Estimation of salivary nitric oxide in oral precancer patients

The role of nitric oxide (NO) in the initiation, promotion and progression of cancer has been the subject of speculation and conflicting reports in the literature. The high incidence of oral cancer and precancer has been linked to tobacco chewing and smoking habits; NO is considered an indicator of tobacco-related diseases. We compared salivary NO levels in oral precancer and normal patients. Unstimulated whole saliva was collected from 15 patients with oral precancer (group 1) and 15 healthy age and sex matched subjects (group 2). Salivary nitrite levels were estimated using a colorimetric method and a spectrophotometer. The salivary nitrite concentration of group 2 (median =4.21 mu g/ml) was significantly less than for group 1 (median =12.91 mu g/ml). We have added evidence concerning involvement of NO in the pathogenesis of oral cancer, but whether it is a potentially carcinogenic agent at the concentration at which it is present in oral precancer patients requires further evaluation.