RESUMO
OBJECTIVE: To determine the secretor expression in patients with bladder cancer, adenoma of the prostate and normal subjects. METHODS: The secretor character was determined in saliva of normal subjects (n = 40), patients with bladder cancer (n = 61) and adenoma of the prostate (n = 44) by the technique of hemoagglutination inhibition. RESULTS: 80% of the normal subjects were found to be secretors, which is in agreement with the data reported in the literature. Only 23 (37.71%) of the patients with bladder cancer were secretors and 24 (54.54%) of the patients with prostate adenoma expressed the secretor gene. CONCLUSIONS: The expression of soluble antigens decreased in patients with bladder cancer or prostate adenoma in comparison to the normal subjects. Deletion of ABH antigens in the membrane of tumor cells has been reported in other studies. This lack of expression results from a genetic alteration in the clones involved in tumor pathology. The decrease in soluble antigens in the patient groups analyzed might be due to the same mechanism of genetic alteration that could involve non tumor tissues. Most of the cancers in humans originate in epithelial cells and the changes in blood group antigens constitute an important aspect in tumor immunology.