Effects of sequential exposure to aflatoxin B1 and diethylnitrosamine on vascular and stomach tissue and additional target organs in rats.

Male weanling rats were given a standard amount (375 micrograms) of aflatoxin B1; some were then exposed to dietary diethylnitrosamine (DEN) in varying concentrations ranging from 5 to 80 ppm for 20 weeks. They were maintained for an additional period of time following DEN exposure and then killed for gross and microscopic examination. DEN at 5 ppm did not enhance aflatoxin B1 liver carcinogenesis. Ten ppm or more of DEN, however, enhanced liver carcinogenesis and introduced two additional target organs; angiosarcomas of the lung and squamous cell carcinomas of the stomach types of tumors which have not been observed after treatment with DEN alone, were noted.