Utility of urinary biomarkers in oral cancer.

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.

Biological monitoring of environmental exposure to mutagens among high school students in Jeddah

Mutagenic and/or carcinogenic substances, which are present in the environment, are numerous. They include electrophilic compounds, polycyclic aromatic compounds such as benzo [a] pyrene which is a polyaromatic hydrocarbon. It is well known to be mutagenic and carcinogenic. Biological monitoring that depends on estimating a substance or one of its metabolites or one of its effective components in biological fluids such as urine and blood was carried out. Thioether concentration in urine indicates absorption of mutagenic and/or carcinogenic substances. Thiocyanates concentration in urine was used as an indicator of absorption of mutagenic and/or carcinogenic haloacetonitriles. Urinary cotinine was used to estimate the extent of exposure to tobacco smoke, the heaviness of smoking, and whether the subject is smoker or not. Three hundreds and thirty two male students were randomly selected from eight secondary schools in Jeddah city. Their ages were more than 15 years and they were apparently free from illness. Every student filled a questionnaire. Random urine samples were obtained from all students. Thioether, thiocyanate, cotinine, and creatinine were measured in urine samples. There was a direct relation between urinary thioether and each of smoking index, food index, urinary thiocyanate, and cotinine. Urinary thioether shows an inverse relation with BMI. Urinary thiocyanate and cotinine showed direct relation with smoking index and with each of them and the other factor. This indicates interference between these indices and smoking is still one of the most misleading factors in researches that deal with the mutagenic and/or carcinogenic effects in the environment