The influence of urinary tract infection on the incidence of urinary tract tumors in N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide induced carcinogenesis in male Sprague-Dawley rats

Epidemiological studies have demonstrated an association between urinary tract infection and the development of bladder cancer. The present study aimed at evaluating the influence of urinary tract infection in male Sprague-Dawley rats exposed to a sub-carcinogenic dose of N-[4-(nitro-2-furyl)-thiazolyl]formamide (FANFT). A single injection of Escherichia coli into the bladder resulted in a persistent upper urinary tract infection in a high percentage of the rats. Thirty-two percent of the rats exposed to FANFT and E. coli infection developed urinary tract tumors, all but one occurring in the renal pelvis. Urinary tract tumors were not found in rats treated with FANFT or E. coli alone. The present results support that inflammation resulting from infection is actively involved in urinary tract tumorigenesis and may support the epidemiological studies showing an association between infection and human urinary tract cancer. The formation of dimethylnitrosamine or other nitroso compounds from nitrates in the urine or increased cell proliferation due to chronic inflammation or both may be important pathogenetic factors in tumor development.