positive associations of both smoking and chewing habits of tobacco with high risk of development of oral cancer. Urinary nicotine, cotinine and NO2+NO3 levels were significantly elevated in WHT, patients with OPC and oral cancer patients as compared with the NHT group. This was also the case for urinary thioether levels. Levels of urinary nicotine and cotinine were also higher in the non-abstinence group with oral cancers. Conclusion: The results confirmed that tobacco chewing and smoking habits are prominent risk factors for development of oral cancer in the western part of India (Gujarat). Urinary nicotine, cotinine, NO2+NO3 and thioether levels can be helpful for screening programs for oral cancer. Key Words: Tobacco - oral cancer/precancers - nicotine, cotinine, thioether and NO2+NO3 markers 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and 4-(methyl nitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), which are called tobacco specific nitrosamines. The components of nicotine, cotinine, nitrate and nitrite are important progenitors in the formation of tobacco specific nitrosamines (Hoffmann and Hecht, 1985). Nicotine, cotinine and NO2+NO3, the major constituents of tobacco products that are excreted in urine of tobacco-exposed individuals, can be used as the markers of tobacco exposure. Urinary nicotine and cotinine can be estimated by various methods including thin layer chromatography, high performance liquid chromatography (HPLC), gas chromatography and spectrophotometry. Urinary thioether levels can be also useful as biomarkers of tobacco exposure, because the tobacco exposure to electrophilic moieties increases thioether levels in urine (Bhisey et al., 1992). Urinary thioether levels are the index of total electrophilic burden in body. Such data from tobacco products and biological fluids can be helpful for development of preventive stragies. Therefore, aim of the study was to quantify NO2+NO3 in tobacco product and to assess role of tobacco habits as risk factors for development of oral RESEARCH COMMUNICATION