A MOLECULAR AND EPIDEMIOLOGIC-STUDY ON BLADDER-CANCER - P53 MUTATIONS, TOBACCO SMOKING, AND OCCUPATIONAL EXPOSURE TO ASBESTOS

In this study, we found an unexpected association (crude odds ratio = 2.8; 95% confidence interval = 0.9-8.4) between definite work-related exposure to asbestos and carcinoma of the urinary bladder in a small g roup of patients (n = 28) initially recruited as referents for an epid emiological feasibility study on the occupational causes of lung cance r. We extended the study by using molecular methods to examine mutatio ns in the p53 tumor suppressor gene in the same cases of bladder cance rs. The same number of archival samples of transitional cell carcinoma , mainly of grade 3, were added to the analysis. We failed to show any association between occupational exposure to asbestos and p53 mutatio ns among bladder cancer patients. We observed an increasing occurrence of p53 mutations in nonsmokers (5 of 17, 29%), former smokers (8 of 2 1, 38%), and current smokers (9 of 16, 56%) in that order; however, th is was not statistically significant. The most prevalent type of mutat ion was G:C to A:T transition. Tumor grade was not associated with the frequency of mutations, but the higher stage (T-3-T-4) tumors appeare d to have mutations more frequently than did the less invasive tumors (T-1-T-2).