Do chronic urinary tract infections induce cancer in the rat fed nitrate and aminopyrine?

Seven out of one hundred male rats in the experimental group developed malignant tumours after 18 months, during which period they were given nitrate and aminopyrine in the drinking water and had chronic urinary tract infections induced by known strains of E. coli. In the control animals, no lesions were observed in the two un-infected groups given nitrosamine precursors in the drinking water or water alone. However, two out of fifty control animals in the infected group, not administered nitrosamine precursors, developed malignant lymphoma. All rats were maintained on Purina rat chow. Our data appear to suggest that chronic urinary tract infection did induce tumour production in the rat.