Analysis of the p53 gene in relation to tobacco and alcohol in cancers of the upper aero-digestive tract

To elucidate the relationship, if any, of p53 gene expression according to smoking and drinking habits, 135 subjects with cancer of the upper aero-digestive tract were sampled from a case-control investigation conducted in Pordenone province Northeast Italy, between 1986 and 1991. Adequate pathological material for immunohistochemical analysis was available for 83 subjects. Level of p53 expression was classified according to intensity on immunoreaction and percentage of p53-positive cells. Mutations were analyzed by means of single-strand conformation polymorphism and sequencing in 8 p53-positive life-long non-smokers exposed to various levels of alcohol intake. The association between p53 expression and smoking status and alcohol intake was evaluated by means of odds ratios, and 95% confidence intervals. Significantly, more men (39/65) than women (6/18) had elevated p53 expression. No significant trend of increasing percentage of p53-positive cancers with increasing smoking and drinking level was detected, especially after allowance for gender. With respect to specific mutation pattern, in 8 life-long non smokers who drank alcohol, 6 mutations involved G:C base pairs. G-to-A transitions were identified in 4 cases. The present study does not support an association between elevated p53 expression and tobacco smoking or alcohol intake. It provides an example of a molecular biology study in the framework of a large epidemiological investigation.